| 摘要 |
The motor (1) comprises an armature (1a), field winding (1b) and interpole (1c). For the braking condition the armature is connected to a fixed loading resistance (2), and the field shunt connected with a chopper circuit (3) in series with the winding which is also bridged by a free wheel diode (4). Auxiliary ballast resistors (5, 6, 7) may be included if necessary. - Control of the braking effort is by variation of the mark-space ratio of the chopper. Thus at high machine speeds the current flow through the field is of short duration, but increases as the speed falls until the resistive load (2) is virtually short circuited. The control is free from contactors, and contains no capacitors which could be the source of unwanted oscillations or resonance.
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