Why generator field rheostat is kept in maximum position?
At the time of starting of motor, the armature resistance is kept at maximum position to control and reduce the high starting current and field rheostat atminimum position to ensure that speed does not go beyond rated value and to have high starting torque.
Why is generator rheostat in maximum position?
SSC Question At the time of starting of motor, the armature resistance is kept at maximum position to control and reduce the high starting current and field rheostat atminimum position to ensure that speed does not go beyond rated value and to have high starting torque.
What is the relation between torque and armature current?
armature current (Ta-Ia) This characteristic is also known as electrical characteristic. We know that torque is directly proportional to the product of armature current and field flux, Ta ∝ ɸ.
Why is rheostat in generator field kept in maximum position at start up?
What is the efficiency of dc motor at maximum power?
Explanation: For getting maximum power, derivative of power with respect to current is equal to 0. This is practically impossible to achieve as, current required is much more than its normal rated value. Large heat will be produced in a machine and efficiency of motor will be less than 50 %.
What is the purpose of a DC generator?
DC GENERATOR The direct current (DC) generator (Dynamo) is only used for special application or local power generation.
What do field Breakers do on a generator?
Field breakers are used to protect both the AC and DC sides of the generator. Power rectifiers convert AC power to DC power. Cooling systems maintain operating temperatures required for reliable operations.
Why is field regulator kept in minimum position for starting DC?
It should be noted that speed of a shunt motor is inversely proportional to the main flux and the main flux is proportional to the field current. If the field regulator is kept at any other position if effects the field current and hence it reduces as the regulator moves from the lower to higher position.
How is the electromagnetic field generated in a generator?
The field flashing equipment is used to generate the initial electromagnetic field until the generator creates enough voltage to self-excite and sustain the mechanical to electrical power conversion.