| 摘要 |
PURPOSE:To prevent the welding of a contact for an AC-DC switching relay by the discharge currents of a smoothing capacitor by connecting the smoothing capacitor so as to short-circuit an output terminal for a rectifier on the outside of a contact on the AC side of a switching means for an armature circuit. CONSTITUTION:An armature 1 for a cam-shaft operating motor is supplied normally with electricity by a DC power supply through an AC-DC switching relay 4 and DC-side contacts 4a, 5a, 6a for relays 5, 6. When the power supply for the cam-shaft operating motor is changed over to the rectifier side from the DC side, DC side contacts 5a, 6a, 6c for the relays 5, 6 are opened while AC side contacts 5b, 6b are closed. A contact 4c for the AC-DC switching relay 4 is changed over to an AC-side contact 4b. A smoothing capacitor 2 for a rectifier 7 is connected between both terminals 7a, 7c for the rectifier 7 on the outsides of the AC-side contacts 5b, 6b for the relays 5, 6, thus preventing a welding by the discharge currents of the smoothing capacitor 2 of the contact for the AC-DC switching relay.
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