| 摘要 |
<p>1,122,678. Control of A.C. motors. SPERRY RAND CORP. 22 Dec., 1965 [4 Jan., 1965], No. 54343/65. Heading H2J. An induction motor 56, which drives a pair of gyroscopic bearings in opposite directions with respect to each other, is periodically reversed by means of a relaxation oscillator 11 associated with silicon controlled rectifier 32 which is repeatedly switched on and off by alternate pulses from the oscillator. The timing of the oscillations is controlled by the network comprising resistor 60 and capacitor 7. A square wave signal is developed at junction 62, transistor 38 operating as a bi-stable switch which is turned on and off depending upon the state of the rectifier 32. The transistor 38 forms part of an A.C. bridge 40 which is unbalanced in one or the other direction to develop an output voltage across secondary winding 54. This voltage is amplified in amplifier 55 to drive the induction motor in a clockwise or counterclockwise direction according to the sense of unbalance of the bridge.</p> |
