question_answer

Electrical efficiency of a DC motor is equal to which of the following expressions?

A)  \[\frac{\text{Output}\,\,\text{power-Input}\,\,\text{power}}{\text{Input}\,\,\text{power}}\]

B)  \[\frac{\text{Input}\,\,\text{power-Copper}\,\,\text{loss}}{\text{Input}\,\,\text{power}}\]

C)  \[\frac{\text{Input}\,\,\text{power-Total}\,\,\text{losses}}{\text{Input}\,\,\text{power}}\]

D)  None of the above