My compressor died today

[alloy]

I've got a 22.5 cfm 7.5hp 220v single phase two stage compressor. Ran it yesterday for 6-8 hours and zero problems. Today it won't start.

I'm not too good with electrical. I can run wires, add a circuit, install a phase converter (with help) check voltages.

It has a mag starter on it. I've checked incoming voltage all the way from the breaker to the compressor. Seems fine. The pressure switch is closed, power to and out of it.

The mag started doesn't engage. I can manually push it in and get voltage to both legs of the motor but no go. Even tried putting voltage directly to the motor bypassing the mag stared and still nothing.

Thankfully I have a backup compressor, but it's half the cfm and my pressure blast cabinet keeps it running constantly.

I've found a replacement motor for $535 with free shipping which isn't bad, but before I buy it I want to make sure I'm not missing something.

HELP!!!

 

[Reddinr]

Does it have a starting capacitor? That could be blown. <$20 maybe.

 

[markba633csi]

I would check the connections right at the motor terminal board and look for burned or melted lugs or wires
It's possible a connection inside the motor let go but do some easy checks first. Check connections to capacitors too.
If there is no hum at all then it's probably a broken connection not a bad capacitor
-Mark
The centrifugal switch in the motor may be shot but you might be able to replace it for much less than a new motor

 

[alloy]

It has three capacitors.

Connections look good. Nothing loose, nothing burned.

No hum, nothing at all.

Actually after blowing up the pic I see corrosioo a couple of the spade connectors on the the capacitors. I'm going to clean them and see if that helps.

 

[Gaffer]

I have a Campbell Hausfeld with the same specs as yours. On my motor are two semi-circular plates attached by screws. They house the start and run capacitors. If you have a meter it would be a pretty simple troubleshoot to ensure you have proper voltages, and specifically where you are losing the connection.

 

[JimDawson]

Press the little red button just below the starter contactor, the one on the overload

 

[Gaffer]

I believe those are your run caps. Do you have another cover, possibly on the side of the motor? That would be your start cap. Caps can be tricky by looking fine but they're not. Your better meters will read capacitance.

 

[Gaffer]

Good eye Jim. It does appear to have tripped.

 

[Reddinr]

It looks like the two caps on the right are motor start caps and appear to be wired in parallel which doubles the capacitance. Probably needed for the larger size of the motor. The metal can one is likely the motor run cap. Much more likely that one or both the motor start caps is gone. They can be tricky to measure even with the right meter. It is a cheap trial and error fix to just replace both of the motor start capacitors (if your reset button push didn't fix it).

 

[alloy]

One of the first things I tried was the reset.

Just pulled the wires on the caps and reseated them, nothing.

If I push the mag starter there is voltage going to the caps.

I guess I don't understand why the mag switch isn't engaging.