Electrical Machines The residual magnetism of a self-excited dc generator is lost. To build up its emf again the armature connection must be reversed the field winding connection must be reversed field winding must be excited by low voltage dc supply the field winding must be replaced the armature connection must be reversed the field winding connection must be reversed field winding must be excited by low voltage dc supply the field winding must be replaced ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines A 4-pole DC generator runs at 1500 rpm. The frequency of current in the armature winding is: 100 Hz. Zero Hz. 25 Hz. 50 Hz. 100 Hz. Zero Hz. 25 Hz. 50 Hz. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In dc machines, 1. reactance voltage is proportional to armature current 2.reactance voltage is proportional to core length 3.reactance voltage is due to self-flux of the coil undergoing commutation 4. armature-cross flux is neutralized by interpolar flux 5. interpolarmmf is more than armature mmf in the interpolar zone From these, the correct answer is 2, 3, 4 1, 2, 3, 4 1, 2, 5 1, 3, 5 2, 3, 4 1, 2, 3, 4 1, 2, 5 1, 3, 5 ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines In a DC machine the armature mmf is rotating with respect to field poles. rotating with respect to field poles as well as armature. stationary with respect to field poles. stationary with respect to armature. rotating with respect to field poles. rotating with respect to field poles as well as armature. stationary with respect to field poles. stationary with respect to armature. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines Ratio of starting torque to full load torque is minimum in Differential compound motor. Cumulative compound motor. Shunt motor. Series motor. Differential compound motor. Cumulative compound motor. Shunt motor. Series motor. ANSWER DOWNLOAD EXAMIANS APP
Electrical Machines No load saturation characteristics are plotted between no load voltage and armature current no load voltage and field current short circuit current and armature current short circuit current and field current no load voltage and armature current no load voltage and field current short circuit current and armature current short circuit current and field current ANSWER DOWNLOAD EXAMIANS APP
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