| 摘要 |
525,451. Electric motor control systems. BRITISH THOMSON-HOUSTON CO., Ltd. Feb. 21, 1939, No. 5777. Convention date, Feb. 22, 1938. [Class 38 (iii)] To prevent damage to the motor, due to brush sparking or flashing over at the commutator, when an electric vehicle runs over points or the bow jumps, the field-coils of the north poles are formed into a group and the fieldcoils of the south poles are formed into another group, and an ohmic or inductive resistance is connected in parallel with one of the seriesconnected groups, preferably the earthed group. |
