A magnetic field is created in the stator poles that induces resulting magnetic fields in the rotor which follow the frequency of the changing magnetic field in the stator. Two pole AC motors operating at 60 Hz will always run at approximately 3600 rpm, and four pole AC motors will have speeds around 1800 rpm.
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.
On what speed an induction motor can run Why?
An induction motor always runs at a speed less than synchronous speed because the rotating magnetic field which is produced in the stator will generate flux in the rotor which will make the rotor to rotate, but due to the lagging of flux current in the rotor with flux current in the stator, the rotor will never reach . …
At what speed induction motor will rotate?
More poles result in a lower motor speed: if all other factors are equal, a 4-pole motor will rotate at half the speed of a 2-pole motor. A 60 Hz power supply changes polarity 60 times per second, and a two-pole motor will spin at 3,600 rpm when connected to this source. A four-pole motor will only rotate at 1,800 rpm.
What is rated speed of induction motor?
Rated speed is the base speed minus the slip at full rated load. An induction motor slows as it is loaded. The induction motor must run at a speed below the revolving stator field flux. Forward motion is due to the current flowing in the cage winding.
Is it possible to run an induction machine as a motor at speed greater than synchronous speed?
The induction motor can’t be run above synchronous speed. Even with VFD, the actual speed of the motor is always less than the synchronous speed of the motor. In the case of slip ring induction motor, the motor can be run above its synchronous speed by feeding power to the rotor. No.
Why starters are used in induction motor?
⇒ The starter is a device which is basically used to limit the starting current by supplying reduced voltage to the motor at the time of starting.
What are the advantages of induction motor?
Induction Motor Advantages:
- Induction motors are simple and rugged in construction. …
- Induction motors are cheaper in cost due to the absence of brushes, commutators, and slip rings.
- They are maintenance free motors unlike dc motors and synchronous motors due to the absence of brushes, commutators and slip rings.
What is 120 in motor speed formula?
The equation for calculating synchronous speed is: S = 120 f/P speed = constant (120) times frequency of power source (60 Hz) divided by number of poles used in the motor (P).
How do you speed up an electric motor?
To speed up an induction motor, you could 1) reduce the load on it (may increase speed 2 or 3%. 2) increase the frequency of the supply power 3) re-wind the stator to have fewer pole pairs. Voltage affects the torque and the frequency decides the motor speed (for a given no. of poles of the motor).
How can a motor spin fast?
One easy way to make the motor run faster is to add another magnet. Hold a magnet over the top of the motor while it is running. As you move the magnet closer to the spinning coil, one of two things will happen. Either the motor will stop, or it will run faster.