gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
210726-2401 EDT
paulengr has nicely described the problem, and provided a solution.
I want to continue from there. I believe that it is possible to use only one timer relay.
First, both pressure and well pumps are fairly high power, and therefore their relays ( contractors ) will be slower to actuate ( close a normally open contact ), than a small timer relay.
So I should be able to use a single timer relay.
My circuit would be ----
For the WELL pump motor I have a normally open FLOAT switch that closes when water level is LOW. This contact is paralleled with a normally open contact from the WELL pump contactor ( call this a holding contact ). In series with this set of parallel contacts is a normally closed contact from a high level float. This parallel, series combination goes to the paralleled coils of the WELL PUMP contractor, and TIMER relay.
When low water level occurs the WELL PUMP and TIMER coils are energized, and the HOLDING contact closes and keeps the WELL PUMP running until the HIGH level float switch opens.
The circuit for the PRESSURE pump is very similar. But here we have a LOW PRESSURE normally open contact that closes on low pressure. In series with this LOW PRESSURE contact is a normally closed contact from the TIMER relay in the other circuit. Connected across these two contacts is a normally open contact from the PRESSURE pump contractor. In other words the pressure holding contact. In series with this combination is a normally closed HIGH PRESSURE contact.
Because the timer relay is faster operating than either of the other two pump contactors only one pump contactor will close when both are requested at the same time. Were the two big contactors to actually be fast enough only the well pump would stay on, and the other would only half start.
The software for this site is very poor. It constantly changes my contactor spelling to contractor.
.
paulengr has nicely described the problem, and provided a solution.
I want to continue from there. I believe that it is possible to use only one timer relay.
First, both pressure and well pumps are fairly high power, and therefore their relays ( contractors ) will be slower to actuate ( close a normally open contact ), than a small timer relay.
So I should be able to use a single timer relay.
My circuit would be ----
For the WELL pump motor I have a normally open FLOAT switch that closes when water level is LOW. This contact is paralleled with a normally open contact from the WELL pump contactor ( call this a holding contact ). In series with this set of parallel contacts is a normally closed contact from a high level float. This parallel, series combination goes to the paralleled coils of the WELL PUMP contractor, and TIMER relay.
When low water level occurs the WELL PUMP and TIMER coils are energized, and the HOLDING contact closes and keeps the WELL PUMP running until the HIGH level float switch opens.
The circuit for the PRESSURE pump is very similar. But here we have a LOW PRESSURE normally open contact that closes on low pressure. In series with this LOW PRESSURE contact is a normally closed contact from the TIMER relay in the other circuit. Connected across these two contacts is a normally open contact from the PRESSURE pump contractor. In other words the pressure holding contact. In series with this combination is a normally closed HIGH PRESSURE contact.
Because the timer relay is faster operating than either of the other two pump contactors only one pump contactor will close when both are requested at the same time. Were the two big contactors to actually be fast enough only the well pump would stay on, and the other would only half start.
The software for this site is very poor. It constantly changes my contactor spelling to contractor.
.
