30 Reservoir Circuit

Reservoir Control Circuit

A three-position selector switch is again used to provide either manual or automatic control. When the selector switch is moved to the AUTO position, the magnetic starter is controlled by the opening or closing of the float switch contacts, similarly to the sump-pump circuit previously discussed.

The key change is in the nature of the switches contacts. For a tank-fill circuit, our float switches will have their contacts wired normally closed. This means that both switches will close at a low liquid level and open at a high level. Also note that auxiliary motor contact is now in parallel with FS 2 or the low-level switch. This ensures that the motor starts pumping liquid into the tank when it’s nearly empty and doesn’t stop until the high-level switch is opened.

Again, with two pilot devices, our circuit has a greater range of sensitivity than it would with only a single float switch.



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Basic Motor Control Copyright © 2020 by Aaron Lee and Chad Flinn is licensed under a Creative Commons Attribution 4.0 International License, except where otherwise noted.

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