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.

Can an induction motor runs at 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.

What happens when induction motor runs above synchronous speed?

If an external mechanical system drives the rotor above synchronous speed, the induction machine acts as a generator. If the rotor is rotating below synchronous speed, the induction machine is a motor. The relationship between rotor speed and synchronous speed is defined using the terms slip and slip speed.

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Why speed of induction motor is less than synchronous speed?

The induction motor always runs at speed less than its synchronous speed. … Due to the lag between the flux current in the rotor and the flux current in the stator, the rotor will never reach its rotating magnetic field speed (i.e. the synchronous speed).

Can synchronous motor rotate at any speed other than the synchronous speed?

At any speed other than synchronous speed, its rotor would experience an oscillating torque of zero average value as the rotating magnetic field repeatedly passes the slower moving rotor.

Why does the synchronous motor run at synchronous speed?

A synchronous motor runs at synchronous speed only because it is meant to run like that . It cannot run on a speed other than synchronous speed. Stator(N) links with Rotor(S). … For application which requires fixed speed you may use synchronous motor.

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).

What is normal slip of an induction motor?

Because of this speed difference, the motor rotates at a speed slightly slower than the synchronous speed. Slip is normally expressed in percentage. Slip of a power induction motor is 2 to 3% when the motor is operated under the rated load.

Which motor runs at synchronous speed?

Synchronous speed is a significant parameter for the rotating magnetic field-type AC motor. It is determined by the frequency and the number of magnetic poles. A collective name for the motors that run at the synchronous speed is the synchronous motor.

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At what speed will the induction motor run?

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 . …

How does an induction motor start?

A three-phase Induction Motor is Self Starting. 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.

What is rated speed of motor?

The rated speed is the speed at which the motor will first produce its maximum designed power output, and “maximum speed,” the fastest the motor can spin while producing that same amount of power./:m] ]The reduction ratio should be applied on the RPM while your load is attached to the motor.

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.

Why does synchronous motor is 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.

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How does synchronous motor change speed?

Changing the number of poles is not easy, so we do not use that method. However, with the invention of solid-state devices, the frequency of the current fed to the synchronous motor can be varied. We can control the speed of the synchronous motor by changing the frequency of the supply to the motor.

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