Combined thyratron and tachometer speed control of small motors

MUCH has been done in applying thyratrons to motors.^1–4 This paper is restricted to cases where the speed of the motor is measured by an electric tachometer whose output is used to control the motor input. Since this control is made fast by the use of thyratrons, it is possible to hold the speed of the motor constant under difficult conditions or to vary it rapidly in exact accordance with requirements. Three applications of control of this general type are described together with the methods used. The first application is to a null-type high-speed recorder, the second to a high-speed controller, and the third to a motor generator set held in synchronism with a source of frequency normally constant and at low power level.