| 摘要 |
A reversible electric motor drive is provided, which comprises a motor 2, at least one direction control contactor 13, 14 and a monitoring circuit for detecting incorrect operation of the contactor. The motor is provided with two signal output terminals D1, D2, which carry different voltages in dependence on the sense of rotation. At least one additional signal output terminal e.g. 35 is connected to the contactor(s) and carries different voltages in dependence on the setting of the mechanism R1 for actuating the contactor(s). A comparator 45 detects whether the additional signal output terminal 35 delivers a signal which corresponds to or differs from the signals delivered by the signal output terminals D1, D2 connected to the motor. In response to this comparison a switching signal is generated, which acts at least to de-energize the motor when the signals do not correspond. <IMAGE> |
