Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the field winding must be replaced field winding must be excited by low voltage dc supply the armature connection must be reversed the field winding connection must be reversed the field winding must be replaced field winding must be excited by low voltage dc supply the armature connection must be reversed the field winding connection must be reversed ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The current drawn by the a 230 V DC motor of armature resistance 0.5 Ω and back emf 200 V is 600 660 40 60 600 660 40 60 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The principle of dynamically induced emf is utilized in generator. choke. thermocouple. transformer. generator. choke. thermocouple. transformer. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction of an unsaturated DC machine is none of above. demagnetising. magnetising. crossmagnetising. none of above. demagnetising. magnetising. crossmagnetising. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A dc shunt generator, when driven without any excitation, showed an open circuit voltage of 12 V. When the field winding was excited, the voltage dropped to zero. It happened because field resistance was higher than critical resistance there was no residual magnetism in the field circuit there was a break in the armature circuit field winding was wrongly connected field resistance was higher than critical resistance there was no residual magnetism in the field circuit there was a break in the armature circuit field winding was wrongly connected ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines If the air gap of IM is increased, ____________ will increase. air gap flux. magnetizing current. power factor. speed. air gap flux. magnetizing current. power factor. speed. ANSWER DOWNLOAD EXAMIANS APP
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