Problem 103-6    Source:  Problem prepared by the website author.

A DC motor in series configuration consumes a current of 15  A when powered by a voltage of 220  V. If the armature resistance is equal to 0.75  Ω and the stator resistance is 0.55  Ω, find the value of the electromotive force E_A.

Solution of the Problem 103-6   

The series configuration of a DC motor is characterized by the circuit shown in Figure 103-6.1.

The equation according to Kirchhoff's law for the series motor is given by eq. 103-31, reproduced below.

Making an algebraic arrangement in the above equation, we find the value of the electromotive force, or:

Substituting for numerical values ​​and performing the calculation, we find: