Problem 102-5    Source:   Adapted from example 2-1 - page 73 - CHAPMAN, Stephen J. -    Book: Fundamentals of Electric Machines - 5th edition - Ed. McGrawHill - 2013.

We want to obtain a DC machine, 4 poles, which generates an armature voltage E_A = 600 V when operating at speed of 800 rpm, using corrugated winding. The flux at the poles is 0.075 Wb. Find:

a) the machine constant K_a;

b) the number of active conductors, Z, in the rotor.

Solution of the Problem 102-5   

Item a   

To find the value of K_a of the machine we use eq. 102-13 shown below.

After an algebraic arrangement and replacing the variables by their respective numerical values, we find

Item b   

Using the value of the constant K_a and the eq. 102-14, shown below, we can determine the number of active conductors in the rotor, Z.

After some algebraic work on this equation, we get: