Electrical Machines What is the necessity of copper brushes in a dc motors? To absorb the mechanical shocks produced during running condition. To convert alternating supply current to direct current. None of these. To increase the flux cutting by the rotor. To absorb the mechanical shocks produced during running condition. To convert alternating supply current to direct current. None of these. To increase the flux cutting by the rotor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines An ideal synchronous motor has no starting torque because rotor winding is highly reactive. relative velocity between the stator and rotor mmf’s is zero. rotor is made up of salient poles. relative velocity between stator and rotor mmf’s is not zero. rotor winding is highly reactive. relative velocity between the stator and rotor mmf’s is zero. rotor is made up of salient poles. relative velocity between stator and rotor mmf’s is not zero. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A DC Shunt Motor having shunt field resistance of 250 Ω and armature resistance of 0.5 Ω is connected to 250 V supply and load current of 21 A. What is the back emf generated ? 150 V. 240 V. 230 V. 210 V 150 V. 240 V. 230 V. 210 V ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, the field system has to be provided on stator unlike synchronous machines Where in it could be on any member, because dc machines are comparatively low rating machines. it gives more uniform air-gap flux distribution commutator action is not possible otherwise it reduces field structure iron losses dc machines are comparatively low rating machines. it gives more uniform air-gap flux distribution commutator action is not possible otherwise it reduces field structure iron losses ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines No load test of 3-phase induction motor gives which of the following? None of these constant loss variable loss both A and B None of these constant loss variable loss both A and B ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Synchronous condensers are used to reduce hunting improve starting torque improve the power factor All of these reduce hunting improve starting torque improve the power factor All of these ANSWER DOWNLOAD EXAMIANS APP
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