Analysis of a Half-Cycle-Response Magnetic Amplifier with Resistance or A-C Servomotor Load

Half-cycle-response magnetic amplifiers suitable for controlling 2-phase servomotors have been studied by many authors. In particular, Geyger and Kallander suggested a full-wave push-pull circuit which resulted in superposing the fundamental frequency voltage on unidirectional voltage across the control winding, helping to stabilize those servomotors which have a low ratio of effective viscous friction to inertia. This paper considers a modification of these circuits for both resistance and motor loading. The modification results in an improved amplification factor and the motor loaded circuit is analyzed for both stand-still and running conditions, taking into account the generated voltage of the motor and variable extinction angle. Analysis is then verified by experimental data.