This manual consists of some important experiments of ac electrical machines.This is prepared by satish babu and lokesh.They are working as staff in usha rama college,telaprolu.
This project report describes the design and components of a 12V DC to 220V AC converter. The key components are an inverter, step-up transformer, rechargeable battery, battery charger, resistors, capacitors, transistors, LED bulb, and MOSFET. The inverter uses an oscillator and amplifier circuit with MOSFETs to generate a 50Hz square wave that is stepped up by the transformer to 220V AC. The battery provides 12V DC power input and can be recharged by the battery charger. The converter effectively powers loads up to 85W by converting stored DC battery power to a 220V AC output.
WHAT IS TRANSFORMER, DEFINE TRANSFORMER, TYPES OF TRANSFORMER, RATINGS OF TRANSFORMERS, MANUFACTURING PROCESS OF TRANSFORMER, PARTS OF TRANSFORMER, TESTS OF TRANSFORMER, COSTING OF COPPER.
This document discusses AC power, power factor, and power factor correction. It defines active power, reactive power, and apparent power. It explains that power factor is the cosine of the angle between the voltage and current waveforms, and that most loads have a lagging power factor less than 1 due to their inductive nature. This causes issues like increased conductor size and utility charges. Power factor can be corrected by using static capacitors or a synchronous condenser to supply leading reactive current to balance the load's lagging current.
This document provides a summary of key aspects of transformer basics:
- It describes the working principle of transformers using Faraday's law of electromagnetic induction and discusses the main parts of a transformer including its magnetic core and windings.
- It lists different types of transformers classified by their use, construction, cooling method and other factors. Common types include distribution, power, control, and instrument transformers.
- Key aspects of distribution transformers like primary and secondary voltages, capacities, construction types and impedance ranges are outlined.
- Star and delta connections are explained along with diagrams and equations relating line and phase voltages. Advantages and disadvantages are also summarized.
- Other transformer components like tap changers, bushings
This chapter discusses per unit representation, which expresses values like current, voltage, impedance, and power as a ratio of an actual value to a reference or base value. This makes the quantities unitless and independent of physical size or ratings. The document provides examples of converting actual values to per unit values and explains the advantages, which include representing apparatus values consistently over a wide range, simplifying computations, and specifying machine impedances in per unit values according to manufacturers.
This document summarizes a research paper on implementing smooth transitions between optimal control modes in a switched reluctance motor (SRM). It begins with introductions to SRM technology and an overview of the paper contents. It then covers the operating principles, characteristics, control strategies, and modes of operation of SRMs. The document describes the development of a Simulink model for a proposed optimal controller, including subsystems for pulse width modulation and single pulse control. Simulation results are presented and analyzed for no-load operation, with load, and under speed and torque dynamics. The analysis shows the controller varies turn-on and turn-off angles optimally under different operating conditions to reduce ripple and enable smooth transitions between control modes. The conclusion
Tap changers are devices fitted to power transformers that allow for regulation of the output voltage. Voltage regulation is achieved by altering the number of turns in one winding of the transformer, which changes the transformer ratios. Tap changers offer variable control to keep the supply voltage within limits. They can be on load or off load tap changers. On load tap changers consist of a diverter switch and selector switch to transfer current between taps without interruption.
This document contains instructions for performing experiments on electrical machines in a lab. It provides safety guidelines and procedures for two experiments: 1) Speed control of a DC shunt motor using armature and field control methods. Graphs of speed vs armature voltage and speed vs field current are to be plotted. 2) Open circuit and short circuit tests on a single-phase transformer to determine its equivalent circuit parameters and efficiency. Calculations are to be shown to find the transformer's resistance, reactance, regulation, and efficiency at different loads. Precautions for working in the machine lab and sample viva questions are also included.
This project report describes the design and components of a 12V DC to 220V AC converter. The key components are an inverter, step-up transformer, rechargeable battery, battery charger, resistors, capacitors, transistors, LED bulb, and MOSFET. The inverter uses an oscillator and amplifier circuit with MOSFETs to generate a 50Hz square wave that is stepped up by the transformer to 220V AC. The battery provides 12V DC power input and can be recharged by the battery charger. The converter effectively powers loads up to 85W by converting stored DC battery power to a 220V AC output.
WHAT IS TRANSFORMER, DEFINE TRANSFORMER, TYPES OF TRANSFORMER, RATINGS OF TRANSFORMERS, MANUFACTURING PROCESS OF TRANSFORMER, PARTS OF TRANSFORMER, TESTS OF TRANSFORMER, COSTING OF COPPER.
This document discusses AC power, power factor, and power factor correction. It defines active power, reactive power, and apparent power. It explains that power factor is the cosine of the angle between the voltage and current waveforms, and that most loads have a lagging power factor less than 1 due to their inductive nature. This causes issues like increased conductor size and utility charges. Power factor can be corrected by using static capacitors or a synchronous condenser to supply leading reactive current to balance the load's lagging current.
This document provides a summary of key aspects of transformer basics:
- It describes the working principle of transformers using Faraday's law of electromagnetic induction and discusses the main parts of a transformer including its magnetic core and windings.
- It lists different types of transformers classified by their use, construction, cooling method and other factors. Common types include distribution, power, control, and instrument transformers.
- Key aspects of distribution transformers like primary and secondary voltages, capacities, construction types and impedance ranges are outlined.
- Star and delta connections are explained along with diagrams and equations relating line and phase voltages. Advantages and disadvantages are also summarized.
- Other transformer components like tap changers, bushings
This chapter discusses per unit representation, which expresses values like current, voltage, impedance, and power as a ratio of an actual value to a reference or base value. This makes the quantities unitless and independent of physical size or ratings. The document provides examples of converting actual values to per unit values and explains the advantages, which include representing apparatus values consistently over a wide range, simplifying computations, and specifying machine impedances in per unit values according to manufacturers.
This document summarizes a research paper on implementing smooth transitions between optimal control modes in a switched reluctance motor (SRM). It begins with introductions to SRM technology and an overview of the paper contents. It then covers the operating principles, characteristics, control strategies, and modes of operation of SRMs. The document describes the development of a Simulink model for a proposed optimal controller, including subsystems for pulse width modulation and single pulse control. Simulation results are presented and analyzed for no-load operation, with load, and under speed and torque dynamics. The analysis shows the controller varies turn-on and turn-off angles optimally under different operating conditions to reduce ripple and enable smooth transitions between control modes. The conclusion
Tap changers are devices fitted to power transformers that allow for regulation of the output voltage. Voltage regulation is achieved by altering the number of turns in one winding of the transformer, which changes the transformer ratios. Tap changers offer variable control to keep the supply voltage within limits. They can be on load or off load tap changers. On load tap changers consist of a diverter switch and selector switch to transfer current between taps without interruption.
This document contains instructions for performing experiments on electrical machines in a lab. It provides safety guidelines and procedures for two experiments: 1) Speed control of a DC shunt motor using armature and field control methods. Graphs of speed vs armature voltage and speed vs field current are to be plotted. 2) Open circuit and short circuit tests on a single-phase transformer to determine its equivalent circuit parameters and efficiency. Calculations are to be shown to find the transformer's resistance, reactance, regulation, and efficiency at different loads. Precautions for working in the machine lab and sample viva questions are also included.
Working principle of synchronous generator,Synchronous motor, Working princip...Prasant Kumar
#Working principle of synchronous generator
#Working principle of synchronous motor
#Working principle of alternator
#Synchronous machine kaise work karta hai
A generator is a device that convert Mechanical energy into electrical energy using electromagnetic induction.
A DC generator produces direct power based on fundamental principle of Faraday's laws of electromagnetic induction.
According to this laws, Whenever a conductor is moved within a magnetic field in such a way that the conductor cuts across magnetic lines of flux, voltage is generated in the conductor.
Syllabus
Introduction of Machine
Classification of Machine
Construction of DC, Induction & Synchronous machine
Working Principle of
DC Machine
Induction machine
Synchronous machine
EMF Equation of all machine
………
A transformer works on alternating current, while a DC machine works on Direct Current
It has two main parts :
Stator – It is the stationary part. It does not move or rotate.
Rotor – It is the rotating part of the machine.
YOKE
It is the outermost part of a DC motor. It is made of cast iron or cast steel.
It provides mechanical protection to the inner parts of the machine.
Provide low reluctance path for the magnetic flux.
Pole core
These are made of cast steel laminations.
The main purpose is to hold the field windings .
The end portion of the pole is called pole shoe.
FIELD WINDING
They are enameled copper wires wound around the poles
When current passes through series connected windings then adjacent poles attain opposite polarity
Armature core
This is the rotating part of the machine
It is a cylindrical structure with slots around its outer periphery.
It houses conductors in the slots.
It provides easy path for magnetic flux
Introduction of Machine,Classification of Machine,Construction of DC, Induction & Synchronous machine,Working Principle,DC Machine,Induction machine,Synchronous machine,EMF Equation of all machine
A DC generator converts mechanical energy into electrical energy using electromagnetic induction. It consists of a magnetic frame, field poles, an armature, and a commutator. The armature rotates under the poles, cutting the magnetic flux and inducing an EMF. The commutator converts the alternating EMF into a pulsating DC voltage. DC generators are classified as separately excited, self-excited (series, shunt, compound), depending on how the field is connected. A DC motor operates on the principle that a current-carrying conductor in a magnetic field experiences a torque. It consists of an armature, field poles, a commutator, and brushes. The back EMF opposes the applied voltage
This document provides an overview of power electronics topics including semiconductor devices, controlled rectifiers, DC choppers, inverters, and AC choppers. It discusses various semiconductor devices used in power electronics like power diodes, transistors, BJTs, MOSFETs, IGBTs, SITs, thyristors, SCRs, TRIACs, and GTOs. It covers the structures, characteristics, and applications of these devices. It also compares different semiconductor devices and discusses switching and safe operating areas.
The document discusses synchronous generators and their operation. It covers:
- The two reaction theory which separates the armature mmf into direct and quadrature axis components.
- How phasor diagrams can be used to represent the direct and quadrature axis reactances (Xd and Xq).
- The slip test method to measure Xd and Xq by taking voltage-to-current ratios with the armature mmf aligned to each axis.
- Important cautions for the slip test including keeping slip extremely low to avoid errors from damper windings or open circuit voltages reaching dangerous levels.
This document discusses different types of DC generators, including separately excited, self-excited, series, shunt, and compound generators. It provides details on how each type works, including the positioning of field coils and how current flows. Compound generators are described as having both series and shunt field windings to overcome disadvantages of series and shunt generators. Short shunt and long shunt compound generators are also explained in terms of how armature and field currents are calculated.
1) Synchronous machines have a rotor supplied by an external DC source that produces a rotating magnetic field. This induces a voltage in the stator windings.
2) The rotor can have either salient or non-salient poles and is laminated to reduce eddy currents. DC power is supplied to the rotor via slip rings and brushes or a brushless exciter.
3) An equivalent circuit model represents the internal generated voltage and accounts for armature reaction, inductance, and resistance effects on the terminal voltage.
Design factors; Limitations; Modern trends; Electrical
Engineering Materials; Space factor; Choice of Specific
Electric and Magnetic loadings; Thermal Considerations;
Heat flow; Temperature rise; Insulating Materials; Properties;
Rating of Machines; Various Standard Specifications ;
- A DC motor converts electrical energy into mechanical energy through electromagnetic principles. It has a rotor that rotates when current passes through the motor's armature winding within a magnetic field.
- The key components of a DC motor are the armature winding, field winding, commutator, and brushes. The field winding generates a magnetic field and the armature winding cuts this field to produce torque when powered.
- DC motors can be shunt wound, series wound, or compound wound depending on how the field winding is connected in relation to the armature winding. This determines the speed and torque characteristics of the motor.
The document summarizes instrument transformers, which are used to isolate protection, control, and measurement equipment from high voltages in power systems. It discusses current transformers (CTs) and potential transformers (PTs). CTs reduce system current to a lower value for measurement. They function by inducing a current in a secondary winding from the magnetic field of a primary winding connected to the power circuit. PTs provide isolation from high voltages and measure voltage. They have errors in voltage ratio and phase angle between primary and secondary voltages.
This document introduces a simple low power inverter circuit that uses an IC CD4047 to generate a square wave that switches transistors connected to a transformer. The transformer converts the DC input to a 230V AC output. The circuit uses common components like capacitors, resistors, transistors, diodes and a transformer. It has advantages of providing clean output and requiring little maintenance while its disadvantages include limited capacity and inability to drive inductive loads. Potential applications include powering devices from DC sources and serving as portable AC power sources.
The document discusses DC motors. It begins with an introduction to DC motors, noting they convert electrical to mechanical energy. It then covers the principles, construction, types, and applications of DC motors. The principles section explains how DC motors work using electromagnetism and the Lorentz force. Construction includes field and armature windings. There are three main types - shunt, series, and compound motors - which vary in how their field windings are connected. Applications include uses for different motor types like fans, tools, and mills.
This document provides an overview of two reaction theory, phasor diagrams, and slip tests for analyzing salient-pole generators. It explains that two reaction theory separates the armature mmf and flux into direct and quadrature axis components. A phasor diagram is also presented. Slip tests are described as a way to measure the direct axis and quadrature axis reactances (Xd and Xq) by taking voltage-to-current ratios at different points in the slip cycle when the armature mmf is aligned with either axis. Cautions for low slip are also noted when conducting these tests. References on electric machinery are listed at the end.
This document discusses various speed control methods for DC motors. It summarizes that the speed of a DC motor is directly proportional to the back EMF and inversely proportional to flux. For shunt motors, speed can be controlled through flux control by adding resistance to the field winding, armature control by adding resistance in series to the armature, and voltage control by varying the supply voltage. For series motors, speed is controlled through flux control methods like field and armature diversion, tapped fields, and paralleled fields as well as adding resistance in series with the armature. Series-parallel control is also described for variable speed applications.
The document discusses DC machines and motors. It provides explanations of Maxwell's corkscrew rule and Fleming's left-hand and right-hand rules for determining the direction of magnetic fields. It also describes the construction and working principles of DC generators and motors, including their components like the armature, commutator, and field windings. Various types of DC machines are classified based on their excitation and winding configurations. The document also covers topics like armature reaction, speed control methods, and applications of different DC motor types.
Armature reaction is the effect of current flowing in the armature windings on the main field flux in a DC machine. It causes two undesirable effects: 1) a reduction in the main field flux per pole, and 2) distortion of the main field flux wave along the air gap. Armature current produces cross-flux that either aids or weakens the main flux depending on its location. This results in a non-uniform flux distribution and a shift in the magnetic neutral axis in the direction of rotation for a generator and against rotation for a motor. It also causes demagnetization due to magnetic saturation, further reducing the main field flux from its no-load value.
IDEAL AND PRACTICAL TRANSFORMER, EQUIVALENT CIRCUIT OF TRANSFORMER|DAY5|BASIC...Prasant Kumar
#IDEAL_PRACTICAL_TRANSFORMER
#EQUIVALENT_CIRCUIT OF TRANSFORMER
#BASIC ELECTRICAL ENGINEERING
#IDEAL TRANSFORMER ON NO LOAD
#PRACTICAL TRANSFORMER ON LOAD
#ELECTRCL TRANSFORMER
#SINGLE PHASE TRANSFORMER
Link of all sessions are.
DAY 1 (Need/Definition)
https://youtu.be/BvaykFJ_NoE
DAY 2 (Working principle and Construction)
https://youtu.be/06rgxocihaM
DAY 3 (EMF equation and Turns Ratio)
https://youtu.be/g7e5xBPmv3Y
DAY 4 (Classification of Transformer)
https://youtu.be/6NP5L4MlvY4
DAY 5 ( Ideal and practical transformer on no load)
(Equivalent Transformer)
https://youtu.be/6LCLQC1p3lg
DC motors convert electrical energy into mechanical energy. There are two main types - AC and DC. A DC motor has a stationary magnetic field and an armature that rotates. The interaction between the magnetic field and current in the armature causes it to rotate. DC motors are classified as shunt, series, or compound based on how the field and armature circuits are connected. Shunt motors are constant speed, series motors have high starting torque but variable speed, and compound motors have characteristics of both.
Transmission lines require protective schemes due to their long lengths and exposure to the open atmosphere, making faults more common. The key methods for protecting transmission lines are:
1. Unit and non-unit type protections, with the main types being differential, overcurrent, distance, and carrier current protections.
2. Distance relays operate based on the impedance seen from the relay location, tripping if the impedance indicates a fault within the reach of the relay. Directional distance relays can discriminate between faults in different directions.
3. A three-step distance protection scheme uses underreach, definite reach, and overreach zones to isolate faults along the transmission line while coordinating protection across multiple line sections
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms for those who already suffer from conditions like anxiety and depression.
The document provides instructions for an experiment to determine the regulation of a 3-phase alternator using the EMF and MMF methods, which involves conducting open circuit and short circuit tests to obtain voltage and current readings at different field currents and using the data to plot graphs and calculate regulation through vector diagrams. Safety rules, equipment list, procedures, formulas, and expected results are outlined to help students successfully complete the experiment.
Working principle of synchronous generator,Synchronous motor, Working princip...Prasant Kumar
#Working principle of synchronous generator
#Working principle of synchronous motor
#Working principle of alternator
#Synchronous machine kaise work karta hai
A generator is a device that convert Mechanical energy into electrical energy using electromagnetic induction.
A DC generator produces direct power based on fundamental principle of Faraday's laws of electromagnetic induction.
According to this laws, Whenever a conductor is moved within a magnetic field in such a way that the conductor cuts across magnetic lines of flux, voltage is generated in the conductor.
Syllabus
Introduction of Machine
Classification of Machine
Construction of DC, Induction & Synchronous machine
Working Principle of
DC Machine
Induction machine
Synchronous machine
EMF Equation of all machine
………
A transformer works on alternating current, while a DC machine works on Direct Current
It has two main parts :
Stator – It is the stationary part. It does not move or rotate.
Rotor – It is the rotating part of the machine.
YOKE
It is the outermost part of a DC motor. It is made of cast iron or cast steel.
It provides mechanical protection to the inner parts of the machine.
Provide low reluctance path for the magnetic flux.
Pole core
These are made of cast steel laminations.
The main purpose is to hold the field windings .
The end portion of the pole is called pole shoe.
FIELD WINDING
They are enameled copper wires wound around the poles
When current passes through series connected windings then adjacent poles attain opposite polarity
Armature core
This is the rotating part of the machine
It is a cylindrical structure with slots around its outer periphery.
It houses conductors in the slots.
It provides easy path for magnetic flux
Introduction of Machine,Classification of Machine,Construction of DC, Induction & Synchronous machine,Working Principle,DC Machine,Induction machine,Synchronous machine,EMF Equation of all machine
A DC generator converts mechanical energy into electrical energy using electromagnetic induction. It consists of a magnetic frame, field poles, an armature, and a commutator. The armature rotates under the poles, cutting the magnetic flux and inducing an EMF. The commutator converts the alternating EMF into a pulsating DC voltage. DC generators are classified as separately excited, self-excited (series, shunt, compound), depending on how the field is connected. A DC motor operates on the principle that a current-carrying conductor in a magnetic field experiences a torque. It consists of an armature, field poles, a commutator, and brushes. The back EMF opposes the applied voltage
This document provides an overview of power electronics topics including semiconductor devices, controlled rectifiers, DC choppers, inverters, and AC choppers. It discusses various semiconductor devices used in power electronics like power diodes, transistors, BJTs, MOSFETs, IGBTs, SITs, thyristors, SCRs, TRIACs, and GTOs. It covers the structures, characteristics, and applications of these devices. It also compares different semiconductor devices and discusses switching and safe operating areas.
The document discusses synchronous generators and their operation. It covers:
- The two reaction theory which separates the armature mmf into direct and quadrature axis components.
- How phasor diagrams can be used to represent the direct and quadrature axis reactances (Xd and Xq).
- The slip test method to measure Xd and Xq by taking voltage-to-current ratios with the armature mmf aligned to each axis.
- Important cautions for the slip test including keeping slip extremely low to avoid errors from damper windings or open circuit voltages reaching dangerous levels.
This document discusses different types of DC generators, including separately excited, self-excited, series, shunt, and compound generators. It provides details on how each type works, including the positioning of field coils and how current flows. Compound generators are described as having both series and shunt field windings to overcome disadvantages of series and shunt generators. Short shunt and long shunt compound generators are also explained in terms of how armature and field currents are calculated.
1) Synchronous machines have a rotor supplied by an external DC source that produces a rotating magnetic field. This induces a voltage in the stator windings.
2) The rotor can have either salient or non-salient poles and is laminated to reduce eddy currents. DC power is supplied to the rotor via slip rings and brushes or a brushless exciter.
3) An equivalent circuit model represents the internal generated voltage and accounts for armature reaction, inductance, and resistance effects on the terminal voltage.
Design factors; Limitations; Modern trends; Electrical
Engineering Materials; Space factor; Choice of Specific
Electric and Magnetic loadings; Thermal Considerations;
Heat flow; Temperature rise; Insulating Materials; Properties;
Rating of Machines; Various Standard Specifications ;
- A DC motor converts electrical energy into mechanical energy through electromagnetic principles. It has a rotor that rotates when current passes through the motor's armature winding within a magnetic field.
- The key components of a DC motor are the armature winding, field winding, commutator, and brushes. The field winding generates a magnetic field and the armature winding cuts this field to produce torque when powered.
- DC motors can be shunt wound, series wound, or compound wound depending on how the field winding is connected in relation to the armature winding. This determines the speed and torque characteristics of the motor.
The document summarizes instrument transformers, which are used to isolate protection, control, and measurement equipment from high voltages in power systems. It discusses current transformers (CTs) and potential transformers (PTs). CTs reduce system current to a lower value for measurement. They function by inducing a current in a secondary winding from the magnetic field of a primary winding connected to the power circuit. PTs provide isolation from high voltages and measure voltage. They have errors in voltage ratio and phase angle between primary and secondary voltages.
This document introduces a simple low power inverter circuit that uses an IC CD4047 to generate a square wave that switches transistors connected to a transformer. The transformer converts the DC input to a 230V AC output. The circuit uses common components like capacitors, resistors, transistors, diodes and a transformer. It has advantages of providing clean output and requiring little maintenance while its disadvantages include limited capacity and inability to drive inductive loads. Potential applications include powering devices from DC sources and serving as portable AC power sources.
The document discusses DC motors. It begins with an introduction to DC motors, noting they convert electrical to mechanical energy. It then covers the principles, construction, types, and applications of DC motors. The principles section explains how DC motors work using electromagnetism and the Lorentz force. Construction includes field and armature windings. There are three main types - shunt, series, and compound motors - which vary in how their field windings are connected. Applications include uses for different motor types like fans, tools, and mills.
This document provides an overview of two reaction theory, phasor diagrams, and slip tests for analyzing salient-pole generators. It explains that two reaction theory separates the armature mmf and flux into direct and quadrature axis components. A phasor diagram is also presented. Slip tests are described as a way to measure the direct axis and quadrature axis reactances (Xd and Xq) by taking voltage-to-current ratios at different points in the slip cycle when the armature mmf is aligned with either axis. Cautions for low slip are also noted when conducting these tests. References on electric machinery are listed at the end.
This document discusses various speed control methods for DC motors. It summarizes that the speed of a DC motor is directly proportional to the back EMF and inversely proportional to flux. For shunt motors, speed can be controlled through flux control by adding resistance to the field winding, armature control by adding resistance in series to the armature, and voltage control by varying the supply voltage. For series motors, speed is controlled through flux control methods like field and armature diversion, tapped fields, and paralleled fields as well as adding resistance in series with the armature. Series-parallel control is also described for variable speed applications.
The document discusses DC machines and motors. It provides explanations of Maxwell's corkscrew rule and Fleming's left-hand and right-hand rules for determining the direction of magnetic fields. It also describes the construction and working principles of DC generators and motors, including their components like the armature, commutator, and field windings. Various types of DC machines are classified based on their excitation and winding configurations. The document also covers topics like armature reaction, speed control methods, and applications of different DC motor types.
Armature reaction is the effect of current flowing in the armature windings on the main field flux in a DC machine. It causes two undesirable effects: 1) a reduction in the main field flux per pole, and 2) distortion of the main field flux wave along the air gap. Armature current produces cross-flux that either aids or weakens the main flux depending on its location. This results in a non-uniform flux distribution and a shift in the magnetic neutral axis in the direction of rotation for a generator and against rotation for a motor. It also causes demagnetization due to magnetic saturation, further reducing the main field flux from its no-load value.
IDEAL AND PRACTICAL TRANSFORMER, EQUIVALENT CIRCUIT OF TRANSFORMER|DAY5|BASIC...Prasant Kumar
#IDEAL_PRACTICAL_TRANSFORMER
#EQUIVALENT_CIRCUIT OF TRANSFORMER
#BASIC ELECTRICAL ENGINEERING
#IDEAL TRANSFORMER ON NO LOAD
#PRACTICAL TRANSFORMER ON LOAD
#ELECTRCL TRANSFORMER
#SINGLE PHASE TRANSFORMER
Link of all sessions are.
DAY 1 (Need/Definition)
https://youtu.be/BvaykFJ_NoE
DAY 2 (Working principle and Construction)
https://youtu.be/06rgxocihaM
DAY 3 (EMF equation and Turns Ratio)
https://youtu.be/g7e5xBPmv3Y
DAY 4 (Classification of Transformer)
https://youtu.be/6NP5L4MlvY4
DAY 5 ( Ideal and practical transformer on no load)
(Equivalent Transformer)
https://youtu.be/6LCLQC1p3lg
DC motors convert electrical energy into mechanical energy. There are two main types - AC and DC. A DC motor has a stationary magnetic field and an armature that rotates. The interaction between the magnetic field and current in the armature causes it to rotate. DC motors are classified as shunt, series, or compound based on how the field and armature circuits are connected. Shunt motors are constant speed, series motors have high starting torque but variable speed, and compound motors have characteristics of both.
Transmission lines require protective schemes due to their long lengths and exposure to the open atmosphere, making faults more common. The key methods for protecting transmission lines are:
1. Unit and non-unit type protections, with the main types being differential, overcurrent, distance, and carrier current protections.
2. Distance relays operate based on the impedance seen from the relay location, tripping if the impedance indicates a fault within the reach of the relay. Directional distance relays can discriminate between faults in different directions.
3. A three-step distance protection scheme uses underreach, definite reach, and overreach zones to isolate faults along the transmission line while coordinating protection across multiple line sections
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms for those who already suffer from conditions like anxiety and depression.
The document provides instructions for an experiment to determine the regulation of a 3-phase alternator using the EMF and MMF methods, which involves conducting open circuit and short circuit tests to obtain voltage and current readings at different field currents and using the data to plot graphs and calculate regulation through vector diagrams. Safety rules, equipment list, procedures, formulas, and expected results are outlined to help students successfully complete the experiment.
This document describes experiments on measuring power in electrical circuits. The first experiment measures three-phase power using a two-wattmeter method. Connections are made to measure power under both balanced and unbalanced load conditions. The second experiment measures single-phase power using three-ammeter and three-voltmeter methods. Power is calculated from current and voltage measurements at different power factors. The third experiment tests a single-phase energy meter under power factors of 0.5, 0.866 and 1. The final experiment investigates the voltage-current relationship and locus diagram of a series R-L circuit by varying resistance at a fixed inductance.
This document is a lab manual for an Electrical and Electronics Engineering course. It provides instructions and details for 12 experiments related to house wiring, ceiling fans, motors, and lighting equipment. The first experiment discusses assembling basic house wiring including components like switches, sockets, and an energy meter. The second experiment focuses on connecting a ceiling fan and varying its speed using a regulator. Circuit diagrams, component details, procedures, and expected results are outlined for safe and effective completion of the experiments.
This document contains the syllabus and procedures for experiments in the Electrical Machines I Lab. The experiments focus on obtaining characteristics of DC machines like generators and motors, as well as load tests to determine efficiency. Key experiments include open/load characteristics of DC generators and motors, Swinburne's test on DC shunt motors, and load tests to find efficiency of DC shunt and compound motors. Procedures provide connections, precautions and step-by-step methods for collecting data and analyzing results for each experiment.
This document outlines 10 experiments related to electrical machines and transformers. It provides the objectives and required apparatus for each experiment, which include testing transformers, DC motors and generators, AC induction motors and alternators. The experiments involve open circuit and short circuit tests, load testing, speed control, synchronization and determination of motor/generator characteristics. A variety of testing equipment such as meters, rheostats and circuit breakers are listed as required for each experiment.
Engineering practice lab manual for electronicsPadhu Ar
This document appears to be a lab manual for an electronics engineering course. It contains instructions and procedures for 5 experiments related to basic electronic components and measurements. The experiments include studying resistor color coding, measuring AC signal parameters using an oscilloscope, studying logic gates, generating a clock signal, soldering practice, and measuring ripple factor. The document provides background theory for components like resistors, capacitors, inductors, diodes, transistors, and logic gates. It also describes the use of oscilloscopes and multimeters. Tables list the experiments and apparatus required.
The manual is very useful for UG EEE students for the subject Power Electronics
By
M.MURUGANANDAM. M.E.,(Ph.D).,MIEEE.,MISTE,
Assistant Professor & Head / EIE,
Muthayammal Engineering College,
Rasipuram,
Namakkal-637 408.
Cell No: 9965768327
This document is the lab manual for the Electrical Circuit lab course at Stani Memorial College of Engineering And Technology. It provides information about the course syllabus, experiments to be performed, circuit diagrams, component values, procedures, observations, calculations, and results. The experiments cover topics like drawing circuit symbols, verifying theorems for AC and DC circuits, analyzing resistor networks, transient analysis of RC and RL circuits, and producing voltage and current graphs versus time. Safety precautions are also outlined for working with electrical components and circuits.
- The document is an electrical and electronics laboratory manual containing instructions for various experiments.
- It includes two parts - Part A contains experiments related to basic circuit theorems like superposition, reciprocity, Thevenin's, Norton's theorems. Part B includes experiments on basic electronic components like PN junction, diode characteristics.
- The given experiment is about verifying Thevenin's and Norton's theorems for a given circuit. It describes the circuit diagram, theoretical background, procedure to determine equivalent Thevenin's voltage and resistance or Norton's current and resistance.
This document discusses Sumpner's test, which is used to determine the regulation and efficiency of large power transformers. Sumpner's test involves connecting two identical transformers back-to-back, with their primaries in parallel and secondaries in series opposition. This allows them to be tested at full load conditions without actual loading. The test provides accurate measurements of total losses, including both iron and copper losses occurring simultaneously as in actual use. Its advantages are that it requires little power and tests transformers under full load conditions. The limitation is that it requires two identical transformers.
Here are the key steps to design a Hartley oscillator:
1. Choose the operating frequency fo. This will help determine component values.
2. Select the transistor. Consider gain, frequency response, power handling etc.
3. Calculate the inductance L required using the formula:
L = 1 / [4π2fo2C]
Where C is the total capacitance in the tank circuit.
4. Choose standard inductance value slightly higher than L.
5. Calculate the capacitance C required for resonance at fo using:
1 / [2π(LC)1/2] = fo
6. Choose standard capacitance values to obtain C.
7. Calculate
This document discusses short circuits, open circuits, and transformer tests. It explains that a short circuit allows current along an unintended path with little resistance, while an open circuit lacks a complete path for current flow. Transformer tests include open circuit and short circuit tests. The open circuit test determines core losses and shunt branch parameters, while the short circuit test determines copper losses and approximate circuit parameters. Instruments are connected and measurements recorded to evaluate losses and parameters from the tests.
Power System Modelling And Simulation LabSachin Airan
This document is a lab manual for a Power System Modeling and Simulation course. It provides instructions on how to simulate synchronous machines using MATLAB software. The first experiment introduces the swing equation, which models the dynamics of a synchronous generator's rotor motion. The second experiment describes how to model a synchronous machine in Simulink, including defining its electrical and mechanical parameters. The manual lists the synchronous machine model's equations and parameters that must be specified in the Simulink model block.
This document discusses the different types of losses that occur in a DC shunt machine. It identifies the main types of losses as copper or electrical losses, core or iron losses, brush losses, mechanical losses, and stray load losses. It provides details on each type of loss, such as that copper losses occur in the machine windings due to resistance and that core losses are about 20% of full load losses and include hysteresis and eddy current losses. The document aims to explain the concept of losses in a DC shunt machine.
This document provides instructions for performing tests to generate the V curve and inverted V curve of a three phase synchronous motor. The V curve shows the relationship between armature current and field current under constant mechanical load. The inverted V curve shows the relationship between power factor and field current. Tests are conducted by varying the field current of the synchronous motor and measuring the corresponding armature current and power factor. Readings are recorded in a table and curves are plotted to analyze the motor's performance under different excitation levels and loads. Safety precautions are outlined and the components needed, including meters, rheostats and switches, are listed.
The document is an electrical machines laboratory manual that provides instructions and procedures for various experiments involving DC machines. It includes circuit diagrams and procedures for open circuit and load tests on DC shunt generators and motors to obtain their characteristics curves. Procedures are also given for load tests on DC series motors and Swinburne's test to determine the efficiency of a DC machine working as both a motor and generator. The document lists the required equipment and provides formulas used in calculations along with sample tabulations and graphs.
This document describes an experiment conducted on a three-phase induction motor using a squirrel cage rotor. The objectives are to demonstrate the operating characteristics of the motor and record its load characteristics under star and delta connections. The procedures involve connecting the motor in star and delta configurations and measuring voltage, current, speed, power factor, efficiency and slip at various torque loads. The results are recorded in tables and graphs are plotted showing the relationships between the various parameters. The aim is to examine the motor's performance characteristics under different connections and loads.
The document is a lab manual for experiments with analog electronics and cathode ray oscilloscopes (CROs). It includes:
1) An introduction to CRO components and how they work to display voltage signals over time.
2) Instructions for two experiments - the first to familiarize students with CRO functions like measuring voltage, current, frequency and phase shift. The second examines the performance of half wave, full wave and bridge rectifiers with and without capacitor filters.
3) Details on CRO measurements including amplitude, frequency, and the design of rectifier circuits.
POWER SYSTEM SIMULATION LAB-1 MANUAL (ELECTRICAL - POWER SYSTEM ENGINEERING )Mathankumar S
This document discusses the computation of parameters for single and double circuit transmission lines. It provides the theoretical background on line parameters such as resistance, inductance, capacitance. Formulas are given for calculating inductance and capacitance based on the geometric mean distance and radius for different conductor arrangements including single circuit, three phase symmetrical, asymmetrical transposed lines and double circuit transposed lines. Sample exercises are given to calculate the inductance and capacitance of given transmission line configurations and verify the results using software.
This experiment involves drawing the V and inverted V curves of a 3-phase synchronous motor under no-load and load conditions. The V curve shows the relationship between field current (I) and terminal voltage (V) of the motor. The inverted V curve shows the relationship between power factor and field current. Under normal excitation, the power factor is unity. Under-excitation results in lagging power factor while over-excitation results in leading power factor. The curves are drawn to determine the operating characteristics of the synchronous motor at different excitation levels.
This document provides instructions for an experiment to measure the efficiency and regulation of a single-phase transformer. The experiment involves applying different loads to the transformer secondary from no load to full load and measuring the primary and secondary voltages and currents. Efficiency is calculated as the ratio of output power to input power. Regulation is the percentage difference between no-load and full-load secondary voltages relative to the full-load voltage. Readings are recorded in a table and graphs of efficiency and regulation versus output power are plotted. The experiment allows determining the efficiency and regulation of the transformer at different loads.
The document describes an experiment to convert three-phase power to two-phase power using a Scott connection. A Scott connection uses two single-phase transformers, with one transformer having a center-tapped primary winding called the main transformer, and the other having an 0.866 tap on the primary called the teaser transformer. The center tap of the main transformer is connected to the 0.866 tap of the teaser transformer. This configuration allows the three-phase input to be converted to a two-phase output without using the full rating of the transformers. The experiment involves connecting the three-phase input to the primary windings and measuring voltages and currents on the secondary side to demonstrate two-phase power production.
The document describes tests conducted on a single-phase transformer to determine its efficiency and regulation. An open circuit test was conducted to measure no-load losses. A short circuit test was used to determine copper losses and develop an equivalent circuit model. Efficiency was calculated at various load levels and power factors based on losses from the two tests. Regulation was also calculated using the short circuit test results. Plots of efficiency versus load and tables of efficiency and regulation values are presented.
This document contains the syllabus and procedures for experiments in the Electrical Machines I Lab. The experiments focus on obtaining characteristics of DC machines like generators and motors, as well as transformers. Key experiments include open/load characteristics of DC generators and motors, efficiency tests, and open/short circuit tests for transformers. Precautions are outlined and tabular columns provided to record readings and calculate performance parameters like efficiency.
The manual is useful for PG students belongs to ME power Electronics and Drives
By
M.MURUGANANDAM. M.E.,(Ph.D).,MIEEE.,MISTE,
Assistant Professor & Head / EIE,
Muthayammal Engineering College,
Rasipuram,
Namakkal-637 408.
Cell No: 9965768327
This document provides instructions for Laboratory 2 of an Electrical Engineering fundamentals lab manual. The lab focuses on voltage and current dividers, as well as Wheatstone bridges. Students are asked to complete pre-lab calculations and simulations to analyze voltage and current dividers, and open/short circuit conditions of a Wheatstone bridge. The objectives are to understand how voltage and current dividers work, validate formulas for output voltage and current, understand the impact of load resistors, and analyze Wheatstone bridges. Students will build divider circuits in lab and record measurements to compare to their pre-lab calculations and simulations.
The document provides instructions for experiments on power electronics laboratory equipment. It includes circuits and procedures to study the characteristics of SCR, MOSFET, IGBT using different firing circuits like R, RC and UJT. The objectives are to draw the output and transfer characteristics of these devices, determine threshold voltages and understand the operation of different firing circuits. Graphs are plotted from the observations and results are analyzed to understand the concepts of latching current, pinch-off voltage and voltage/current control of the devices.
The document describes how to conduct short circuit and open circuit tests on transformers using a DPATT-3Bi device to measure copper and iron losses, respectively. It provides details on the test setups, calculations for full load current and no load current, and how to interpret the results displayed on the DPATT-3Bi screen. The document also lists standard limits for transformer impedance voltages and losses according to Indian standards.
This document provides instructions for students taking an Electrical and Electronics Engineering laboratory course on Power Electronics and Drives. It begins with general safety instructions for all EEE lab courses, such as being punctual and wearing proper attire. Next, it lists 13 experiments to be performed in the course, covering topics like gate pulse generation, characteristics of power electronic devices, and converter circuits. Finally, it provides details on the experiments, including circuit diagrams, procedures, expected waveforms, and requirements for recording observations and results. The document aims to prepare students for experiments examining key concepts in power electronics and motor drives.
This document appears to be a lab manual for basic electronics experiments. It contains 11 experiments covering topics like semiconductor diodes, rectifiers, transistors, FETs, and voltage regulators. Each experiment section includes the aim, apparatus, circuit diagram, theory, procedure, observations/results, and conclusion. The manual is intended for use by students at Samarth College of Engineering and Technology to learn practical skills in basic electronics components and circuits.
The document provides an orientation for experiments to be conducted in the EMEC lab, including testing various electrical machines using different circuits and measurements. Experiments will involve open and short circuit tests on transformers, motors, and generators using equipment mounted on various panels that receive single or three phase AC power as well as DC power sources. Proper safety procedures and experimental methods are outlined.
This document discusses testing, efficiency, and regulation of transformers. It describes how open circuit and short circuit tests are used to determine the parameters of an equivalent circuit model for a transformer. The open circuit test provides the magnetizing reactance and core loss resistance, while the short circuit test provides the winding resistance and leakage reactance. Transformer efficiency is defined and an expression is derived showing it depends on loading level and power factor. Maximum efficiency occurs when loading equals the ratio of core to copper losses. Regulation is also introduced but not defined. All-day efficiency accounts for varying loads over time to assess overall transformer performance.
This experiment involves studying the parallel operation of two single-phase transformers. The key points are:
1) Transformers can be connected in parallel to share the load. Important conditions are same polarity, same voltage ratio, same percentage impedance, and no circulating current.
2) Readings are taken of all ammeters, wattmeters, and voltmeters for different load values.
3) The total load current and power are distributed between the two transformers when connected in parallel.
This manual is very much useful for PG students belongs to ME Power Electronics and Drives
By
M.MURUGANANDAM. M.E.,(Ph.D).,MIEEE.,MISTE,
Assistant Professor & Head / EIE,
Muthayammal Engineering College,
Rasipuram,
Namakkal-637 408.
Cell No: 9965768327
This document provides details on laboratory experiments conducted to determine the parameters of a transformer using open and short circuit tests. The objectives are to study transformer principles and use tests to determine the equivalent circuit parameters, efficiency, and regulation. The open circuit test is conducted with the secondary open to determine no-load losses and impedance. The short circuit test is done with the secondary shorted to find the series branch parameters. Test results are provided and used to calculate values for the equivalent circuit components and transformer characteristics.
This document describes experiments to be performed in an electronic devices and circuits lab. It includes 12 experiments involving diodes, transistors, rectifiers, and other electronic components. The first experiment listed is to characterize a PN junction diode by measuring its forward and reverse bias voltage-current characteristics and calculating values like cut-in voltage and resistance. The second experiment involves obtaining characteristics and determining the zener breakdown voltage of a zener diode, as well as using a zener diode as a voltage regulator. The third experiment measures the performance of a full-wave rectifier both with and without a filter capacitor, determining values like ripple factor and regulation percentage.
Analog and Digital Electronics Lab ManualChirag Shetty
This document provides details on 12 experiments conducted in an Analog and Digital Electronics Lab. The first experiment involves simulating clipping and clamping circuits using diodes. The second experiment involves simulating a relaxation oscillator using an op-amp and comparing the frequency and duty cycle to theoretical values. The third experiment involves simulating a Schmitt trigger using an op-amp and comparing the upper and lower trigger points. The remaining experiments involve simulating circuits such as a Wein bridge oscillator, power supply, CE amplifier, half/full adders, multiplexers, and counters. Procedures and calculations are provided for analyzing and verifying the output of each circuit simulation.
To understand the basic working principle of a transformer.
To obtain the equivalent circuit parameters from Open circuit and Short circuit tests, and to estimate efficiency & regulation at various loads.
How to Manage Your Lost Opportunities in Odoo 17 CRMCeline George
Odoo 17 CRM allows us to track why we lose sales opportunities with "Lost Reasons." This helps analyze our sales process and identify areas for improvement. Here's how to configure lost reasons in Odoo 17 CRM
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LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
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advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
This presentation was provided by Steph Pollock of The American Psychological Association’s Journals Program, and Damita Snow, of The American Society of Civil Engineers (ASCE), for the initial session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session One: 'Setting Expectations: a DEIA Primer,' was held June 6, 2024.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
How to Make a Field Mandatory in Odoo 17Celine George
In Odoo, making a field required can be done through both Python code and XML views. When you set the required attribute to True in Python code, it makes the field required across all views where it's used. Conversely, when you set the required attribute in XML views, it makes the field required only in the context of that particular view.
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
1. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
Prepared by
Mr. J Satish Babu
&
Mr. A. Lokesh
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 1
2. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
OC & SC TESTS ON SINGLE PHASE TRANSFORMER
Circuit Diagram:
(a) OC Test
(b) SC Test
Name Plate Details 1Φ T/F:
KVA =
LV Voltage =
HV Voltage =
Frequency =
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 2
3. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
OC& SC TESTS ON SINGLE PHASE TRANSFORMER
Exp. No. Date:
AIM:
To predetermine the efficiency, regulation at different operating conditions by
conducting open circuit and short circuit tests on a single-phase transformer
APPARATUS:
S. No. Name Range Type Quantity
1. Voltmeter
2. Voltmeter
3. Ammeter
4. Ammeter
5. Wattmeter
6. Wattmeter
7. Single-phase variac
8. Connecting wires
PROCEDURE:
Open Circuit Test:
It is usually done on the L.V. side, keeping the H.V. side open.
1) Make the connections as shown in the circuit diagram.
2) Apply the rated V0 voltage to L.V using variac
3) Note down the no load current I0 and power W0 for rated voltage V0.
Short Circuit Test:
Short circuit test, is usually done on the H.V. side keeping the L.V. side short circuited.
i. Make connections as shown in the circuit diagram.
ii. Apply rated current (ISC) by varying variac.
iii. Note the corresponding power input (WSC) and (ISC) for VSC.
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 3
4. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
OBSERVATIONS:
O.C. Test:
Current Power
Voltage I0 (amps) W0(Watts)
V0 (Volts)
S.C. Test:
Current Drawn Power Input
Voltage applied Isc (amps) Wsc (Watts)
VSC (Volts)
FORMULAE:
From O.C. Test:
w0
No Load Power factor = Cos f0 = =
f0 =
V0 I 0
Sin f 0 =
I w = I 0 Cos f 0 = R0 = V0 / I w =
Im = I 0 Sin f 0 = X 0 = V0 / I m =
From S.C. Test:
Total impedance referred to the H.V. side
V SC
Z 02 = =
I SC
Total resistance referred to the H.V. side
W SC
R 02 = = 2 2
I 2 SC X 02 = Z 02 - R 02
Therefore, total resistance and reactance referred to L.V. side (Primary side)
R 02 X 02
R 01 = 2
X 01 =
K K2
Where ‘k’ is transformation ratio
% Efficiency at any load and given p.f :
Let the load p.f. is Cos f and
X = actual load / full load
Then, output power at actual load = X * full load = (X) (KVA) (p.f.) = _______ Watts
Iron losses Wi = WOC =
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 4
5. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
Copper losses Wcu = (X2) (WSC) =
Total losses (Wt) = Wi + Wcu
% Efficiency = (output power)/(output + losses) =
% Voltage regulation at full load of given p.f. :
% Regulation at full load = (I2R02 Cos f + I2 X02 Sin f)/V2
% Regulation at any load = (xI2R02 Cos f + xI2 X02 Sin f)/V2
‘+’ for lagging power factor ‘-’ for leading power factor
CALCULATIONS:
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 5
6. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 6
7. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 7
8. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
Table - 1: Efficiency calculations:
Fraction of PF = Cosf
load (x) 1.0 0.8
1/4
1/2
3/4
1
Table - 2: % regulation:
MODEL GRAPHS:
1. Efficiency Vs. Output (For different power factors)
2. Regulation Vs. Power Factors
UPF
EFFICIENCY
% Reg
0.8 PF
0.2 0.6 1 0.6 0.2
X X X X X
Pf lead Pf lag
OUTPUT (WATTS)
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 8
9. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
EFFICIENCY CURVE
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 9
10. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
REGULATION VS PF CURVE
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 10
11. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
PRECAUTIONS:
1. Loose connections are to be avoided.
2. Circuit connections should not be made while power is ON.
3. Ensure variac position is zero before starting the experiment.
3. Readings of meters must be taken without parallax error.
4. While doing the open circuit test, ensure that the H.V. side is open.
5. While doing the short circuit test ensure that the L.V. side is short circuited.
6. High voltage & low voltage sides of T/F should be properly connected.
8. Check the corresponding meters are connected as per the circuit diagram of the
corresponding test
RESULT:
Efficiency & Regulation of transformer are determined and equivalent circuit is drawn
Signature of the Faculty
VIVA-VOCE QUESTIONS:
1. Why iron losses are negligible in short circuit test?
2. The leakage flux in a transformer depends upon?
3. Why is it preferred to determine the efficiency of transformer indirectly rather than by
loading it.
4. What will happen if DC supply is given to the transformer?
5. Why is the core of transformer laminated.
6. What is the role of power transformers in 'power systems'?
7. What are the assumptions made in drawing the equivalent circuit?
9. What is the condition for maximum efficiency of a 1-φ transformer?
10. Why copper losses are negligible in OC test.
11. Why low power factor wattmeter are used in OC test.
12. Why unity power factor wattmeter is used in SC test.
13. Why no load current and no load power factor is low.
14. Why transformer oil is used in the transformer.
15. Why half of LV & half of HV are placed on the same limb in Core type Practical
Transformer.
16. Why HV Winding is placed over the LV winding.
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 11
12. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
PARALLEL OPERATION OF TWO 1- ø TRANSFORMERS
SC TEST
Name Plate Details 1Φ T/F:
KVA =
LV Voltage =
HV Voltage =
Frequency =
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 12
13. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
PARALLEL OPERATION OF TWO
1-ø TRANSFORMERS
Exp. No. Date:
AIM:
To conduct parallel operation on given single phase transformers.
APPRATUS:
S. No. Item Type Range Quantity
1 Transformers of same voltage ratio
2 Ammeters
3 Voltmeters
4 Watt meters
5 Variac
6 Single pole Knife switch
PROCEDURE:
Polarity Test:
1. Connections are made as per the circuit diagram.
2. Apply voltage of say 100 V.
3. Measure voltage across terminals A-a
4. If VA-a is equal to V1+V2 then it is Additive polarity.
5. If VA-a is equal to V1-V2 then it is Subtractive polarity.
6. Mark the terminals (Dot convention) after the polarity test.
Parallel operation:
1. Connections are made as per the circuit diagram.
2. Switch on the power supply.
3. Slowly increase the voltage upto its rated value of transformer primaries.
4. Verify the voltage across the switch is one of the secondary of transformer, if it is zero,
then close the switch, otherwise switch off the supply and change for correct polarity and
repeat the steps 3 and 4.
5. After closing the switch, gradually increase the load in steps and note the values of all
meters at each step till full load is reached.
6. Decrease the load and switch off the mains supply.
7. Tabulate the readings as shown.
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 13
14. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
OBSERVATIONS:
S. NO. VPI VP2 IP1 IP2 IS1 IS2 VL IL
FORMULAE:
Draw the vector diagram for full load value and verify IS1+IS2 = IL.
For all values verify
Z1
I S1 = IL
Z1 + Z 2
Z2
IS2 = IL
Z1 + Z 2
VECTOR DIAGRAM
E = E1 = E2
Z
I 1Z 1= I 2 2
0
V2 I 1X 1
2
I2 X
I 1R
1
I2 I2 R
1
2
I1
IL
PRECAUTIONS:
1. Ensure the correct connections of the transformers.
2. Check the KVA ratings of the transformers.
3. Avoid loose connections are to be made.
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 14
15. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
CALCULATIONS:
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 15
16. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 16
17. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
RESULTS:
The two transformers have been operated in parallel and checked for the equal load sharing.
Signature of the Faculty
VIVA-VOCE QUESTIONS:
1. Define voltage regulation of a transformer?
2. What are the conditions for parallel operation?
3. Why do the transformer operated in parallel?
4. Why transformer is operated at constant frequency?
5. How to calculate power transform conductivley and inductively in auto transformer?
6. What is auto transformer?
7. How eddy current losses are reduced?
8. What is the importance of Buchloz relay?
9. Draw the phasor diagram of transformer at inductive load conditions?
10. Why transformer in KVA?
11. Define all-day efficiency of transformer.
12. Draw the phasor diagram of an auto transformer?
13. Explain the losses of transformer.
14. Why, we are calculate the all-day efficiency of a distribution transformer
15. Why, the efficiency of transformer is high a half load compared to full-load?
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 17
18. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
SUMPNER’S TEST
Name Plate Details 1st T/F: Name Plate Details 2nd T/F:
KVA = KVA =
LV Voltage = LV Voltage =
HV Voltage = HV Voltage =
Frequency = Frequency =
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19. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
SUMPNER’S TEST
Exp. No. Date:
AIM:
To conduct Sumpner’s test on two similar 1-f transformers and to find the efficiency and
regulation of each transformer at different load conditions.
APPARATUS:
S. No. Name Range Type Quantity
1. Voltmeter
2. Voltmeter
3. Voltmeter
4. Ammeter
5. Ammeter
6. Wattmeter
7. Wattmeter
8. Variac (230/270V),15A
9. Variac (230/270V),15A
10. DPST Switch
11. Connecting wires
PROCEDURE:
1. Give connections as per circuit diagram.
2. Apply a small voltage to the L.V. windings of the transformers. The voltmeter
connected across SPST must give zero reading. Otherwise interchange the HV
terminals of the transformer.
3. Now rated voltage is applied to the L.V. windings of the transformers.
4. Close the S.P.S.T. switch in secondary circuit and give supply to the secondary.
Slowly increase the voltage till the rated current flows through secondaries.
5. Note down the readings of all the meters.
OBSERVATIONS:
L.V. SIDE H.V. SIDE
V1 I1 W1 V2 I2 W2
(volts) (amps) (watts) (volts) (amps) (watts)
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20. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
FORMULAE:
Io = No load current of each transformer = I1 / 2
Vo = No load voltage of each transformer = V1
Wo = Iron losses of each transformer = W1/2
No load P.F. cos f0 = W1/ V1I1
Iw = Io cos fo
Im = Io sin fo
Ro = Vo / Iw Xo = Vo / Im referred to L.V side
Is.c = short circuit current of each transformer = I2
Vs.c = short circuit voltage of each transformer = V2 /2
Ws.c = Full load copper losses of each transformer = W2/2
Ws.c = Is.c2 RHV Zol = Vs.c. /Is.c.
Ro1 = Ws.c. / Is.c2 X o1 = Z201 - R 2 01
% Reg = I1 ´ Ro1 ´ cos f ± I1 ´ Xo1 ´ sinf / VH.V.
CALCULATIONS:
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24. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
At Cos f =
Load (Wcu) copper Output=
Input=
% load current losses= KVA.Cosf h=
S.No o/p+Wi+Wcu
(X) =X(IF.L) (X)2 Wsc (o/p ) output/input
(watt)
(amp) (watt) (watt)
25%
50%
75%
100%
At full load
S No. Cos f % Reg (lag p.fs) % Reg.(Lead p.fs)
1 0.0
2 0.2
3 0.4
4 0.6
5 0.8
6 1
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25. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
REGULATION CURVE
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26. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
PF CURVE
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27. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
MODEL GRAPHS:
1. Efficiency Vs. Output (for different power factors)
2. Regulation Vs. Power Factor
% Reg
UPF
EFFICIENCY
0.2 0.6 1 0.6 0.2
0.8 PF X X X X X
Pf lead Pf lag
OUTPUT (WATTS)
PRECAUTIONS:
1. There should not be loose connections in the circuit.
2. Don't aply the secondary current greater than full load current of a transfomrer.
3. Ensure that the variac should be at zero position while switching ON.
4. LV range voltmeter must be connected in secondary side after checking the phase
opposition.
RESULT
Efficiency and regulation of each transformer at different load conditions are calculated.
Signature of the Faculty
VIVA-VOCE QUESTIONS:
1. What is necessary condition required to conduct this test?
2. What is the condition for maximum efficiency?
3. What is all day efficiency?
4. What are the conditions for parallel operation of transformers?
5. Why transformer rating in KVA?
6. How to reduce the magnetic losses in a transformer?
7. What is the relationship between thickness of laminations, supply frequency and core
losses of the transformer?
8. What is the condition for maximum voltage regulation?
9. What is the condition for zero voltage regulation?
10. What is the load KVA corresponds to maximum efficiency?
11. How are the primaries connected in this test?
12. What are the factors affecting regulation of a transformer?
13. Comment upon the reading of wattmeter connected in the primary circuit of transformer?
14. The full-load copper losses of a transformer are 1200W, then the copper loss at one-
fourth load is?
15. Draw the equivalent circuit of a transformer?
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28. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
SCOTT CONNECTION OF TRANSFORMERS
SCOTT CONNECTION- VOLTAGE VERIFICATION
Name Plate Details 1st T/F: Name Plate Details 1st T/F:
KVA = KVA =
LV Voltage = LV Voltage =
HV Voltage = HV Voltage =
Frequency = Frequency =
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29. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
SCOTT CONNECTION OF TRANSFORMERS
Exp. No. Date:
AIM:
To obtain a balanced two-phase supply from 3-f system by using Scott connection.
APPARATUS:
S. No. Name Range Type Quantity
1. Voltmeter
2. Ammeter
3. Variac
4. Load
5. Connecting wires
PROCEDURE:
1. Connect as per the circuit diagram.
2. Ensure that the switches S1 and S2 are open.
3. Adjust the 3-f variac for min voltage at its output.
4. Switch on the AC supplies and apply the rated voltage across the primaries of the
transformers.
5. Record the voltages V1, V2 and V3 and verify that the output is a balanced two-phase
supply.
6. Switch on the Ac supply again. Adjust the output voltage of the variac as per the rated
voltage of the primaries of the transformer.
7. Close the switches S1 and S2 to load both the secondaries. Adjust equal loading
conditions also.
8. Switch off the load from both secondaries and adjust the variac, so that its output voltage
is minimum and then switch off the supply.
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30. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
SCOTT CONNECTION- LOADING
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31. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
OBSERVATIONS:
For balanced two-phase supply:
S. No. V1(V) V2(V) V3(V)
Under loaded conditions:
S. No. AM AT A1 A2 A3 V1(V) V2(V)
FORMULAE:
Verify that the vector sum of V1 and V2 should be equal to √2 times V1 or V2.
V =√(V12 +V22)
Where V is the resultant 2Ф (line to line) voltage.
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PRECAUTIONS:
1. Loose connections must be avoided.
2. Properly rated and required ranged meters are used
3. The tapping ratios must be properly observed.
RESULT:
Three-phase to two-phase conversion is obtained by using Scott connection.
Signature of the Faculty
VIVA-VOCE QUESTIONS:
1. How many transformers are needed for scott connection?
2. Is it possible to obtain 3-phase balanced system from two-phase system?
3. Why is it essential that 86.6% tapping must be there in teaser transformer?
4. What tapping should be available on the main transformer and why?
5. Comment about the iron losses occurring in main & teaser transformers, especially from
the consideration of their inequality?
6. What is the major field of application of a 2-phase ac system which is obtained from
scott connection?
7. What is the phasor difference between the output voltage of scott connection?
8. If the load on the two secondaries of scott connected transformers are different, what will
be the position of current in primary windings.
9. Where is the position of neutral point of 3-phase balanced ac system in this connection?
10. Explain why the load of closed delta is to be reduced by 43.3% when it is operated as
open delta?
11. What is utilisation factor of open delta connection?
12. Can a D-Y transformer be operated as open delta transformer?
13. What are the advantages of open delta connection?
14. Draw the phasar diagram of open delta connected transformer?
15. What will happen if the transformer is connected to DC supply?
16. What is difference between a distribution & power transformer?
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 33
34. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
BRAKE TEST ON THREE PHASE INDUCTION MOTOR
Circuit Diagram:
:
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35. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
BRAKE TEST ON THREE PHASE INDUCTION MOTOR
Exp. No. Date:
AIM:
To determine the performance characteristics of a 3-phase induction motor by performing a
brake test on it
APPARATUS:
S. No. Name Range Type Quantity
1. Voltmeter
2. Ammeter
3. Wattmeter
4. Wattmeter
5. Tachometer
6. Connecting wires
PROCEDURE:
1. Connections are made as per the circuit diagram.
2. Switch on the 3–phase AC mains, apply the rated voltage by using 3-φ variac
3. Take down the readings of all the meters, spring balance readings and the speed under no
load condition.
4. Increase the load on the motor gradually by tightening the belt.
5. Record the readings of all the meters, spring balance readings and the speed at every
setting of the load.
6. Observations may be continued up to the full load current rating of the motor.
7. Reduce the load gradually and finally unload it completely and decrease the voltage to
zero.
8. Switch off the supply.
9. Note down the effective diameter of the brake drum.
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36. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
OBSERVATIONS:
Efficiency = O/P / I/P
Input(W) = W1+W2
W Spring
r(S1–S2)9.81 Nm
O/P = 2pNT/60
(watts) Balance
Torque=
S. V I N
Cosf
No. (volts) (amps) (rpm)
W1 W2 S1 S2
1
2
3
4
5
6
7
8
9
FORMULAE:
Torque (T) = r(S1-S2 ) x 9.81 where r = radius of the drum
Output = 2pNT/60
Efficiency = Output / Input
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37. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
MODEL GRAPHS:
1. Speed Vs. Output
2. Power Factor Vs. Output
3. Efficiency Vs. Output
η
T I Pf N η N T T
I
Pf
OUTPUT % SLIP
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PERFORMANCE CURVES
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39. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
PRECAUTIONS:
1. There should not be loose connections in the circuit.
2. Don't run the machine beyond the full-load current.
3. Make sure that Auto Transformer is in zero position before starting.
RESULT:
Load test on 3-f induction motor is conducted and the various performance characteristic curves
are drawn.
Signature of the Faculty
VIVA-VOCE QUESTIONS:
1. What factors determine the direction of the motor?
2. How can the direction of rotation of the motor be reversed?
3. What modifications would necessary if a motor is required to operate on voltage
different from that for which it was originally designed?
4. What is cogging?
5. What are the indications of winding faults in an induction motor?
6. Why the number of poles of the stator and rotor of an electrical motor be equal?
7. Why skewing of rotor is done in a 3-f induction motor?
8. What is crawling
9. What is the condition for maximum efficiency of an induction motor
10. Name the different methods of speed control of an induction motor
11. What is difference between conduction and induction motor
12. Why the speed of an induction motor is always less than the synchronous speed
13. Explain the different power stages of an induction motor
14. Explain the effect of frequency changes on losses
15. What are the advantages of double-cage induction motor compared to the induction
motor
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING 39
40. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
NO-LOAD & BLOCKED ROTOR TEST ON THREE PHASE
INDUCTION MOTOR
NO-LOAD TEST
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41. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
NO-LOAD & BLOCKED ROTOR TEST ON THREE PHASE
INDUCTION MOTOR
Exp. No. Date:
AIM:
To conduct No-load test and Blocked Rotor Tests on a Three-phase Induction Motor and pre-
determine its performance by drawing the circle diagram.
APPARATUS:
S. No. Name Range Type Quantity
1. Voltmeter
2. Ammeter
3. Wattmeter
4. Tachometer
5. 3-phase variac
6. Starter
PROCEDURE :-
NO LOAD TEST -
(1) Connections are given as per the circuit diagram.
(2) Precautions are observed and motor is started on the no load.
(3) Autotransformer is varied to have rated voltage applied.
(4) The meter readings are then tabulated.
BLOCKED ROTOR TEST :-
(1) Connections are given as per circuit diagram.
(2) Precautions are observed and motor is started on full load or blocked rotor position.
(3) Autotransformer is varied to have rated current flowing in motor.
(4) The meter readings are then tabulated.
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43. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
TABULAR COLUMNS
NO LOAD TEST:
S.No Voltage Current Wattmeter W1 x Wattmeter W2 x
Voc Ioc readings (W1) mf1 readings (W2) mf2
Observed Actual Observed Actual
Volts Amps Watts Watts
1
Voc= open circuit voltage
Ioc = open circuit current
BLOCKED ROTOR TEST:
S.No. Voltage Current Wattmeter W1 x Wattmeter W2 x
Vsc Isc readings(W1) mf1 readings(W2) mf2
Observed Actual observed Actual
Volts Amps Watts Watts
1.
Vsc = short circuit voltage
Isc = short circuit current
CALCULATIONS:
From O.C. Test :
WOC
No Load Power factor = Cos f0 = =
3 V0 I 0 Ph.
f0 = , Sin f0 =
I w = I 0 Cos f0= , Im = I 0 Sin f0 =
Then,
R0 = V0 Ph / I w =
X 0 = V0 Ph / I m =
From Blocked Rotor Test:
WSC
Cos fSC = =
3 VSC I SC Ph.
WSC 3-f
WSC/ph = =
3
WSC / Ph. 1
RSC = = R1 + R2
2
I SC
V
Z 02 = SC =
I SC
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44. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
RSC = ZSC Cos fSC
XSC = ZSC Sin fSC = X1+X21
MODEL GRAPHS:
Circle Diagram
V
A
L
OUTPUT LINE
E
O
TORQUE LINE
D
O
G
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Circle Diagram
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49. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
PRECAUTIONS:
Blocked Rotor test:
1. Blocking of the rotor should be done properly.
2. Make sure to apply only a small voltage corresponding to rated current.
3. Keep the Auto Transformer in the initial position at the time of starting.
O.C. Test:
1. Remove the load on the rotor shaft properly.
2. Keep the 3-phase auto Transformer in the initial position only at the time of starting
RESULT:
Thus we obtained the equivalent circuit parameters of a 3-phase slip ring induction motor by
performing, no load, blocked rotor test on it.
Signature of the Faculty
VIVA-VOCE QUESTIONS:
1. Explain why the power input to stator with rotor blocked is nearly equal to copper losses
in the winding.
2. How can you calculate the h of Induction Motor from result of no load test & blocked
rotor test.
3. What is the difference between the rotor power input and the rotor power developed?
4. What are the losses that take place in an induction motor? State the factors on which
such losses depend.
5. What tests are to be performed on an induction motor to be able to draw its circle
diagram? What information one can get about the performance of the motor from circle
diagram? What assumptions and approximations are made in drawing the circle
diagram?
6. Explain why an Induction Motor draws heavy current as compared to its full load current
at starting.
7. Explain why the no load current of Induction Motor is much higher than that of an
equivalent T/F.
8. Explain why the power of an Induction Motor is very low at starting.
9. Explain why an Induction Motor can not runs at synchronous speed.
10. Show that the locus of Rotor of an Induction Motor is semi circle.
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50. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
REGULATION OF ALTERNATOR BY EMF & MMF METHODS
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51. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
REGULATION OF ALTERNATOR
BY EMF & MMF METHODS
Exp. No. Date:
AIM:
To obtain the % regulation of an alternator at full load by using
i. Snychronous Impedence method &
ii. MMF method at
a. UPF
b. 0.8 lag
c. 0.8 lead
APPARATUS:
S. No. Name Range Type Quantity
1. Voltmeter
2. Ammeter
3. Rheostats
4. Tachometer
PROCEDURE:
O.C. Test:
1. Give connections as per the circuit diagram.
2. Keep the resistance in the motor field circuit in its minimum position. Keep the
resistance in generator field circuit in its maximum resistance position.
3. Switch on the supply, bring the starter to its maximum position, cut off the resistance in
the motor armature circuit gradually and adjust the speed of the motor to the rated speed
of generator.
4. Keeping the speed as constant note down the open circuit voltage by varying the field
current of generator in steps till rated voltage is obtained.
5. Bring the resistance in generator field circuit to its maximum position, bring the field
resistance of motor to its minimum position and switch off the supply.
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53. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
S.C.Test:
1. Give connections as per the circuit diagram.
2. Start the motor with help of starter and adjust its speed to rated value.
3. Adjust the generator field rheostat such that rated current flows in shunt circuit armature.
Calculation of armature resistance.
1. Make the connections as per the circuit diagram. (Fig.3)
2. Switch ON the supply and by varying the resistance, note down the voltage and current
at different steps Hence calculate the armature resistance.
3. Plot O.C.C. and S.C.C. curves and calculate the synchronous impedance corresponding
to rated current.
4. Predict the regulation at various power factors.
OBSERVATIONS:
At Rated speed
O.C. Test S.C. Test
S. No Vo.c/ Ph volts If Amp S. No If Amp Is.c/ Ph volts
Armature Resistance
S. No Voltage (V) Current (I) Ra = V/I
FORMULAE:
i. Synchronous Impedance Method:
IFL = Full load short circuit current = ISC =
IF1 = Field current corresponding to full load short circuit current =
E1/Phase = O.C. voltage corresponding to field current IF1 =
E1 ( per phase) (O.C.)
Ohms
Zg (per phase) = I SC (S .C. full load Current)
2 2
X S = Z S - R a Ohms
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54. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
i. For lagging p.f’s
E 0 = (V Cos f + IR a ) 2 + (V Sin f + I X s ) 2
ii. For leading p.f’s
E 0 = (V Cos f + IR a ) 2 + (V Sin f + I X s ) 2
iii.For U.P.F.
E0 = (V + IRa ) 2 + ( I X s ) 2 =
E0 -V
% Reg ‘up’ = x 100
V
ii. MMF Method:
IF1 = field current corresponding to F.L., S.C. current from S.C. test =
IF2 = field current corresponding to rated no load voltage from O.C.C. =
for Cos f lagging p.f.
IF3 = Result vector sun of IF1 & IF2 =
at Cos f lagging
I F 3 = ( IF1 ) 2 + (IF2 )2 + 2(IF1 )(IF2 ) Cos (90 - f )
E0 = No load emf corresponding to field current IF3 from O.C.C. =
iii. For Cos-f lagging p.f. :
Replace ‘+f’ with ‘-f’ in the above equations and find IF3 and Corresponding E0.
% Reg ‘up’ = E 0 - V x 100 (find for lagg p.f. & leading p.f.)
V
MODEL WAVEFORM:
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59. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
PRECAUTIONS:
1. The motor field rheostat should kept minimum & armature rheostat in maximum position
before starting.
2. The alternator exciter field Rheostat is kept maximum position before starting the
experiment.
3. Keep all the switches in open and stator is at initial (OFF) position.
4. Check the field winding is properly connected.
5. The motor field rheostat should be kept in the minimum resistance position.
6. The alternator field potential divider should be in the maximum voltage position.
7. Initially all switches are in open position.
8. Keep the speed is constant of an induction motor while conducting o.c test.
RESULT:
The % Regulation of Alternator at different p.f’s is calculated by using mmf & synchronous
impedance methods and the result are compared.
Signature of the Faculty
VIVA-VOCE QUESTIONS:
1. What are the advantages and disadvantages of each method.
2. Why the O.C. characteristic is not linear.
3. At what value of field current should the synchronous impedance be calculated & why.
4. What are the precautions needed to conduct this experiment.
5. What are the various types of alternators.
6. What is synchronizing power & synchronizing torque.
5. Define the term synchronous Reactance.
6. Why the armature is stationary & field rotates in synchronous speed.
7. Define magnetizing, demagnetizing & cross magnetizing effect.
8. Explain armature reaction effect in synchronous motor.
9. Under what conditions regulation is of –ve.
10. What is zero power factor operation.
11. Is it possible to operate two alternations in parallel having different regulation? Why?
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60. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
SLIP TEST ON 3-PHASE ALTERNATOR
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61. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
SLIP TEST ON 3-PHASE ALTERNATOR
Exp. No. Date:
AIM:
To conduct a slip test on 3-Ф alternator and pre-determine the regulation through vector
diagram.
APPARATUS REQUIRED:
S.no Name of Apparatus Range Type Quantity
1 Ammeter (0-5)A MI 1
(0-1)A MC 1
2 Voltmeter (0-150)V MI 1
(0-5)V MC 1
3 Rheostat 250 Ω /1.5A 1
4 Tachometer Digital 1
5 TPST Switch 1
6 Connecting Wires As reqd.
PROCEDURE:
1. Note down the name plate details of motor and alternator.
2. Connections are made as per the circuit diagram.
3. Give the supply by closing the DPST switch.
4. Using the three point starter, start the motor to run at the synchronous speed by varying
the motor field rheostat at the same time check whether the alternator field has been
opened or not.
5. Apply 20% to 30% of the rated voltage to the armature of the alternator by adjusting the
autotransformer.
6. To obtain the slip and the maximum oscillation of pointers the speed is reduced slightly
lesser than the synchronous speed.
7. Maximum current, minimum current, maximum voltage and minimum voltage are
noted.
8. Find out the direct and quadrature axis impedances.
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PRECAUTIONS:
1. The motor field rheostat should be kept in minimum.
2. The direction of the rotation due to prime mover and the alternator on the motor should
be the same.
3. Initially all the switches are kept open.
FORMULAE USED:
1. Xd = Vmax/Imin Ω
2. Xq = Vmin/Imax Ω
TABULAR COLUMNS
(i) To find the Direct Axis and Quadrature axis impedances:
S.NO Vmax Vmin Imax Imin
1
2
ESULT:
Xd & Xd values are determined.
Signature of the Faculty
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VIVA-VOCE QUESTIONS
1. What is meant by salient pole type rotor?
2. What is the necessity of damper winding?
3. What is meant by Two Reaction theory?
4. State Two Reaction theory.
5. What is d axis and q axis?
6. What is meant by magnetizing and cross magnetizing component?
7. What is called slip test?
8. What is meant by power angle?
9. Compare salient pole and Non salient pole rotor.
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64. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
V AND INVERTED V CURVE OF THREE PHASE
SYNCHRONOUS MOTOR
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65. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
V AND INVERTED V CURVE OF THREE PHASE
SYNCHRONOUS MOTOR
Exp. No. Date:
AIM
To draw the V and inverted V curves of a 3 phase Synchronous Motor.
APPARATUS REQUIRED:
S.No Name of the apparatus Type Range Quantity
1 Ammeter MI
2. Voltmeter MI
3. Ammeter MC
4. Rheostat
5. Wattmeter UPF
PROCEDURE:
(1) Connections are made as per the circuit diagram..
(2) Close the TPST switch.
(3) By adjusting the autotransformer from the minimum position to the maximum position the
rated voltage is given to motor. The motor starts as an induction motor.
(4) In order to give the excitation to the field for making it to run as the synchronous motor,
close the DPST switch.
(5) By varying the field rheostat note down the excitation current, armature current and the
power factor for various values of excitation.
(6) The same process has to be repeated for loaded condition.
(7) Later the motor is switched off and the graph is drawn.
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PRECAUTION:
(1) The Potential barrier should be in maximum position.
(2) The motor should be started without load .
(3) Initially TPST switch is in open position.
GRAPH:
The graph is drawn for-
(1) Armature current Vs Excitation current.
(2) Power factor Vs Excitation current.
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V & Inverted V Curves
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RESULT:
The V-curves and inverted V-curves of the 3-phase synchronous motor have been drawn.
Signature of the Faculty
VIVA QUESTIONS:
1. Define V and Inverted V curves.
2. When Synchronous motor is is said to receive 100% excitation?
3. Define critical excitation.
4. What do you mean by under excitation and over excitation?
5. What is synchronous capacitor?
6. What is hunting?
7. Mention some application of synchronous motor.
8. What could be the reasons if a synchronous motor fails to start?
9. A synchronous motor starts as usual but fails to develop its full torque. What could be due to?
10. What are the various methods of starting synchronous motor?
11. What significant characteristic of a synchronous motor is revealed by its V-curves?
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70. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
EQUIVALENT CIRCUIT OF 1Ф INDUCTION MOTOR
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71. USHA RAMA COLLEGE OF ENGINEERING & TECHNOLOGY EM-II LAB MANUAL
EQUIVALENT CIRCUIT OF 1-Ф INDUCTION MOTOR
Exp. No. Date:
AIM:
To draw the equivalent circuit of a single phase induction motor by conducting the no-
load and blocked rotor test.
APPARATUS REQUIRED:
S.No Name of Apparatus Range Type Qty.
1 Voltmeter
2 Ammeter
3 Wattmeter
4 Connecting wires
PROCEDURE:
NO LOAD TEST:
1. Connections are given as per the circuit diagram.
2. Precautions are observed and the motor is started at no load.
3. Autotransformer is varied to have a rated voltage applied.
BLOCKED ROTOR TEST:
1. Connections are given as per the circuit diagram.
2. Precautions are observed and motor is started at blocked rotor position.
3. Autotransformer is varied to have rated current flowing in motor.
4. Meter readings are noted.
PRECAUTIONS:
NO LOAD TEST:
· Initially DPST Switch is kept open.
· Autotransformer is kept at minimum potential position.
· The machines must be started on no load.
BLOCKED ROTOR TEST:
· Initially the DPST Switch is kept open.
· Autotransformer is kept at minimum potential position.
· The machine must be started at full load(blocked rotor).
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Reff = 1.5 x Rdc
FORMULAE-
NO LOAD TEST-
Cos Ф = Wo/VoIo
Iw = Io cosФ
Im = Io sin Ф
Ro = Vo/Iw
Xo = Vo/Im
BLOCKED ROTOR TEST-
Zsc = Vsc/Isc Ω
Rsc = Wsc/Isc2 Ω
Xsc = √(Zsc2 – Rsc2) Ω
TABULATION
NO LOAD TEST-
S.No. Vo(volts) Io(amps) Wo(watts)
M.F Observed
BLOCKED ROTOR TEST-
S.No. Vsc(volts) Isc(amps) Wsc(watts)
M.F Observed
Actual
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CALCULATIONS:
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RESULT:
Signature of the Faculty
VIVA QUESTIONS:
1. What is the function of capacitor in a single phase induction motor?
2. Define double field revolving theory.
3. What are the classifications of single phase induction motor based on the method of starting?
4. What design features are incorporated in a split phase motor to make it starting?
5. What is the advantage of a capacitor start motor over a resistance split phase motor?
6. In which direction does a shaded pole motor runs?
7. Give the function performed by induction motor starter.
8. What do you mean by synchronous condenser?
9. What type of motor is used in computer drives and wet grinders?
10. What is the difference between the dc motors and single phase induction motor?
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