| 摘要 |
1,123,022. Control of D.C. motors. RANSOMES SIMS & JEFFERIES Ltd. 10 March, 1966 [12 March, 1965], No. 10608/65. Heading H2J. [Also in Division H3] In a system for controlling the speed of a D.C. motor 1, e.g. in a battery-electric vehicle, by varying the on/off ratio of a continuously pulsed thyristor 9, the thyristor is turned off by the discharge of a capacitor 27 through a second thyristor 29, the charge on the capacitor being reversed during the conduction of the first thyristor by the operation of a third thyristor 35. The sequence is as follows: (i) 29 is triggered to conduct until capacitor 27 reaches battery potential V; (ii) 9 is triggered, energizing motor 1 and connecting batteryve to capacitor +ve plate causing the other plate to go -V; (iii) 35 is triggered, discharging capacitor forwardly through 9 and an inductor 37, which recharges the capacitor in the reverse direction to about + 3V; (iv) 29 is again triggered and the capacitor discharges, cutting off 9, and then is recharged by the battery to repeat the sequence. Triggering is effected by a multivibrator 47 of adjustable frequency, but thyristor 35 may be triggered according to the charge on capacitor 27. In alternative circuits (Figs. 2, 3, not shown) the voltage on the capacitor is limited by battery tapping or a resistor in series with the inductor and in Fig. 4 (not shown) the inductor is replaced by a resistor, the inductance of the battery being utilized. |
