Thought I'd throw this out there - maybe one of you know how this should be wired, as I think it may be wrong - or possibly the oil relay isn't working right.
I "inherited" a large Industrial Air brand compressor, which was missing the 5HP motor. Easy enough, I bought a new motor, got it put on along with a regulator, etc. It is a 240v single phase setup.
To start it, I have been pushing on the bar of the magnetic "definite purpose controller". It then pumps great up to 175 PSI and then pressure cut-out opens, the relay field collapses, and the motor is cut off. Perfect.
The problem is that when the cut-out then closes at about 140 PSI, the field is not re-energiezed so that the motor will turn back on. This is because the cut-out's supply is AFTER the DPC, so I don't see how that could ever work. However, if you supply 120V to the cut-out side - still nothing happens because the other side of the coil (one of the two other red wires - not sure which one does what) is floating (not ground).
I think the problem is probably the oil relay. Not exactly sure what is normal with that, as I cannot find any schematic on it - or the DPC either with the three contacts in the top beside main power. This is really my issue - not knowing what should be what so I can set it straight.
Here is the DPC:
Here is how the cut-out is wired - very typical DPST arrangement:
And here is how the box is wired, with the supply at the bottom, an oil relay on the left side, then the DPC at the top:
I "inherited" a large Industrial Air brand compressor, which was missing the 5HP motor. Easy enough, I bought a new motor, got it put on along with a regulator, etc. It is a 240v single phase setup.
To start it, I have been pushing on the bar of the magnetic "definite purpose controller". It then pumps great up to 175 PSI and then pressure cut-out opens, the relay field collapses, and the motor is cut off. Perfect.
The problem is that when the cut-out then closes at about 140 PSI, the field is not re-energiezed so that the motor will turn back on. This is because the cut-out's supply is AFTER the DPC, so I don't see how that could ever work. However, if you supply 120V to the cut-out side - still nothing happens because the other side of the coil (one of the two other red wires - not sure which one does what) is floating (not ground).
I think the problem is probably the oil relay. Not exactly sure what is normal with that, as I cannot find any schematic on it - or the DPC either with the three contacts in the top beside main power. This is really my issue - not knowing what should be what so I can set it straight.
Here is the DPC:
Here is how the cut-out is wired - very typical DPST arrangement:
And here is how the box is wired, with the supply at the bottom, an oil relay on the left side, then the DPC at the top:
