Why Damper Winding is used in Synchronous Alternator and Motor?

Purpose of using Damper Winding in Synchronous Machine

The main purpose of using Damper winding in synchronous Machines is to provide starting torque and eliminate damping or hunting. The damper winding is used in Synchronous Motors to provide starting torque and the damper winding is used in the synchronous alternator to eliminate damping or hunting.

It is a very important and frequently asked question that,  Why Damper Winding is used in Synchronous Machines?. It is frequently asked in Interview. So you should have clear knowledge about it. So today we are going to discuss Why Damper Winding is used in Synchronous Alternator and Motor?

The simplest and shortest answer to this question is already given in the first paragraph, now we will discuss it in detail.

There are mainly two types of synchronous machines, one is a synchronous alternator and another is a synchronous motor.

What is Damper Winding?

Damper Windings are made using copper bars which are short-circuited at both ends. They act as short-circuit coils. Damper windings are placed in the face of the rotor poles of the synchronous machine along the pole axis.

Why Damper Winding is used in Synchronous Alternators?

The damper winding is used in the synchronous alternator to suppress or eliminate hunting. When in an alternator load is suddenly changes then the rotor hunts and it tries to go to a new equilibrium position.

In other words, when the load in an alternator suddenly changes(suppose it increases) then the rotor falls out of the synchronism. During this time rotor rotates less than synchronous speed.

If we use a damper winding(basically a short circuit coil), an EMF will be induced in the damper winding when the rotor rotates at less than synchronous speed. Therefore the damper winding will create a flux that will increase the speed of the rotor to catch the synchronous speed. So the damper winding always tries to keep the rotor speed at the synchronous speed even during sudden load changes in the alternator.

Thus we can eliminate hunting in the alternator using damper winding. Damper winding helps to the alternator for smoothly running.

Why Damper Winding is used in Synchronous Motors?

The purpose of using damper winding in the alternator and synchronous motor is not the same. The damper winding is used in the synchronous motor to provide starting torque.

We know that the synchronous motor is not self-starting. So to start the synchronous motor we follow various methods of starting. The method of starting using the damper winding is one of them.

Suppose a synchronous motor has damper winding. Initially, when the motor is off, the rotator is constant. When we give the main power supply to the stator winding of the synchronous motor, it creates a rotating magnetic field. Now the stator flux will cut the damper winding conductor and an emf will be induced in the damper winding as the induction motor principle.

So, initially, the synchronous motor will start as an induction motor and it will continue running after giving the auxiliary DC supply to the main field winding. When the rotor catches the synchronous speed there will be no relative speed between the stator and rotor and the damper winding will stop inducing emf. So it is clear that the damper winding works only starting time of the motor.

Thus we can start the synchronous motor using damper winding.

These were the reasons Why Damper Winding is used in Synchronous Machine.

Read Also:

• Why is Three Phase Induction Motor Self-Starting but Synchronous Motor not?
• Why is Alternator Armature Winding always connected in STAR?
• Why Capacitor is used in Single-phase Induction Motors?
• AC Motor VS DC Motor | Difference with Advantage and Disadvantage
• [BEST] Applications, Advantages, Types of Stepper Motor

Thank you for visiting the website. keep visiting for more updates.