摘要 |
A system for controlling the transmission of electrical power between a D.C. power source and a load. The system includes a circuit having indicator lamps for visually indicating the polarity of the power source and of the load. Relays are utilized to prevent power transmission when the source and the load are improperly connected to the circuit. The circuit includes normally closed contacts of one relay in series with the coil thereof and a resistor in parallel with the normally closed contacts so that when the coil is energized, the voltage applied to the coil is automatically reduced during operation.
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