Control of Large D-C Motors Supplied from Ignitron Rectifiers

From a consideration of the problems of the control of a d-c motor supplied from a phase controlled ignitron rectifier we have tried to show: 1. The closed loop or feed-back system is highly desirable. 2. Such a system requires the use of some form of amplifier between the reference and comparison circuit and the ignitron phase shift system. 3. Three different systems involving the use of amplidynes, electronic amplifiers, and amplistats have been successfully built to serve this function. 4. The choice of the best method for a particular application depends upon the particular requirements of that application.