What is meant by the term synchronous cusps of a 3 induction motor?

Now, a cusp in torque-speed characteristic of an induction motor is what you call a synchronous cusp and it is a vertical cusp. Why it happens? Space harmonics due to variation in air-gap reluctance owing to presence of slots on stator and rotor are called slot harmonics.

How do you know if a motor is synchronous or asynchronous?

if the slip of the motor is zero or the rotor has the same rotational speed as the stator rotating field, the motor is called AC Synchronous motor. if an AC motor has a slip or there is a difference between the stator field speed and the rotor, the motor is called asynchronous motor.

What is synchronous speed in induction motor?

Synchronous speed is the speed of rotation of the magnetic field in a rotary machine. An induction motor always runs at a speed less than synchronous speed. The rotating magnetic field which is produced in the stator will generate flux in the rotor which will make the rotor rotate.

Are induction motors synchronous or asynchronous?

Among the classic examples of this phenomenon is that of induction motors and asynchronous motors. All induction motors are asynchronous motors. The asynchronous nature of induction-motor operation comes from the slip between the rotational speed of the stator field and somewhat slower speed of the rotor.

What is induced torque?

The developed Torque or Induced Torque Equation in a machine is defined as the Torque generated by the electric to mechanical power conversion. The torque is also known as Electromagnetic Torque.

What is synchronous motor and induction motor?

[What is a synchronous & Induction motors] The electromagnetic motor which converts electrical energy into mechanical work at constant speed is called as a ‘Synchronous Motor’. The electromagnetic motor which converts electrical energy into mechanical work at variable speed is called as a ‘Induction Motor’.

Can induction motor be synchronous?

In the applications where high starting torque and constant speed are desired then synchronous induction motors can be used. It has the advantages of both synchronous and induction motors. The synchronous motor gives constant speed whereas induction motors can be started against full load torque.

What is crawling in synchronous machine?

Sometimes, squirrel cage induction motors exhibits a tendency to run at very slow speeds (as low as one-seventh of their synchronous speed). This phenomenon is called as crawling of an induction motor. This action is due to the fact that, flux wave produced by a stator winding is not purely sine wave.

What is a cusp in torque-speed characteristic of an induction motor?

Now, a cusp in torque-speed characteristic of an induction motor is what you call a synchronous cusp and it is a vertical cusp. Why it happens? Space harmonics due to variation in air-gap reluctance owing to presence of slots on stator and rotor are called slot harmonics.

What is the difference between synchronous motor and induction motor?

The synchronous motor gives constant speed whereas induction motors can be started against full load torque. Consider a normal slip ring induction motor having three phase winding on the rotor as shown in the Fig. 1. Initially it is run as an slip ring induction motor with the help of starting resistances.

Why does the cogging occur in induction motors?

The cogging occurs in induction motors due to (a) harmonic induction torques. (b) harmonic synchronous torques. (c) vibration torques. (d) both (a) and (b). Answer: (b) harmonic synchronous torques. 3. Cogging of induction motors occurs at (a) high voltage and when the number of stator teeth and rotor teeth are equal.

What is the purpose of slot harmonics in induction motor?

As a result, such torque is produced at particular rotor speeds, much like synchronous motor torque production which also happens at particular speed. Hence, slots harmonics produce synchronous torques and introduce a vertical constant-speed torque characteristic (like a sync motor) into the torque speed characteristic of induction motor.