A generator excites it self due to a high power thyristors feeding to a rotor through slip rings. Once excited it lessons maintenance and operational requirements.
Either or both can be separately excited. To generate voltage you need a big magnet( the field). Most generators use an electro-magnet. Now the electro-magnet needs a source of power (electricity). We could use the generators own output to excite the field (magnet), this is called self excitation. The problem with self excitation is that we have to wait for the generator to turn and start generating, also to start generating (Building up) there must be some left over magnetism from the last time it was run (called residual magnetism) or not even a little voltage will be generated to start the field current flowing. To solve these problems we could use separately excited. This means we must have a separate source of power to excite the field to produce the magnetism. Sometimes a battery or gasoline driven generator is used to excite the field of a very large generator to get it generating and then we can use some of the generated output to either recharge the battery or switch over to from the battery. In any case we have adjustable control of the generator all the time. This is why most generators are designed to be separately excited. And that is why you car has a voltage regulator. It wakes up the alternator when the engine is started by separately exciting it (the field) with the battery and then regulates the output voltage of the alternator as the engine changes speed with the driver's commands from the gas pedal.
What is going to happen when you repeat this experiment on self D.C generator?
Residual magnetism in a self-excited generator refers to the small amount of magnetism that remains in the magnetic core after the generator has been de-energized. This residual magnetism is crucial for the initial excitation of the generator because it provides the necessary magnetic field to induce voltage when the generator is started. As the rotor turns, the residual magnetism induces a small voltage in the stator windings, which, when connected to the field windings, enhances the magnetic field and leads to self-excitation, allowing the generator to generate power. Without sufficient residual magnetism, the generator may fail to start or produce voltage.
there is problem in AVR and magnetic strength.
If a self-excited generator lost all its residual magnetism, can it build up an output voltage?
If there is no residual magnetism in the field poles then there would be no flux too induce the initial voltage for self exitation
it is the resistance with which the generatoe just excite.
The basic principle of generator excitation is that once the gasket of tie generator is being checked, the generator excits as if the block is not inserted. By egbebu emmanuel
Either or both can be separately excited. To generate voltage you need a big magnet( the field). Most generators use an electro-magnet. Now the electro-magnet needs a source of power (electricity). We could use the generators own output to excite the field (magnet), this is called self excitation. The problem with self excitation is that we have to wait for the generator to turn and start generating, also to start generating (Building up) there must be some left over magnetism from the last time it was run (called residual magnetism) or not even a little voltage will be generated to start the field current flowing. To solve these problems we could use separately excited. This means we must have a separate source of power to excite the field to produce the magnetism. Sometimes a battery or gasoline driven generator is used to excite the field of a very large generator to get it generating and then we can use some of the generated output to either recharge the battery or switch over to from the battery. In any case we have adjustable control of the generator all the time. This is why most generators are designed to be separately excited. And that is why you car has a voltage regulator. It wakes up the alternator when the engine is started by separately exciting it (the field) with the battery and then regulates the output voltage of the alternator as the engine changes speed with the driver's commands from the gas pedal.
What is going to happen when you repeat this experiment on self D.C generator?
It is self excited generator, no external excitation circuit.
The value of resistance of shunt field winding beyond which the shunt generator fails to build up its voltage is known as " critical resistance at a given speed it is the maximum field resistance with which the shunt generator excite.
when the current is passing through the winding then it is called "Excitation". Types of excitation (1)seperately excited generator. (2)self excited generator. self generator is classified into 3 types. 1.shunt generator. 2.series generator. 3.compound generator. compoud generator is again classified into 2 types. 1.short shunt generator. 2.long shunt generator.
no residual magnetism in the stator. this can happen with an overload which will occasionally even reverse the output polarity
when the current is passing through the winding then it is called "Excitation". Types of excitation (1)seperately excited generator. (2)self excited generator. self generator is classified into 3 types. 1.shunt generator. 2.series generator. 3.compound generator. compoud generator is again classified into 2 types. 1.short shunt generator. 2.long shunt generator.
self ducing
There are two types me dc generator 1 separately excited dc generator 2 self excited dc generator