Problem 104-7    Source:   Example 5-6 - page 215 - KOTHARY - NAGRATH -    Book: Electric Machine - 4th edition - Ed. McGraw Hill - 2010

A dc generator with lap winding has 4 poles and rotates at 1,600 rpm driven by a motor diesel. The armature has 728 conductors. The generator feeds an electrical load by supplying a current of 100 A. The flux per pole is 0.032 Wb.

a) calculate the electromagnetic power developed by the generator;

b) what torque is provided by the diesel engine.

Solution of the Problem 104-7   

Item a

In this problem we have that the multiplicity is m = 1. Then, the value of a, given by eq. 102-08, is:

Knowing that a = 4, P = 4 and Z = 728, we can calculate the constant K_a through eq. 102-14, or:

To find the value of E_A we will use the eq. 102-13. Soon:

Therefore, the electromagnetic power of the generator is given by eq. 103-17, or:

Item b

In this item we must calculate the angular velocity of the machine.

To calculate the torque of the diesel engine we will use the eq. 103-18, after a little algebraic arrangement.