| 摘要 |
873,374. Control of several D.C. motors. ENGLISH ELECTRIC CO. Ltd. April 14, 1959 [April 22, 1958], No. 12811/58. Class 38 (3). In a traction system, the voltage applied to the trailing motors is increased relatively to that applied to the leading motors in order to compensate for the effect of weight transfer between the axles. During forward operation of the vehicle, the motors M1, M3 are the leading motors and the motors M2, M4 are the trailing motors, both groups being connected to a bridge rectifier R1-R4 supplied with variable voltage from a tapped transformer 10. The leading motors are connected directly across the D.C. side of the rectifier, whilst the trailing motors are connected additionally to rectifiers 14, 15, in series. The rectifier 14 increases the voltage applied to the motors M2, M4, by a fixed amount, and the rectifier 15 increases it by an amount dependent upon the position of the tap 13. For reverse operation, the auxiliary voltages are introduced into the circuit of the motors M1, M3. In another arrangement, the two groups of motors are connected to separate bridge rectifiers and are supplied from the main tapped transformer through an auxiliary auto transformer. Tappings in the auto transformer are varied in accordance with the direction of the vehicle so as to maintain the required current differential, Fig. 2 (not shown). In a modification of this arrangement, only one tapping is provided for the auto transformer, and contactors are afforded for reversing the ends of the transformer relative to the two rectifier bridges. |
