Electrical Machines Copper brushes in DC machine are used where low voltage and high currents are involved. None of these in both of above cases. where high voltage and low current. where low voltage and high currents are involved. None of these in both of above cases. where high voltage and low current. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines The maximum possible speed at which an alternator can be driven to generate 50 Hz and 4000 V is 4000 rpm. 3600 rpm. 1500 rpm. 3000 rpm. 4000 rpm. 3600 rpm. 1500 rpm. 3000 rpm. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A self-excited shunt generator fails to build up, because 1. the field circuit is open 2. The armature circuit is open 3. the residual magnetism is absent 4. The direction of rotation is wrong From these, the correct answer is 1, 2, 3 and 4 1, 3 1, 2 and 3 3 only 1, 2, 3 and 4 1, 3 1, 2 and 3 3 only ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines As compared to DOL starting, a cage induction motor with star-delta starting shall have reduced starting current. more starting torque. smoother acceleration. more starting time. reduced starting current. more starting torque. smoother acceleration. more starting time. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines To eliminate 5th harmonic in the induced voltage phase breadth should be 18° 72° 36° 30° 18° 72° 36° 30° ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a stepper motor the detente torque means minimum of the static torque with the phase winding excited. minimum of the static torque with the phase winding unexcited. maximum of the static torque with the phase winding excited. maximum of the static torque with the phase winding unexcited. minimum of the static torque with the phase winding excited. minimum of the static torque with the phase winding unexcited. maximum of the static torque with the phase winding excited. maximum of the static torque with the phase winding unexcited. ANSWER DOWNLOAD EXAMIANS APP
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