The dc motor armature is fed from a variable voltage and adjustable polarity supply whose current rating must be ... it possible to easily reverse the generator excitation thereby reversing the voltage polarity for reversal of the direction of rotation of the motor. ... dc supply drawing power from ac mains through a transformer.
|Author||:||D. P. Kothari, I. J. Nagrath|
|Publisher||:||Tata McGraw-Hill Education - 2004|