My building has its sewage flow to a well. In the well, there is an ejection pump lifting the sewage into the next well. The next well has another ejection pump, that lifts sewage again and pumps it into the city system.
Both of these pumps are 10 amp and they are on the same circuit breaker, that is located in a building that I do not own. (I know that it is dumb, but it is what it is). Sometimes this breaker blows when it rains heavily and both pumps operate at the same time. This is a huge hassle.
To fix this situation, I made a controller that I would place inthe upstream well. It would ensure that only one sewage pump runs at any given time. It gives priority to the ownstream pump. When the downstream pump runs, the upstream pump is disabled. The controller has a power relay, (which I found in this lot), as well as a current sensor relay, which senses current going to the downstream pump. It also has lights that illustrate what the controller is doing. It is somewhat watertight. It also has a 2 watt resistor heater inside to drive off any stray humidity. One motor is controlled by a power relay, whose coil input is controlled by a solid state relay, which is controlled by the current sensor relay.