Question

If a DC compound machine connected as a motor is about to use as a generator, we reverse the series field connections.

(a) True

(b) False

I have been asked this question in an online interview.

Question is from Methods of Excitation topic in portion Commutation Process & Excitation Methods of DC Machines

Answer 1

Right answer is (a) True

To explain I would say: If a dc compound machine connected as a generator is run as a motor, the series field connections must be reversed as the armature current reverses. The motoring action as cumulative/ differential would then be preserved (same as in the generator). This equally applies vice versa – motor to generator.