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The induction motor has self-starting torque whereas the synchronous motor is not self starting. It has to be run up to synchronous speed by any means before it can be synchronized to AC supply. A synchronous motor can be operated with lagging and leading power by changing its excitation.
What is difference between induction motor and synchronous motor?
Synchronous motors require an additional DC power source for energizing rotor winding. Induction motors do not require any additional power source. Synchronous motors require additional starting mechanism to initially rotate the rotor near to the synchronous speed. No starting mechanism is required in induction motors.
What is the difference between the synchronous and asynchronous induction motors?
The synchronous motor is a type of AC motor that runs at synchronous speed. The asynchronous motor is a type of AC motor that runs on speed less than the synchronous speed. There is no slip i.e. the slip of synchronous motor is equal to 0. There is slip in induction motor and it is always greater than 0.
What is the basic difference in construction between induction machines and synchronous machines?
A synchronous motor can run only at the synchronous speed. In a nutshell, the torque in an induction motor is produced due to the relative speed whereas in a synchronous motor, the torque production is due to the angle lag between the two fields.
What is the main disadvantage of synchronous motors?
Disadvantages or Demerits: Synchronous motors requires dc excitation which must be supplied from external sources. Synchronous motors are inherently not self starting motors and needs some arrangement for its starting and synchronizing. The cost per kW output is generally higher than that of induction motors.
What is the working principle of synchronous motor?
The principle of operation of a synchronous motor can be understood by considering the stator windings to be connected to a three-phase alternating-current supply. The effect of the stator current is to establish a magnetic field rotating at 120 f/p revolutions per minute for a frequency of f hertz and for p poles.
What 3 things are needed for an induction motor to work?
A 3-phase induction motor includes two essential components namely the stator & the rotor. In this motor, the stationary part is the stator whereas the rotating part is the rotor. In this motor, the load is connected to the shaft. Three-phase armature winding can be wound over the stator.
Why it is called induction motor?
This type of engine is also known as an induction motor. The asynchronous motor is based on the currents induced in the rotor from the rotating magnetic field of the stator. That’s why it’s called an induction machine.
Can induction motor run at the synchronous speed?
So, theoretically, the Induction motor can never run at synchronous speed. But due to the reduction of speed, again lag influx will be achieved, and the motor will continue to move at this speed due to flux difference between rotor and stator. In short, an induction motor cannot run at induction speed.
Is 3 phase induction motor is self starting?
Three-phase induction motor is self-starting, because winding displacement is 120 degrees for each phase and supply also has 120 phase shift for 3-phase. It results in a unidirectional rotating magnetic field is developed in air gap which causes 3-phase induction motor to self-start.
What are the applications of induction motor?
These are the most common type of AC motor and are important to industry due to their load capacity, with Single-Phase induction motors being used mainly for smaller loads, for example in household appliances whereas, Three-Phase induction motors are used more in industrial applications including compressors, pumps, May 5, 2016.
Where do we use synchronous motor?
Synchronous motors are normally used in applications in which a constant and precise speed is required. Typical applications of these low power motors are positioning machines. They are also used in robot actuators. Synchronous motors are also used in ball mills, watches, record players, and turntables.
What is advantage of synchronous motor?
The advantage of using synchronous motor is the ability to control the power factor. An over excited synchronous-motor has leading power factor and is operated in parallel to induction motors thereby improving the system power factor. Speed remains constant irrespective of the loads in synchronous motors.
Why do we use synchronous motors?
usually, synchronous motors are used for applications where precise and constant speed is required. While used in high power industrial sizes, these motors perform two important functions. One is as an efficient means of converting AC energy into mechanical energy and the other is Power factor correction.
What are the main parts of synchronous motor?
The Construction of Synchronous Motors A synchronous motor is generally made up of two parts, a stator the stationary part of the machine that carries the armature winding in which the voltage is generated, and a rotor the rotating part of the machine that produces the main field flux.
What are the main characteristics of synchronous motors?
Main Features of Synchronous Motors Synchronous motors are inherently not self starting. The speed of operation of is in synchronism with the supply frequency and hence for constant supply frequency they behave as constant speed motor irrespective of load condition.
What is the principle of a motor?
The principle of an electric motor is based on the current carrying conductor which produces magnetic field around it. A current carrying conductor is placed perpendicular to the magnetic field so that it experiences a force.
How does an induction motor start?
When the supply is connected to the stator of a three-phase induction motor, a rotating magnetic field is produced, and the rotor begins rotating and the induction motor starts. At the time of starting, the motor slip is unity, and the starting current is very large.
What is the cost of induction motor?
Questions & Answers on Induction Motors No of Phase Min Price Max Price Single Phase Rs 2200/Piece Rs 22093/Piece Three Phase Rs 2100/Piece Rs 47148/Piece.
What are the types of induction motors?
Types of Induction Motors Split Phase Induction Motor. Capacitor Start Induction Motor. Capacitor Start and Capacitor Run Induction Motor. Shaded Pole Induction Motor.
How can synchronous motor be stopped?
The methods that are employed for Braking of Synchronous Motor are: Regenerative braking while operating on a variable frequency supply. Rheostatic braking. Plugging.
Why synchronous motors are not self starting?
Above a certain size, synchronous motors are not self-starting motors. This property is due to the inertia of the rotor; it cannot instantly follow the rotation of the magnetic field of the stator. Once the rotor nears the synchronous speed, the field winding is excited, and the motor pulls into synchronization.
