[TheForge] O.T-. compressor wiring question

[Bob Smolen]

I bought an older Ingersoll compressor from an estate. I did not see it in
operation but it looked to be in pretty good shape.. I believe a model 30T.
It has a 3 phase 7.5 h.p. motor.

To test the unit,I hooked my shop 3 phase directly to the 3 wires on the
compressor motor and it started no problem. I now want to hook up properly
and want advice on proper wiring to pressure switch and low oil sensor.
There is a switch and pressure gauge mounted to the tank. There is also a
low oil sensor for the compressor pump which is monted on the pump and the
wired into the switch. There are two sets of wire that were disconnected
when the unit was moved from the last shop.One set is from the motor and has
3 wires.These are the wires to run the motor which I have verified will
start the motor when hooked up to shop power. There is also a set of 2 wires
extending out of the switch (which I will decribe as enter/exit because I
guess they can lead current into or out of the switch).I do not see where
any other wires could previouly could have come out of or  entered the
switch box.

The switch has 4 contacts(I believe) marked line, load,load, line.The oil
sensor has 2 wires  entering the switch box. One oil sensor wire is simply
connected to one of the 2 wires that exit/enter the switch. The other oil
sensor wire is hooked to a "line" terminal.The second wire that
enters/exits the switch is hooked to the load terminal of the switch.

My uneducated guess is that one of the 3 current source lines  should be
connected to one of the wires extending from the switch. The other switch
wire is then connected to one of the wires extending from the motor. In
other words, current goes into the switch and leaves the switch and enters
one of the lines connected to the motor. The two remaining wires coming from
source are connected to the 2 remaining motor wires. If the oil is low or
the pressure sensor signals the switch to cut the motor, the one leg of the
3 phase hooked to the switch will  open, shutting down the cuurent in that
leg and therby shutting down the motor. Does this make sense? If not, any
suggestions?
 Thanks,
Bob































































































































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