| 摘要 |
857,332. Control of D.C. motors. ENGLISH ELECTRIC CO. Ltd. Dec. 5, 1957 [Sept. 12, 1956], No. 27848/56. Class 38 (3). [Also in Group XXXV] The direct voltage applied to a load such as motors M1, M2 from an A.C. supply 11 through electrode controlled rectifiers such as the bridge arrangement of ignitrons I1, I2, I3, I4, is varied by altering consecutively the control voltage applied to the rectifier electrodes and the alternating voltage applied to the rectifier anodes. When energizing the motors from the zero voltage position by moving a controller, an igniter pulse source 18 is so operated that the igniter pulses are advanced in phase to the maximum igniter voltage position, after which the controller varies the output of supply transformer 10 by operating on load tap changing mechanism. In the low voltage position tapped windings 10c, 10d buck the respective halves of centre-tapped winding 10b. The contactor successively operates contacts T1-T5 and TT1-TT5 in conjunction with the shorting contactors P, PP across auto transformers 13, 14 until the buck is zero. The contacts of change-over switches 15, 16 are then operated so that when further movement of the controller operates the tap switches, windings 10c, 10d boost winding 10b by an increasing amount. The tapped secondary windings 10c, 10d may be replaced by an induction regulator, and the rectifiers may be of the excitron type. |
