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Why terminal voltage of the self-excited shunt generator lower than that of the separately excited shunt generato?
Some generators are self excited; this means their terminal voltage is fed back to the excitation system to supply power to the rotor of the generator (which makes it into an electromagnet); the more power that is fed back, the stronger the electromagnet becomes, which makes it harder to turn the generator, which causes the generator to push out more power (simplified, really quick version). If there is a fault electrically near the terminal of a self excited generator, the terminal voltage will sage to near zero; this means the voltage supplied to the excitation system will drop by the same percentage (say the terminal voltage is 30% of what it should be, then the maximum supplied voltage to the excitation system drops to 30% of what it normally is, since P = V*I). Since the input power is less, the output of the generator will decrease (current will decrease). The terminal voltage is determined by the impedance between the generator and the fault such that V = I*Z; As I decreases, V will also continue to fall, causing the terminal voltage to sag even more. A non-self excited generator gets its' excitation power from the grid, specifically from a location that is electrically separated from its' terminal voltage. If the terminal voltage sagged to 30% (same fault location as above example), the excitation system voltage may be impacted slightly (say 2%) so the excitation system power is near maximum (98% for this example). Since the excitation system is much farther removed from the terminal voltage, it is not dependent upon it, thus the terminal voltage will not continue to sag as with a self excited system.
How do we adjust the voltage of a shunt generator?
The voltage is adjusted with a potentiometer that adjusts the field voltage through the voltage regulator.
Can you use the separately excited shunt generator machine as self excited generator?
You have a seperately excited generator and then you have a shunt generator which has the field winding in parallel with the armature terminals. In DC machines a separately excited generator could be run as a shunt generator provided the field winding is designed to work on the generated voltage. A separately excited alternator needs a DC supply for the field winding. In car alternators that is taken from the main winding via a rectifier and a voltage regulator.
What are the differences of Long shunt vs short shunt generator?
In long shunt the shunt field winding is in parallel to both generator and series field. In short shunt the shunt field is in parallel to generator only.
Can you use a compound generator as a booster why?
Yes, a compound generator can be used as a booster because it has both series and shunt windings, allowing it to maintain voltage stability under varying load conditions. The series winding increases the output voltage in response to increased load, while the shunt winding provides a stable base voltage. This combination enables the generator to compensate for voltage drops, effectively boosting voltage when needed in electrical systems.
Why terminal voltage of a self excited shunt generator decreases with an increase of load?
The terminal voltage of a self-excited shunt generator decreases with an increase in load due to an increase in voltage drop across the internal resistance of the generator. As the load current increases, the drop across the internal resistance also increases, reducing the output voltage available at the terminals. This effect is known as voltage regulation and is a common characteristic of self-excited shunt generators.
Why terminal voltage of the self-excited shunt generator lower than that of the separately excited shunt generato?
Some generators are self excited; this means their terminal voltage is fed back to the excitation system to supply power to the rotor of the generator (which makes it into an electromagnet); the more power that is fed back, the stronger the electromagnet becomes, which makes it harder to turn the generator, which causes the generator to push out more power (simplified, really quick version). If there is a fault electrically near the terminal of a self excited generator, the terminal voltage will sage to near zero; this means the voltage supplied to the excitation system will drop by the same percentage (say the terminal voltage is 30% of what it should be, then the maximum supplied voltage to the excitation system drops to 30% of what it normally is, since P = V*I). Since the input power is less, the output of the generator will decrease (current will decrease). The terminal voltage is determined by the impedance between the generator and the fault such that V = I*Z; As I decreases, V will also continue to fall, causing the terminal voltage to sag even more. A non-self excited generator gets its' excitation power from the grid, specifically from a location that is electrically separated from its' terminal voltage. If the terminal voltage sagged to 30% (same fault location as above example), the excitation system voltage may be impacted slightly (say 2%) so the excitation system power is near maximum (98% for this example). Since the excitation system is much farther removed from the terminal voltage, it is not dependent upon it, thus the terminal voltage will not continue to sag as with a self excited system.
What cause the voltage drop in shunt generator when its loaded?
because the voltage likes to drop
How do we adjust the voltage of a shunt generator?
The voltage is adjusted with a potentiometer that adjusts the field voltage through the voltage regulator.
Theory for load test on dc shunt generator?
load test on dc shunt generator is a test to plot the internal and external characteristics of the generator.
How compound generator operates?
It works with two reactor coils for excitation of the field reactor coil , which in turn provides current to the field. The two reactor coils are connected in shunt and series with the output of the generator stator or armature ( from where load is connected).
What is critical resistance of the field circuit of a DC generator?
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.
Can you use the separately excited shunt generator machine as self excited generator?
You have a seperately excited generator and then you have a shunt generator which has the field winding in parallel with the armature terminals. In DC machines a separately excited generator could be run as a shunt generator provided the field winding is designed to work on the generated voltage. A separately excited alternator needs a DC supply for the field winding. In car alternators that is taken from the main winding via a rectifier and a voltage regulator.
What are the differences of Long shunt vs short shunt generator?
In long shunt the shunt field winding is in parallel to both generator and series field. In short shunt the shunt field is in parallel to generator only.
Can you use a compound generator as a booster why?
Yes, a compound generator can be used as a booster because it has both series and shunt windings, allowing it to maintain voltage stability under varying load conditions. The series winding increases the output voltage in response to increased load, while the shunt winding provides a stable base voltage. This combination enables the generator to compensate for voltage drops, effectively boosting voltage when needed in electrical systems.
If the speed of the dc shunt motor falls due to loading what will be the effect?
on adding load on a dc shunt motor, the amount of current and torque will increase. but terminal voltage will decrease
What would happen if a shunt-excited DC generator was operated at too low a speed?
A shunt generator is a type of DC generator that does not use a permanent magnet. Reducing the speed of the generator will reduce the output, but not the load the generator requires because the currents in the parallel branches are independent.
