| 摘要 |
PURPOSE:To improve the ventilation effect by measuring the condenser voltage for a ventilation fan, and regulating the opening of air intake to a room. CONSTITUTION:By turning on a switch 2, a condenser motor 1 is electrified to operate a ventilation fan. When the ventilation fan is operated in an air-tight room, the air pressure drops and there will be a low load on the condenser motor 1. As a result, its speed becomes greater to increase the voltage across the terminals of the condenser 4. The incremental difference of voltage across the terminals between the air-tight condition and not air-tight condition is measured by a determining circuit 5, which sends out a signal to an output circuit 6 which in turn outputs a voltage in proportion to the voltage differential to a regulator 7. The regulator 7 regulates the opening of air intake in proportion to the voltage. Therefore, the pressure drop in the room is cancelled, allowing adequate ventilation.
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