| 摘要 |
<p>419,614. Master control of D.C. motors. ENGLISH ELECTRIC CO., Ltd., 28, Kingsway, London, CALDBECK, C. J., Woodcot Avenue, Ferniehurst Park, Baildon, Yorkshire, and MARTIN, J., 31, Southern Parade, Frenchwood, Preston, Lancashire. May 29, 1933, No. 15461. [Class 38 (iii).] Reversing.-Switches used for connecting resistance in shunt with the field of a series motor driving, for example, a vehicle, are employed also for making connections for reverse operation. With a reversing switch 22-25 in the " forward " position, operation of a master controller 14-21 causes in succession closure of line contactors 5, 6, exclusion of steps of armature resistance 3, and connection of field shunting resistances 12, 13. With the switch 22-25 in the " reverse" position, operation of the master controller to its first position causes closure of line contactor 6 and series field shunting contactors 10, 11, the field being thus reversed, and the motor running in the reverse direction at slow speed. Further movement of the master controller may be prevented by a mechanical interlock, or an electrical interlock preventing the closure of armature resistance contactor 7 may be provided, and then further movement of the master controller cuts out two steps of armature resistance in turn to give a higher and variable reverse speed.</p> |
