Wiring a 240v compressor motor

[dogfacedoc]

Electrical is not my thing

So, I come to you guys. I acquired an old air compressor(pics here) and am finally getting around to setting it up. I have no idea if the motor works or not. Part number search shows it is a Century, 3450 RPM, with an "SPL" hp rating. 240v, 15 amp, output kw 2.98(~4 hp?)

I do not have 240 in the garage, but will have a friend come over and wire that in.

It does not have wiring, so I am asking for help on how to wire up the motor to see if it is good to go. Here are pics of the back. The nuts on the cover are rusted or else I would remove it to try and get better pics.

 

[930dreamer]

Is there a wiring diagram behind the cover?

 

[wyliesdiesels]

Does the motor still have its nameplate attached?

 

[Dagny]

If thats the winding I see in the left side vent holes it does not look good.

 

[dogfacedoc]

No cover, sorry.

Dagny, here's a better pic of the guts

 

[MTW]

For testing the motor only, connect 230V to the 2 studded terminals and try firing it up without the pump load connected. That motor appears to be 208-230V 1Φ only, thermally protected, and non reversible from the looks of the connection plate. A shot of the nameplate would be beneficial...instead of assuming.

To wire it up you need a pressure switch, maybe a contactor with a 230V coil. Find out if the motor is any good first, then if the pump still works.

Most pressure switches are good to 2-3HP rating for controlling the motor directly. You claim it's closer to 4HP (SPL) if that were true a motor rated contactor would be best for longevity. My guess is that motor is more like 2-3HP running and ~4HP during starting, hence (SPL) special rating.

Test it first with temporary connections to see if it runs, before spending time and money wiring it up properly and running 230V to your garage.

MTW Ω

 

[dogfacedoc]

Thanks, MTW. Here is the info sticker.

Back plate off

 

[Jlarson]

That thing is pretty crusty. If you are real attached to it be ready for some quality brain cell killing time with a couple can's of CRC Lectra Clean and probably new bearings. Assuming it doesn't have shorted/open windings or a ground fault. Pull the caps and check them too.

 

[dogfacedoc]

I'm not terribly attached to it, but was hoping I could save a buck or a hundred it it were in decent shape. The more I look at it the more I think a trip to Steve's Wholesale or Harbor Freight is in order.

 

[930dreamer]

The cover that goes over the connectors usually has the wiring diagram on it.

 

[Dagny]

I wouldn't spend to much time or money on it. That winding on the bottom got very hot at some point.