Two $$100$$ $$\mu A$$ full scale $$PMMC$$ meters are employed to construct a $$10$$ $$V$$ and a $$100$$ $$V$$ full scale voltmeter. These meters will have figures of merit (sensitivities) as

A current of $$\left[ {2 + \sqrt 2 \sin \left( {314t + 30} \right) + 2\sqrt 2 \cos \left( {952t + 45} \right)} \right]$$ is measured with a thermocouple type. $$5A$$ full scale, class $$1$$ meter. The meter reading would like in the range,

For the given circuit the internal resistance of the ammeters as well as that of the current coil of the wattmeter are zero, and the voltmeters have a very large figure of merit. $${A_1}$$ is a $$6A$$ full scale moving $${\rm I}$$ron type meter. $${A_2}$$ is a commercial full wave rectifier type meter of full scale $$5A$$. $${V_1}$$ is a $$500V$$ meter is an peak response type. $${V_2}$$ is a $$300V$$ $$PMMC$$ type meter and $$W$$ is an electro dynamometer type, $$5A$$, $$230V$$ wattmeter. Determine the readings of $${A_1},$$ $${A_2},$$ $${V_1},$$ $${V_2},$$ and $$W.$$

A separately excited $$DC$$ shunt motor is driving a fan load whose torque is proportional to the square of the speed. When $$100$$ $$V$$ are applied to the motor, the current taken by the motor is $$8$$ $$A,$$ with the speed being $$500$$ $$rpm.$$ At what applied voltage does the speed reach $$750$$ $$rpm$$ and then what is the current drawn by the armature? Assume the armature circuit resistance to be $$1\,\,\,\Omega .$$ Neglect brush drop and mechanical losses.