The document discusses power factor and the importance of power factor improvement. It defines power factor as the ratio of active power to apparent power. Power factor is represented by the cosine of the angle between voltage and current. Reactive power causes low power factors by creating an angle between voltage and current. Lower power factors require larger equipment sizes, higher conductor sizes, and cause greater power losses. Common causes of low power factors are induction motors and lighting loads. Power factor improvement provides benefits like reduced costs, equipment sizes, and power losses. The economics of power factor improvement depends on balancing the costs of supply against correction equipment. An example calculation determines the most economical power factor for a factory.
The cosine of angle made between the voltage and current is called the power factor.
In AC circuits, there is always the phase deference between the voltage and current, which is calculated in terms of power factor.
If the load is inductive the current lags behind the voltage and the power factor is lagging.
If the load is capacitive the current leads the voltage and the power factor is leading.
The value of power factor can never be more than unity.
Basically a D.C. machine is an alternating current machine. The e.m.f. generated in the conductor is alternating in nature. With the help of the commutator segments this alternating e.m.f. is converted into a direct one.
The working of a DC generator is based on the principle that, when a conductor cuts a magnetic field, an e.m.f. is induced in the conductor.
A dynamically induced e.m.f. will be produced in the conductor when it will cut the magnetic flux as per the laws of electromagnetic induction
The cosine of angle made between the voltage and current is called the power factor.
In AC circuits, there is always the phase deference between the voltage and current, which is calculated in terms of power factor.
If the load is inductive the current lags behind the voltage and the power factor is lagging.
If the load is capacitive the current leads the voltage and the power factor is leading.
The value of power factor can never be more than unity.
Basically a D.C. machine is an alternating current machine. The e.m.f. generated in the conductor is alternating in nature. With the help of the commutator segments this alternating e.m.f. is converted into a direct one.
The working of a DC generator is based on the principle that, when a conductor cuts a magnetic field, an e.m.f. is induced in the conductor.
A dynamically induced e.m.f. will be produced in the conductor when it will cut the magnetic flux as per the laws of electromagnetic induction
Ohm's Law V = I x R (Volts = Current x Resistance). The Ohm (Ω) is a unit of electrical resistance equal to that of a conductor in which a current of one ampere is produced by a potential of one volt across its terminals. 1)Measurement of Low resistance: 1) Ammeter Voltmeter method: This is very popular method for measurement of medium resistances since ...
Winding
What is Armature winding?
Terms related to armature winding.
Single layer and double layer windings.
Comparison between closed and open windings.
Types of DC armature winding.
Types of AC armature winding.
Here we study the construction of hay's bridge, hay's bridge theory with expression, and example, hay's bridge phasor diagram. The Hay’s bridge is used for determining the self-inductance of the circuit. The bridge is the advanced form of Maxwell’s bridge.
Harmonics create pollution in our power system just like carbon dioxide and other gases create air pollution. It has adverse effects directly or indirectly on equipment like motors, transformers, induction heaters, etc. It leads to energy loss due to poor power factor.
Following content has been covered:
- The definition of harmonics is briefly interpreted.
- Factors which are responsible for harmonics current generation is discussed.
- Often the failure of equipment like motors, transformer, etc. has been put on harmonics current. But this is not always the case. This ambiguity is being tried to clear by putting content "What harmonics are not"? so that readers who are associated with operation and maintenance can efficiently do analysis and find the root cause of failure of equipment.
- IEEE Std. 519-1992, 2014 has been interpreted.
Working of synchronous machine, Construction of synchronous machine, Types o...Self-employed
Subject : AC Machine
Topic: Working of synchronous machine, Construction of
synchronous machine, Types of synchronous machine,
Application of synchronous machine
UNIT - III
FETs and Digital Circuits: FETs: JFET, V-I characteristics, MOSFET, low frequency CS and CD amplifiers, CS and CD amplifiers.
Digital Circuits: Digital (binary) operations of a system, OR gate, AND gate, NOT, EXCLUSIVE OR gate, De Morgan Laws, NAND and NOR DTL gates, modified DTL gates, HTL and TTL gates, output stages, RTL and DCTL, CMOS, Comparison of logic families.
A synchronous motor is electrically identical with an alternator or AC generator.
A given alternator ( or synchronous machine) can be used as a motor, when driven electrically.
Some characteristic features of a synchronous motor are as follows:
1. It runs either at synchronous speed or not at all i.e. while running it maintains a constant speed. The only way to change its speed is to vary the supply frequency (because NS=120f/P).
2. It is not inherently self-starting. It has to be run up to synchronous (or near synchronous) speed by some means, before it can be synchronized to the supply.
3. It is capable of being operated under a wide range of power factors, both lagging and leading. Hence, it can be used for power correction purposes, in addition to supplying torque to drive loads.
Ohm's Law V = I x R (Volts = Current x Resistance). The Ohm (Ω) is a unit of electrical resistance equal to that of a conductor in which a current of one ampere is produced by a potential of one volt across its terminals. 1)Measurement of Low resistance: 1) Ammeter Voltmeter method: This is very popular method for measurement of medium resistances since ...
Winding
What is Armature winding?
Terms related to armature winding.
Single layer and double layer windings.
Comparison between closed and open windings.
Types of DC armature winding.
Types of AC armature winding.
Here we study the construction of hay's bridge, hay's bridge theory with expression, and example, hay's bridge phasor diagram. The Hay’s bridge is used for determining the self-inductance of the circuit. The bridge is the advanced form of Maxwell’s bridge.
Harmonics create pollution in our power system just like carbon dioxide and other gases create air pollution. It has adverse effects directly or indirectly on equipment like motors, transformers, induction heaters, etc. It leads to energy loss due to poor power factor.
Following content has been covered:
- The definition of harmonics is briefly interpreted.
- Factors which are responsible for harmonics current generation is discussed.
- Often the failure of equipment like motors, transformer, etc. has been put on harmonics current. But this is not always the case. This ambiguity is being tried to clear by putting content "What harmonics are not"? so that readers who are associated with operation and maintenance can efficiently do analysis and find the root cause of failure of equipment.
- IEEE Std. 519-1992, 2014 has been interpreted.
Working of synchronous machine, Construction of synchronous machine, Types o...Self-employed
Subject : AC Machine
Topic: Working of synchronous machine, Construction of
synchronous machine, Types of synchronous machine,
Application of synchronous machine
UNIT - III
FETs and Digital Circuits: FETs: JFET, V-I characteristics, MOSFET, low frequency CS and CD amplifiers, CS and CD amplifiers.
Digital Circuits: Digital (binary) operations of a system, OR gate, AND gate, NOT, EXCLUSIVE OR gate, De Morgan Laws, NAND and NOR DTL gates, modified DTL gates, HTL and TTL gates, output stages, RTL and DCTL, CMOS, Comparison of logic families.
A synchronous motor is electrically identical with an alternator or AC generator.
A given alternator ( or synchronous machine) can be used as a motor, when driven electrically.
Some characteristic features of a synchronous motor are as follows:
1. It runs either at synchronous speed or not at all i.e. while running it maintains a constant speed. The only way to change its speed is to vary the supply frequency (because NS=120f/P).
2. It is not inherently self-starting. It has to be run up to synchronous (or near synchronous) speed by some means, before it can be synchronized to the supply.
3. It is capable of being operated under a wide range of power factors, both lagging and leading. Hence, it can be used for power correction purposes, in addition to supplying torque to drive loads.
Capacitive compensation for power–factor control
Different types of power capacitors
shunt and series capacitors
Effect of shunt capacitors (Fixed and switched)
Power factor correction
Capacitor allocation
Economic justification
Procedure to determine the best capacitor location.
Power factor correction the easiest, biggest, green initiativeRoss Welsh V.A.
Poor power factor costs our community in increased electricity charges and unnecessary
greenhouse gases. Incentives for customers to maintain the required power factor varies across
Australia fromthose that are charged a penaltyby wayofa kilovoltamperes(kVA) demand charge
to those that should comply with the local service rules, legislated or National Electricity Rules
requirements.
Micro-controller based Automatic Power Factor Correction System ReportTheory to Practical
This project report represents one of the most effective automatic power factor improvements by using static capacitors which will be controlled by a Microcontroller with very low cost although many existing systems are present which are expensive and difficult to manufacture. In this study, many small rating capacitors are connected in parallel and a reference power factor is set as standard value into the microcontroller IC. Suitable number of static capacitors is automatically connected according to the instruction of the microcontroller to improve the power factor close to unity. Some tricks such as using resistors instead of potential transformer and using one of the most low cost microcontroller IC (ATmega8) which also reduce programming complexity that make it one of the most economical system than any other controlling system.
the ratio of the actual electrical power dissipated by an AC circuit to the product of the r.m.s. values of current and voltage. The difference between the two is caused by reactance in the circuit and represents power that does no useful work.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
3. Power factor
• Definition
– The cosine of angle between voltage and current in an AC current
– It is the ratio of amount of real power to apparent power.
Lecture Notes by Dr.R.M.Larik 3
6. Power triangle diagram
• OA = VI cos φ and represents the active power in watts or kW
• AB = VI sin φ and represents the reactive power in VAR or kVAR
• OB = VI and represents the apparent power in VA or kVA
• The following points may be noted form the power triangle :
– (i) The apparent power in an a.c. circuit has two components viz.,
active and reactive power at right angles to each other.
OB2 = OA2 + AB2
or (apparent power)2 = (active power)2 + (reactive power)2
or (kVA)2 = (kW)2 + (kVAR)2
– (ii) Power factor, cos φ = OA/OB= active power /apparent power=kW/kVA
Thus the power factor of a circuit may also be defined as the ratio of active
power to the apparent power. This is a perfectly general definition and can be
applied to all cases, whateverbe the waveform.
– (iii) The lagging* reactive power is responsible for the low power factor. It is
clear from the power triangle that smaller the reactive power component, the
higher is the power factor of the circuit.
kVAR = kVA sin φ = kW/cos φ sin φ
∴ kVAR = kW tan φ Lecture Notes by Dr.R.M.Larik 6
7. • iv) For leading currents, the power triangle becomes reversed.
This fact provides a key to the power factor improvement.
If a device taking leading reactive power (e.g. capacitor) is
connected in parallel with the load, then the lagging reactive
power of the load will be partly neutralised, thus improving
the power factor of the load.
• (v) The power factor of a circuit can be defined in one of the
following three ways :
– (a) Power factor = cos φ = cosine of angle between V and I
– (b) Power factor = R/Z= Resistance/Impedance
– (c) Power factor = VIcos φ/VI= Active power/Apparent
Power
– (vi) The reactive power is neither consumed in the circuit
nor it does any useful work. It merely flows back and forth
in both directions in the circuit. A wattmeter does not
measure reactive power.Lecture Notes by Dr.R.M.Larik 7
9. Illustration
• Suppose a circuit draws a current of 10 A at a voltage
of 200 V and its p.f. is 0·8 lagging. Then,
– Apparent power = VI = 200 × 10 = 2000 VA
– Active power = VI cos φ = 200 × 10 × 0·8 = 1600 W
– Reactive power = VI sin φ = 200 × 10 × 0·6 = 1200 VAR
• The circuit receives an apparent power of 2000 VA and
is able to convert only 1600 watts into active power.
The reactive power is 1200 VAR and does no useful
work. It merely flows into and out of the circuit
periodically. In fact, reactive power is a liability on the
source because the source has to supply the additional
current (i.e., I sin φ).
Lecture Notes by Dr.R.M.Larik 9
11. Disadvantage of lower power factor
• The power factor plays an importance role in a.c. circuits since
power consumed depends upon this factor.
• It is clear from above that for fixed power and voltage, the load
current is inversely proportional to the power factor. Lower the
power factor, higher is the load current and vice-versa.
Lecture Notes by Dr.R.M.Larik 11
12. Disadvantage of lower power factor
Large kVA rating of equipment.
• The electrical machinery (e.g., alternators,
transformers, switchgear) is always rated in *kVA.
• Now, kVA = kW/cos φ
• It is clear that kVA rating of the equipment is
inversely proportional to power factor. The
smaller the power factor, the larger is the kVA
rating. Therefore, at low power factor, the kVA
rating of the equipment has to be made more,
making the equipment larger and expensive.
Lecture Notes by Dr.R.M.Larik 12
13. Disadvantage of lower power factor
• Greater conductor size
• To transmit or distribute a fixed amount of
power at constant voltage, the conductor will
have to carry more current at low power
factor. This necessitates large conductor size.
Lecture Notes by Dr.R.M.Larik 13
14. Disadvantage of lower power factor
Large copper losses
• The large current at low power factor causes
more I2R losses in all the elements of the
supply system. This results in poor efficiency.
Lecture Notes by Dr.R.M.Larik 14
15. Disadvantage of lower power factor
Poor voltage regulation
The large current at low lagging power factor
causes greater voltage drops in alternators,
transformers, transmission lines and distributors.
This results in the decreased voltage available at
the supply end, thus impairing the performance
of utilisation devices. In order to keep the
receiving end voltage within permissible limits,
extra equipment (i.e., voltage regulators) is
required.
Lecture Notes by Dr.R.M.Larik 15
16. Disadvantage of lower power factor
Reduced handling capacity of system
• The lagging power factor reduces the handling
capacity of all the elements of the system. It is
because the reactive component of current
prevents the full utilisation of installed
capacity.
Lecture Notes by Dr.R.M.Larik 16
18. Causes of lower power factor
• Most of the a.c. motors are of induction type (1φ and
3φ induction motors) which have low lagging power
factor. These motors work at a power factor which is
extremely small on light load (0·2 to 0·3) and rises to
0·8 or 0·9 at full load.
• Arc lamps, electric discharge lamps and industrial
heating furnaces operate at low lagging power factor.
• The load on the power system is varying ; being high
during morning and evening and low at other times.
During low load period, supply voltage is increased
which increases the magnetisation current. This results
in the decreased power factor.
Lecture Notes by Dr.R.M.Larik 18
19. Importance of power factor
improvement
• For consumers.
A consumer has to pay electricity charges for his
maximum demand in kVA plus the units consumed. If
the consumer imporves the power factor, then there
is a reduction† in his maximum kVA demand and
consequently there will be annual saving due to
maximum demand charges. Although power factor
improvement involves extra annual expenditure on
account of p.f. correction equipment, yet
improvement of p.f. to a proper value results in the
net annual saving for the consumer.
Lecture Notes by Dr.R.M.Larik 19
21. Importance of power factor
improvement
• For generating stations
A generating station is as much concerned with power
factor improvement as the consumer. The generators
in a power station are rated in kVA but the useful
output depends upon kW output. As station output is
kW = kVA × cos φ, therefore, number of units supplied
by it depends upon the power factor. The greater the
power factor of the generating station, the higher is
the kWh it delivers to the system. This leads to the
conclusion that improved power factor increases the
earning capacity of the power station.
Lecture Notes by Dr.R.M.Larik 21
22. Advantages of power factor
improvement
• The advantages of good (or improved) power
factor are
– reduction in load current
– increase in voltage level across the load,
– reduction in energy loss in the system (generators,
transformers, transmission lines and distributors) due
to reduction in load current
– reduction in load current
– reduction in KVA loading of the generators and the
transformers which may relieve an over loaded system
or release capacity for additional growth of load and
– reduction in KVA demand charge for large consumers
Lecture Notes by Dr.R.M.Larik 22
23. Economics of Power factor
improvement
• When the power factor is improved it involves expenditure on account of the
power factor correcting equipment. Improvement of power factor will result in
reduction of maximum demand and thus affect an annual saving over the
maximum demand charge but on the other hand an expenditure is to be incurred
every year in the shape of interest and depreciation on account of the investment
made over the power factor correcting equipment. The limit of the power factor at
which the net saving (saving in annual maximum demand charges less annual
expenditure incurred on power factor correcting equipment) is maximum is known
as economical limit of power factor correcting. It will be seen that the economical
limit of power factor correction is governed by the relative costs of the supply and
power factor correcting equipment.
• Value of most economical power factor cos Ø2 (pf after improvement) can be
determined from the expression
• Cos 2 = Øø2 = √1 - (y/x)2
• Where x is the rate per kva of maximum demand per annum and y is the
expenditure per kva per annum of the pf correction equipment. It is seen that
most economical power factor cos Ø1.
Lecture Notes by Dr.R.M.Larik 23
24. Question
A factory which has a maximum demand of 175 kW at a power factor of
0·75 lagging is charged at Rs 72 per kVA per annum. If the phase
advancing equipment costs Rs 120 per kVAR, find the most economical
power factor at which the factory should operate. Interest and
depreciation total 10% of the capital investment on the phase advancing
equipment.
Solution :
– Power factor of the factory, cos φ1 = 0·75 lagging
– Max. demand charges, x = Rs 72 per kVA per annum
– Expenditure on phase advancing equipment,
y = Rs 120 × 0·1 = Rs 12* /kVAR/annum
– Most economical p.f. at which factory should operate is
= 0·986 lagging
Lecture Notes by Dr.R.M.Larik 24