# A synchronous machine is called a doubly excited machine because

A synchronous machine is called a doubly excited machine because

## Why synchronous Motor is called Doubly Excited Machine

Synchronous machines:- A three-phase synchronous machine is a doubly excited machine because its field winding is energized from a dc source and its armature winding is connected to an ac source.

When this is done, torque can only be developed at one speed-the synchronous speed. At any other speed, the torque is zero. In fact, it is this characteristic (i.e doubly-fed) that enables the synchronous motor to develop non-zero torque at ~only one speed (i.e. synchronous speed) and hence the name synchronous motor.

when working as a motor, the synchronous machine takes active power from an ac source. During its working as a generator, a synchronous machine delivers, or export AC power.

When this is done, torque can only be developed at one speed-the synchronous speed. At any other speed, the torque is zero. In fact, it is this characteristic (i.e doubly-fed) that enables the synchronous motor to develop non-zero torque at ~only one speed (i.e. synchronous speed) and hence the name synchronous motor.

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