| 摘要 |
<p>960,992. Automatic speed control. TEXAS INSTRUMENTS Inc. Dec. 31, 1962 [Sept. 10, 1962], No. 49029/62. Heading G3R. [Also in Divisions H2 and H3] A series motor 14, 15, is connected to a source of full-wave rectified current through controlled rectifier 16 supplied with gating pulses by discharge of capacitor 21 through the emitter and a base of a unijunction transistor 20. The triggering voltage of the transistor 20 is dependent upon the bias between the first and second bases thereof, this bias being established by the voltage across Zener diode 17. The rate of charge of the capacitor is determined by resistors 22, 23, and the back-E.M.F. of the motor. If the resistor 22 is set at a low value and the motor speed is low, firing will occur early in the half cycle, whilst high resistance in the charging path or high speed will retard firing. A diode 24 shunts series field winding 14 to maintain a back-E.M.F. across the armature.</p> |
