Critical resistance is that resistance which is higher then the shunt field resistance. If the critical resistance is not higher then the shunt field resistance the generator is not possible to build up voltage.
After drawing OCC curve, Then tangent is drawn to its initial portion. The slope of the curve gives the critical resistance.
The value of the resistance represented by the tangent to the curve is known as critical resistance for a given speed.
USES OF DC GENERATOR:
1. Shunt generator with field regulator are used for ordinary lightening and power supply.
2. Series generators are not used for power supply because of the rising characteristics. Used in distribution system particularly in Railway scurvies.
3. Compound wound generator is the most widely used DC generator. Because its external characteristics used in motor driven widely.
Q: Justify your logic a series generator is not widely used in power supply?
ANS:
Because there is too much losses i.e. armature loss. So that voltage loss is high.
After drawing OCC curve, Then tangent is drawn to its initial portion. The slope of the curve gives the critical resistance.
The value of the resistance represented by the tangent to the curve is known as critical resistance for a given speed.
USES OF DC GENERATOR:
1. Shunt generator with field regulator are used for ordinary lightening and power supply.
2. Series generators are not used for power supply because of the rising characteristics. Used in distribution system particularly in Railway scurvies.
3. Compound wound generator is the most widely used DC generator. Because its external characteristics used in motor driven widely.
Q: Justify your logic a series generator is not widely used in power supply?
ANS:
Because there is too much losses i.e. armature loss. So that voltage loss is high.