Question

An electric generator delivers a load current of 24A at a terminal voltage of 250v. The generator is driven by a motor,whose output Power is 7.5kw. What is the efficiency of the generator?

Answer 1

The power given into the load is:

$$P_{actual} = UI = 250V\cdot 24A = 6000W = 6.0kW$$

The power obtained from the motor is:

$$P_{obtained} = 7.5kW$$

By definition, the efficiency of the generator is

$$\eta = \dfrac{P_{actual}}{P_{obtained}}\times 100\% = \dfrac{6.0kW}{7.5kW}\times 100\% =80\%$$

Answer. 80%.