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5. What is oscillation in synchronous motors? (what is Hunting in synchronous motors in hindi)

# What is oscillation in synchronous motors? (what is Hunting in synchronous motors in hindi)

Hello friends In this article we will know what is Hunting in synchronous motor? And how is the oscillations released? And what are the different methods of starting a synchronous motor? And what are the benefits of coiling in it? And you will know about many facts related to it.

## Hunting in Synchronous motor

When a synchronous motor is used to drive a variable load, there is some change in the speed of the motor with the change in load. Due to which vibrations are generated in the rotor. This is called Hunting in synchronous motor. The state of oscillation in a synchronous motor can also be due to the pulse frequency.

When a load is applied to the synchronous motor, the rotor poles of the synchronous motor lag behind the poles of the rotational field to form a coupled angle to provide sufficient spur linear force to produce a torque capable of carrying the load. now if synchronous motor When the load is suddenly removed, the rotor poles become exactly opposite the poles of the rotational field, but due to the inertia of the rotor, the rotor poles move forward, but these rotor poles are then pulled back. and thus the rotor poles continue to move and thus a centered oscillation is established at the new position corresponding to the new load.

## synchronous motor free from hunting

To stop the oscillation, a damping couple is applied to the rotor pole faces. These modifiers are short-circuited rods of heavy copper.

If there are oscillations in the rotor, due to the relative motion between the rotor and the rotating magnetic field, some currents are induced in the dampers and the kinetic energy of the oscillations is reduced by converting the heat of the dampers to the damper rotor. The oscillations cannot be completely eliminated because there must be some relative velocity between the rotor pole and the stator field pole for their operation. The damper coils mounted on the rotor pole faces are used to start the synchronous motor.

# Method of starting synchronous motor –

## Prime mover method

In this method a small induction motor, either a diesel or petrol engine rotating at synchronous speed, is driven by a synchronous motor. Before connecting the synchronous motor to the AC supply, it is synchronized with the bus bar by running it like an alternator, then the three phase alternating current is supplied to the stator of the synchronous motor and the first driver is removed from the motor. .

## Self starting method

Modern synchronous motors use damper winding and they are made automatic with the help of damper winding. The damper or cage coil is coiled at the ends of the rotor pole cord. This is coiled.