holding circuit

Thread Starter


Joined Feb 13, 2009
im still not sure how to wire a holding circuit. i know to bring the 120v into the stop btn and back out into my start btn from there i go up to my contactor, from the contacts cr1-1 do i bring both wires back into the n/o switch.on our trainer the start btn has 2 n/o contacts one is energized and the other side is the side i want to parallel in to create my holding . also is there a web site i can go to that will break the wiring down an explain all of the processes of wiring?
Last edited:


Joined Jan 3, 2009
I'm designing a circuit in my head for a pump start on a irrigation system. The pump will have a low flow switch on the discharge side, that will open and stop the pump if it should run dry. I may put a pressure switch in as well. The problem is that the pump must start and run long enough for the water flow to close the low flow switch to create the holding circuit.

I was thinking of using a timer relay that I can energize for the set amount of time needed to bring the pump up to capacity. The NO contacts of the timer relay would be paralleled to the low flow switch. Then when timer relay times out the flow switch should complete the circuit and keep the pump running until the irrigation controller turns off the pump run signal, or the flow switch opens.

The biggest problem I have is that the irrigation controller puts out a 24 VAC signal, the timer relay, and motor start relay that I have use a coil voltages of 120VAC. I do have a 24 V coil cube relay that I can use one set of NO contacts to energize the timer, and the other set of NO contacts to complete the circuit through the flow switch and and starter relay with 120 V. I will also add a bypass switch, so that I can run the pump without the flow switch timer relay and so on, for trouble shooting, should a problem ever arise.

What I was wondering if anyone has designed a circuit like this or might have any suggestions or a maybe even a schematic?