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Ac motors and their types
This document discusses different types of AC motors. It describes induction motors, including single-phase and three-phase induction motors. Three-phase induction motors can have either a squirrel cage or wound rotor. Synchronous motors are also discussed, which rotate at a constant synchronous speed. While synchronous motors have high efficiency, they require auxiliary equipment to allow for self-starting. The document compares different AC motor types and provides examples of their common applications.
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Ac motors and their types
- 1. AC Motors &Their Types GroupMembers: MAbdullah (p12-6322) SalmanSyed (p12-6403) YasarHayat (p12-6405)
- 2. Topic Introduction Electromechanicaldevice that converts electrical energy to mechanical energy. Mechanical energy used to e.g. Rotate pump impeller, fan, blower Drive compressors Lift materials Motors in industry: 70% of electrical load. What is an Electric Motor?
- 3. Principle of howmotors work
- 4. Structural Design Anelectric motor is all about magnets and magnetism: A motor uses magnets to create motion. A motor is consist of two magnets.
- 5. Classification of Motors ElectricMotors Alternating Current (AC) Motors Direct Current (DC) Motors Synchronous Induction Three-PhaseSingle-Phase Self ExcitedSeparately Excited Series ShuntCompound
- 6. AC Motors Alternating Current(AC) Motors Synchronous Induction Three-PhaseSingle-Phase
- 7. AC Motors Electricalcurrent reverses direction Two parts: stator and rotor Stator: stationary electrical component Rotor: rotates the motor shaft Two types • Synchronous motor • Induction motor stator rotor
- 8. Induction motors Induction motorscan be classified into two main groups: single-phase induction motors three-phase induction motors Single-phase induction motors: These only have one stator winding, operate with a single-phase power supply... Three –phase induction motors: The use three sets of stator coils the rotating magnetic field drags the rotor around with it.
- 9. Induction motors •Induction motorsare the most common motors used for various equipments in industry. Components Rotor • Squirrel cage • Wound rotor Stator
- 10. Single Induction motor •Singlephase motors are very widely used in home, offices, workshops etc. as power delivered to most of the houses and offices is single phase. In addition to this, single phase motors are reliable, cheap in cost, simple in construction and easy to repair.
- 15. 3 phase InductionMotor • Stator As its name indicate stator is a stationary part of induction motor. A three phase supply is given to the stator of induction motor. • Rotor The rotor is a rotating part of induction motor. The rotor is connected to the mechanical load through the shaft. The rotor of the three phase induction motor are further classified as • Squirrel cage rotor • Slip ring rotor or wound rotor or phase wound rotor
- 16.
- 17. • Advantages ofsquirrel cage induction rotor 1. Its construction is very simple and rugged 2. as there are no brushes and slip ring, these motors requires less maintenance. • Applications: Squirrel cage induction motor is used in lathes, drilling machine, fan, blower printing machines etc
- 18. Slip Ring InductionMotor • Slip ring or wound three phase induction motor : In this type of three phase induction motor the rotor is wound for the same number of poles as that of stator but it has less number of slots and has less turns per phase of a heavier conductor.The rotor also carries star or delta winding similar to that of stator winding. The rotor consists of numbers of slots and rotor winding are placed inside these slots.
- 19. • Advantages ofslip ring induction motor 1. It has high starting torque and low starting current. 2. Possibility of adding additional resistance to control speed • Applications: Slip ring induction motor are used where high starting torque is required i.e in hoists, cranes, elevator etc
- 20. Synchronous motor Asthe name suggests Synchronous motors are capable of running at constant speed irrespective of the load acting on them. Synchronous motors have got higher efficiency than its counterparts. Its efficiency ranges from 90 – 92%.
- 21. AC Synchronous motor Stator:It carries three phase winding and is fed from 3-phase supply. Rotor: It carries permanent magnet poles that rotate exactly with same speed as that of the stator magnetic field, hence the name synchronous motor. It is not self starting.
- 22. Synchronous Motor-Principle 22 The rotoracting as a bar magnet will turn to line up with the rotating magnet field. The rotor gets locked to the RMF and rotates unlike induction motor at synchronous speed under all load condition
- 23. Synchronous Speed Speed atwhich RMF rotates or Synchronous speed can easily be derived as follows, speed of synchronous motor can be very accurately controlled. This is the reason why they are suitable for high precision applications.
- 24. Why Synchronous motorsare not self starting ? North Pole of the Rotor will obviously get attracted by South Pole of RMF, and will start to move in the same direction. But since the rotor has got some inertia, this starting speed will be very low. So it will give repulsive force. This will make the rotor move backward. As a net effect the rotor won’t be able to start.
- 25. Making Synchronous MotorSelf Start • To make synchronous motor self start, a squirrel cage arrangement is cleverly fitted through pole tips. They are also called as damper windings. At the starting rotor field coils are not energized. So with revolving magnetic field, electricity is induced in squirrel cage bars and rotor starts rotating just like an induction motor starts.
- 26. Out of Synchronism •Synchronousmotors will produce constant speed irrespective of motor load only if the load is within the capability of motor. If external torque load is more than torque produced by the motor, it will slip out of synchronism and will come to rest. Low supply voltage and excitation voltage are other reasons of going out of synchronism
- 27. Application of Synchronous Motor •Synchronous motor having no load connected to its shaft is used for power factor improvement. it is used in power system in situations where static capacitors are expensive. • Synchronous motor finds application where operating speed is less (around 500 rpm) and high power is required. For power requirement from 35 kW to 2500KW, the size, weight and cost of the corresponding induction motor is very high. Hence these motors are preferably used. Ex- Reciprocating pump, compressor, rolling mills etc
Editor's Notes
- #3 Electric motors defined as electromechanical devices that convert electrical energy to mechanical energy. The mechanical energy can be used to perform work such as rotating a pump impeller, fan, blower, driving a compressor, lifting materials etc. Ultimately, motors are the interface between the electrical and mechanical systems of a facility. So, EM are an important part of any electrical system. They used throughout every manufacturing plant,office and home consuming about 70% of all electricity generated. That’s why electric motors are termed as “Work Horse” in an industry.
- #4 Electrical current flowing in a loop of wire produce a magnetic field acros the loop. When this loop is surrounded by the field of another magnet,the loop will turn, producing a force (called torque) that results in mechanical motion.
- #5 Parts of the Motor- 1.Armature or rotor 2.Commutator 3.Brushes 4.Axle 5.power supply of some sort for example- battery The contacts of the commutator are attached to the axle of the electromagnet, so they spin with the magnet.
- #6 There are numerous ways to design a motor, thus there are many different types of motors and each type possess different operating characteristics. Based on this characteristics the motor can be chosen for a specified application. We will try to explain the main types of motors and For this explanation, I am calling md mukhlesur Rahman and giving thanks to all. Allah hafez.
- #7 The stator is in the stationary electrical component. The rotor is the rotating electrical component, which in turn rotates the motor shaft. There are two types of AC motors: synchronous (see figure) and induction. The main difference between the synchronous motor and the induction motor is that the rotor of the synchronous motor travels at the same speed as the rotating magnetic field.
- #8 Stator:The stator is in the stationary electrical component. rotor: The stator is in the stationary electricalthat speed is more difficult to control for AC motors. component. The rotor is the rotating electrical component, which in turn rotates the motor shaft.
- #10 Their popularity is due to their simple design, they are inexpensive (half or less of the cost of a DC motor) High power to weight ratio (about twice that of a DC motor) easy to maintain can be directly connected to an AC power source