What is Induction motor
Most widely used motor in the electrical field is induction motor. This motor is one of the type of AC motor. induction motor is basically running with asynchronous speed. that means speed of the motor is not constant. when ever load increased the speed of the induction motor is reduced. the induction motor speed is purely depend on the supply voltage and suppl frequency.
Generally the induction motor speed is running lesser then synchronous speed of the motor. first we should understand what is synchronous speed. when ever the supply is connected to stator winding of the induction motor then stator produced stator magnetic flux and due to alternating supply rotating magnetic flux is produced in the stator terminal.the stator flux rotate in the speed is called synchronous speed. according to electromagnetic induction principle the rotor get induced by that stator magnetic flux and rotor also produced the rotating magnetic filed. the stator produced magnetic flux current is greater then rotor produced magnetic flux that why the induction motor always running lesser then synchronous speed .
Types of induction motor:
There are two different types of induction motor available.
- single phase induction motor
- 3 phase induction motor
single phase induction motor:
These type of induction motor does not have self starting, so its required some additional winding or starter to start the motor. these type of motor widely used in industrial and domestic purposes. further single phase induction motor is classified into 4 types.
a. capacitor start induction motor
b. capacitor start and capacitor run induction motor
c. split phase induction motor
d. shaded pole induction motor
3 phase induction motor:
These types of induction motor having self string and widely used in industrial purposes. these type of motor is very simple construction and cheaper and also less maintenance. further phase induction motor is classified into 2 types.
b. squirrel cage induction motor
Working Principle of Induction Motor
we all are know generally the motors need supply to run. if you see in dc motors we are giving two supply to stator and rotor terminal to rotate the motor. but here induction motor does not required two supply. as per the name we all are know induction motor working in the induction principle. when ever we apply current to stator winding and its produced the stator flux due to current flow in the windings. according to induction principle the rotor winding get induced and produced the rotor flux.
Now there are two flux are produced. one is stator flux another is rotor flux. the stator produced flux current is more then rotor produced flux current. so induction motor always run lesser then synchronous speed. according to lense lwa the the difference in the flux get produced torque and its start to rotate the rotor in the direction of rotating magnetic flux. so the speed of induction motor is always depend on the supply volatge and frequency . its given by the formula,
N- speed of the motor
F- supply frequency
P- Number of poles