Analysis of Transistor Motor on Torque Characteristics

Abstract

A motor whose magnet rotor is driven by the exciting current controlled by the switching action of semiconductors, is going to be utilized in several eqipments. The motor in this paper is one of those driving current is controlled by the e.m.f. by the magnet rotor, and is applied on a VTR, a facsimile and so on.
It is necessary to know the characteristics of the speed variation in order ot analyse the relation between the distortion of the reproduced picture and the motor specification. The author analysed the instantaneous torque and its variation in case that (1) the constant of magnetic coupling between driving and controlling winding is equal to unity, (2) holonomic representative machine is applied, (3) balanced push-pull driving by a pair of transistors is used, (4) the speed variation is satisfactorily small comapared with its average speed.
Those characteristics are shown in the range of realizable normalized parameters. The reaction torque resulting from its salient pole structure is described in the geometrical parameters of the magnetic circuits. The analytical inspection of the speed variation and the distortions of the reproduced picture is effectively done after the above discussion.