| 摘要 |
An electronic overload relay has an intrinsic power supply connected in parallel with the NC contact of the relay between wire attachment terminals. The power supply is parallel connected zener diode and capacitor, connected to the processor in parallel with a low voltage sensing circuit that detects the charge on the capacitor, whereby the processor operates to turn on a unijunction transistor for low voltage coil applications to shunt the power supply during contactor closing and turn off a predetermined interval later by which time the contactor should have closed.
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