Electrical Machines
A synchronous machine has P number of poles, find the relation between electrical angular momentum (ωe) and mechanical angular momentum (ωm)?

 ωe = 2/P*ωm
 ωe = P/2*ωm
 ωe = ωm
 ωe = P*ωm

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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 winding was wrongly connected
 there was no residual magnetism in the field circuit
 there was a break in the armature circuit
 field resistance was higher than critical resistance

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