Source for vintage Square D pressure switch nuts/bolts
- Thread starter mawrick
- Start date
I would think for the ground any common screw could be used. and for the nut, won't a regular nut work? or someone with a lathe ,knowing the thread size could make you a nut
Will probably work, was just wondering if this was a certain type of nut (with a name)
so I could try to source em, but guess it's nothing common these days 454ragtop
Well-known member
I guess I'd call that a slotted barrel nut, pretty unlikely you'll find one anywhere but in another switch. Is this compressor 3 phase or single phase? If single phase, you only need 2 pair of terminals, don't switch the ground. If there is continuity between the motor and all the rest of the metal parts of the compressor, no need to ground the switch long as the motor is grounded. The nut that's a little chewed up can probably be fixed with a hacksaw, either touch up that slot, or flip it over and cut a slot on the other end.
This is a 3 phase motor, and the motor sits on the tank (same stand as the switch).
I haven't checked to much yet how it's best to wire it up, as the motor is drawing 28.5Amps (I think 7.5 Hp), I think it have been wired directly thru the switch, but was thinking of hooking up the motor to a contactor/protector and just use the switch to control the contactor - but if it's fine to pass it straight thru the switch then I'd rather do that.....
Provincial
Well-known member
You will find that you will be replacing the pressure switch more often that desired if you wire the motor through the pressure switch. This is a major reason why contactors are standard for motor installations above a couple of horsepower. You will be way ahead to use the pressure switch to control a contactor, since the current through the contacts of the pressure switch will be a tiny fraction of what is going to the motor. Also, you will only be using one set of points in the pressure switch, so if you wear them out, you can just move to another set.