The synchronous speed for the seventh space harmonic $$mmf$$ wave of a $$3$$-phase, $$8$$ pole, $$50$$ $$Hz$$ induction machine is

Two $$3$$-phase, $$Y$$-connected alternators are to be paralleled to a set of common bus bars. The armature has a per phase synchronous reactance of $$1.7\Omega $$ and negligible armature resistance. The line voltage of the first machines is adjusted to $$3300$$ $$V$$ and that of the second machine is adjusted to $$3200$$ $$V.$$ the machine voltages are in phase at the instant they are paralleled. Under this condition, the synchronizing current per phase will be

A $$4$$-pole, $$3$$-phase, double layer winding is housed in a $$36$$-slot stator for an $$ac$$ machine with $$60$$ degree phase spread. Coil span is $$7$$ slot pitches. Number of slots in which top and bottom layers belong to different phases is.

The flux per pole in a synchronous motor with the field circuit ON and the stator disconnected from the supply is found to be $$25$$ $$mWb.$$ When the stator is connected to the rated supply with the field excitation unchanged, the flux per pole in the achine is found to be $$20$$ $$mWb$$ while the motor is running on no load. Assuming no load losses to be zero, the no load current down by the motor from the supply