What are the changes occur in synchronous motor during load change?

What are the changes occur in synchronous motor during load change?

As the load is increased, the torque angle δ also increases until the condition arises when the rotor is pulled out of synchronism and the motor is stopped. Pull-out torque is defined as the maximum value of the torque which a synchronous motor can develop at rated voltage and frequency without losing synchronism.

What does a synchronous generator do?

Synchronous generators are the majority source of commercial electrical energy. They are commonly used to convert the mechanical power output of steam turbines, gas turbines, reciprocating engines and hydro turbines into electrical power for the grid. The load supplied by the generator determines the voltage.

How does the change in the excitation current affect the power factor of a synchronous motor?

As the excitation is increased, the power factor improves till it becomes unity at normal excitation. Under such conditions, the current drawn from the supply is minimum. If the excitation is further increased (i.e., over excitation), the motor power factor becomes leading.

What is the effect of field current?

So the field current has zero effect of speed of rotation of a shaft, as the load connected with shaft of motor is constant so active power provided by the motor will also remain constant. The terminal voltages (VT) are also constant these are maintained by the supply connected with motor.

What is the effect of field change on synchronous motor?

One of the most important characteristics of a synchronous motor is that, by changing the field excitation of the motor, its power factor can be made both lagging and leading.

What are the changes that can be made to self start the synchronous motor?

Answer: The synchronous motor itself does not have the ability to self-start. However, the addition of an additional winding known as damper winding (similar to squirrel cage motor) enables it to self-start. This damper winding is linked with the rotor, and works on the principle of induction motor.

How does a synchronous generator generate electricity?

In general, synchronous generator consists of two parts rotor and stator. The rotor part consists of field poles and stator part consists of armature conductors. The rotation of field poles in the presence of armature conductors induces an alternating voltage which results in electrical power generation.

How does a change of excitation affect its power factor?

A change in the excitation, thus, affects only the power factor of its output. This reduces the terminal voltage slightly, so let the excitation of the first alternator be increased so as to bring the terminal voltage back to its original value.