| 摘要 |
519,465. Control of D.C. motors. GENERAL ELECTRIC CO., Ltd., and TURRALL, J. C. Oct. 17, 1938, No. 29999. [Class 38 (iii)] In a series-parallel traction equipment, more particularly a 1,500 or 3,000 volt system, the ends of the bridge circuit adjacent the 'supply are connected to a resistance 18, the mid-point of which is connected to the supply through timeswitches 7, 8. At starting contactor 13 is closed then time-switches 7, 8 and immediately afterwards line switch 9. Parallel operation is given by closing line switches 10, 11, opening contactor 13 and closing contactor 12. The motor circuits are opened by opening switches 9, 10 and then switches 7, 8, 11. In one modification the line-switch 8 is transferred to one arm of the bridge so as to correspond to the switch 11, and in another modification the line-switch 9 is direct across one half of the resistance 18. |
