| 摘要 |
An electronic reversible motor operated valve assembly adapted to be controlled by a two-wire thermostat. The assembly includes a valve casing having a pivotally mounted valve member, and a reversible motor drive unit having forward and reverse motor windings which, when alternately energized, effect pivoting of the valve member between closed and open positions to control fluid flow through the valve casing. The assembly includes a triac having a first annode and a gate coupled across the two wires of the thermostat, and having a second annode and the gate coupled across separate end terminals of the motor windings. Commonly connected end terminals of the motor windings and the first annode of the triac are coupled to an A/C power source to afford biasing the triac. When the thermostat switches to an off state, the triac is biased on and the reverse motor winding is energized to pivot the valve to the open position. When the thermostate switches to an on state, the triac is biased off and the forward motor winding is alternately energized to pivot the valve to the closed position.
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