Contents
How does a synchronous generator work?
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.
What is internally generated voltage?
(produced in one phase) is called “internally generated” because it is not generally the voltage that appears at the terminals of the generator terminals of the generator. The only time that this internal voltage appears at the output is when there is no armature current flowing in the machine.
What is excitation voltage in synchronous motor?
Synchronous motor excitation refers to the DC supply given to rotor which is used to produce the required magnetic flux. When the synchronous motor is working at constant applied voltage V, the resultant air gap flux as demanded by V remains substantially constant.
What is voltage regulation in synchronous motor?
The voltage regulation of an alternator or synchronous generator is defined as the changes in terminal voltage on the application of load at a constant driving speed and field excitation.
What is the generated voltage?
Generated Voltage is the voltage developed across the terminals of the Generator without any load connected.
Why EMF method is called pessimistic method?
In EMF method, the voltage drop due to armature resistance (Ra) and the drop due to synchronous reactance(XS) is considered, both the drops are emf quantities. This method is also called pessimistic method, because the voltage regulation obtained by this method is more than the actual value.
How is the voltage of a synchronous generator regulated?
The Voltage Regulation of a Synchronous Generator is the rise in voltage at the terminals when the load is reduced from full load rated value to zero, speed and field current remaining constant. It depends upon the power factor of the load.
What is the power factor of a synchronous motor?
A synchronous motor’s excitation can be varied, enabling it to operate at lagging, leading or unity power factor. At minimum excitation current, the power factor is unity. In an industrial setting, large synchronous motors, besides performing useful work, can serve to modify a harmful power factor.
Why is a synchronous motor not self starting?
Due to the inertia of rest, a large synchronous motor with a heavy armature is not self-starting. Such motors can be equipped with internal induction windings or an external pony motor to get them up to speed. Many of these motors can be constructed using permanent magnets.
How is an induction motor different from a synchronous motor?
In contrast, an asynchronous motor is one in which the rotor turns at a speed slower than the synchronous speed. Induction motors are asynchronous motors. In an induction motor, a changing magnetic field induces currents in the rotor, so the rotor will always rotate more slowly than the synchronous speed of the magnetic field in the stator.