Electrical Machines With the increase in speed of DC motor Both back emf as well as line current fall. Both back emf as well as line current increase. Back emf falls and line current increase. Back emf increase but line current falls. Both back emf as well as line current fall. Both back emf as well as line current increase. Back emf falls and line current increase. Back emf increase but line current falls. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Armature reaction in dc motor results short circuit. decrease in speed. increase in speed. open circuit. short circuit. decrease in speed. increase in speed. open circuit. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Two 3-phase AC generators are such that one has twice the linear dimensions of the other. The field windings of each are excited to give identical sinusoidal air-gap flux density waveform. Both have the same number of stator slots and identical winding patterns. The conductor/slot in a big generator is K times that of the smaller one. The value of K to get equal no load voltage at same frequency is 4. 1/2. 1/4. 8. 4. 1/2. 1/4. 8. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The armature mmf in a dc machine is 1. stationary with respect to field poles 2. stationary with respect to armature 3. rotating with respect to field poles 4. rotating with respect to armature From these, the correct answer is 2, 4 2, 3 1, 4 1, 3 2, 4 2, 3 1, 4 1, 3 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The damper windings also called the squirrel cage windings or damper grids both (A) and (B). are provided on the stator for improving power factor. consists of short-circuited copper bars embedded in the field pole faces. are provided in a synchronous motor to make it self starting. both (A) and (B). are provided on the stator for improving power factor. consists of short-circuited copper bars embedded in the field pole faces. are provided in a synchronous motor to make it self starting. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The change in speed of a DC generator due to increased load is corrected by increasing input power of the prime mover. increasing armature resistance. increasing terminal voltage. increasing armature cooling. increasing input power of the prime mover. increasing armature resistance. increasing terminal voltage. increasing armature cooling. ANSWER DOWNLOAD EXAMIANS APP
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