| 摘要 |
A separately excited DC motor is arranged to provide operation in a smooth, continuous electrical retarding mode. A series contactor 24 connects the motor armature 10 to a DC power source 14 and is controlled so as to immediately open upon sensing of a need for electrical braking. Concurrently, power to the motor is reversed by H-switch 34a-34d so that no additional changes are required to brake to zero speed. When the speed falls to below a value necessary to maintain the armature voltage above the DC source voltage, the armature is cyclically short-circuited by a switch 26 to boost armature current so that when the short-circuit is removed, the armature reactance forces current to continue for regeneration. The braking operation commences when a microcomputer 44 senses an accelerator 46 has returned to a rest position, a direction switch 48 has been shifted to a neutral position or a brake switch 54 has been actuated.
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