Wiring a Mag Starter for an Air Compressor

i assume this compressor supplies air to a compressed air storage (pressure) tank ??? I assume the compressor needs to stop at a certain top pressure and automatically restart at a certain low pressure ??? Is this so ??? If yes, then the Mag Starter needs to be controlled by a suitable pressure switch, set to the desired high - low limits. The mag starter can be either line voltage or low voltage. This is at your choice. For low voltage operation, the mag starter COIL must be for 24 volts. The 24 volts are supplied by a small transformer with a suitable VA rating. The pressure switch is wired to the starter coil and the starters main contacts (at line voltage) are wired directly to the compressor motor. Such a hook-up is very simple, but must not be described in words, which can be mis-interpreted. You need a schematic circuit drawing.

Look inside the cover of the mag starter. Instructions should be there. You need to match the heaters to your motor, instructions inside the cover. If not, the dealer should have them, you'll need to go back for heaters, anyway. Seven hp seems a lot for single phase, is three phase available?, it's cheaper.