| 摘要 |
A combination solid state voltage sensing and timing relay employed for disconnecting equipment from a line source when the line voltage drops below a preset voltage for a preset time period. Whereas the pick up voltage of the voltage sensor is fixed at a first level, the drop out voltage is adjustable by means of a variable resistance element to be at a value lying within a range which is just slightly below the pick up voltage at the top of the range to a value which is significantly below the pick up voltage. The time delay interval is adjustable by way of a second variable resistance over a range of the order of from 0.5 to 10 seconds. The output of the undervoltage timer is a single pole normally open solid state switch for selectively connecting or disconnecting the line source from the load, depending upon the condition from the source and the length of time during which this condition persists.
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