Transistorized Motor Speed Controls for Satellite Tape Recorders

The proposed paper discusses the problems arising in the design of an ac transistorized power supply for low power synchronous motors used in satellite recorders. It treats a current design for a specific satellite application, presents the design of the over-all system, and states alternate methods that can be used. The paper also discusses the over-all system parameters which must be considered in the choice of a hysteresis synchronous motor, the motor´s operating frequency, and its characteristics. Also treated in the paper is a transistorized dc motor control used in a Signal Corps tape recorder. It discusses the servo loop used to accomplish the control of speed, and the accuracy that may be obtained. Diagrams of the exact circuit are presented and analyzed so that the reader may apply the technique to his future needs. The relative advantages and disadvantages of the dc motor and ac synchronous motor in the low-power output range are discussed. The system is designed to meet the environment of the satellite package. The emphasis is on a system requiring a minimum of power consumption and smallest possible size and weight, with no sacrifice of reliability or performance.