The bridge circuit shown in the fig below is used for the measurement of an unknown element Z_x. The bridge circuit is best suited when Z_x is a

The direct axis and quadrature axis reactances of a salient pole alternator are $$1.2$$ $$p.u$$ and $$1.0$$ $$p.u$$ respectively. The armature resistance is negligible. If this alternator is delivering rated $$kVA$$ at $$upf$$ and at rated voltage then its power angle is

A three-phase, salient pole synchronous motor is connected to an infinite bus. It is operated at no load a normal excitation. The field excitation of the motor is first reduced to zero and then increased in reverse direction gradually. Then the armature current

A 220 V, DC shunt motor is operating at a speed of 1440 rpm. The armature resistance is 1.0 $$\Omega$$ and armature current is 10 A. of the excitation of the machine is reduced by 10%, the extra resistance to be put in the armature circuit to maintain the same speed and torque will be