A moving iron ammeter produces a full scale torque of $$240$$ $$\,\mu Nm$$ with a deflection of $${120^ \circ }$$ at a current of $$10$$ $$A$$. The rate of change of self inductance $$\left( {\mu H/radian} \right)$$ of the instrument at full scale is

A galvanometer with a full scale current of $$10$$ $$mA$$ has a resistance of $$1000$$$$\Omega $$. The multiplying power (the ratio of measured current to galvanometer current) of a $$100$$$$\Omega $$ shunt with this galvanometer 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 hydraulic turbine having rated speed of $$250$$ $$rpm$$ is connected to a synchronous generator. In order to produce power at $$50$$ $$Hz,$$ the number of poles required in the generator are