GATE 2022 : Electrical Machine Quiz 7

For an alternator, at constant field current open circuit terminal voltage and short circuit current are 2000 V and 400 A, respectively. The value of internal voltage drops if load current is I_L is ______ volts.

A 2-pole, 3-phase, 3000 rpm, synchronous generator has 48 slots. Each has two conductors in a double layer winding. The coil pitch is 17 slots. Each phase winding has two parallel paths. Calculate the flux/pole required to generator phase voltage of 1400 V.

A 3-ϕ, salient pole alternator has direct axis reactance of 0.5 pu and quadrature axis reactance of 0.2 pu, when its terminal voltage is 1.0 pu, excitation voltage is 1.2 pu. To deliver maximum power, the rotor angle should be ______ degree.

A single-phase alternator of rotor 2000 V has armature resistance and reactance of 0.8 and 4.94 Ω respectively. The voltage regulation of the alternator at 100 A load and 0.8 leading power factor is X%. Then the value of X is _________.

A 3ϕ, 50 Hz, 4 Pole Alternator has a star connected winding with 72 slots and 12 turn per slot. The Flux per pole is 0.05 Wb. The Generated line emf is.

A 3- 400V, 50 Hz Y connected synchronous motor takes 50 kW at 400 V, the power factor is 0.6 lag. If the induced emf is increased by 50% by keeping the input power constant, then new power factor will be ________ (synchronous reactance of machine is 2 Ω/Ph)