| 摘要 |
The reversible electric motor drive is for household appliances, and has an alternating current drive motor and a reversing switching arrangement, depending on load. The switching arrangement is pref. a switching relay, controlled by a thyristor, whose contacts are used for changing over the drive motor, at least approximately at the extreme value of a half wave of the alternating voltage. The change-over takes place via a circuit for the motor reverse run. A diode (14) is incorporated in this circuit which blocks half waves of opposite polarity, which follow the change-over pulse. In this manner contact chatter at high current strength, with harmful effects, is prevented by a simple circuit which also prevents arcing and welding of the relay contacts. |
