| 摘要 |
A Time Demand Counter permits a sensor to be mechanically coupled, by quick connect/disconnect means, to the power feed line of a monitored device with little disruption of the power feed circuitry. The sensor is nonloading in that essentially no energy is drawn from the monitored device's feed line to power the Time Demand Counter. Unlike current transformers previously used, the sensor does not have to be varied to complement the current drawn by the monitored device. A long useful battery life is assured for internally powered embodiments of the invention. Also, since the invention accumulates the record of ON/OFF cycles, as well as the total accumulated demand time, the average time the monitored device is used each time demand is placed on it can be readily determined.
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