Who knows 220 motors?

[mbryson]

I don’t know much. 220-221, whatever makes sense is my knowledge. I keep popping my breaker on my compressor. I can turn the compressor over by hand fairly easily (maybe that’s bad?) so I don’t think the electric motor is over heating from drag? Anything I can check in the motor? This dawg is something I bought in about ‘97, but it doesn’t have a LOT of hours on it.

 

[Gravy]

If you look at the brushes, you can see if they need replacing. That's where I always start.

 

[boogie_4wheel]

Does it just hum then trip after a short period? Pull that hump cover on the motor and check for a bad starting capacitor.

 

[mbryson]

Does it just hum then trip after a short period? Pull that hump cover on the motor and check for a bad starting capacitor.

It lasts about 10-15 of run time and then trips. I’m using a DA sander which is a total air suck. Not sure what else uses more air

 

[Jedisdead]

I would put a amp clamp on it and see how many amps it is pulling. It could just be the little circuit breaker is getting weak.

 

[frieed]

what the motor specs , what size breaker, is the wiring the correct size for the breaker.
10-15 what? sec, min, years . Does the trip always happen when the motor starts up ?

 

[moab_cj5]

@Paul R knows, but he's off playing...

 

[mbryson]

what the motor specs , what size breaker, is the wiring the correct size for the breaker.
10-15 what? sec, min, years . Does the trip always happen when the motor starts up ?

I love typing on my phone. 15 min. Wiring is correct for the breaker (50 amp----I think it's 10/3 but that's off memory---it's exactly what my electrician told me to get and it wasn't the cheapest thing--every 220 outlet in my garage is on it's own breaker )



I didn’t see a chunk of the main insulation to verify.



Those black/white wires are the 220 leads

 

[Jedisdead]

Is it tripping at breaker panel or at the compressor? I think #6 is needed for 50amp going off memory.

 

[frieed]

I hope it's bigger than 10/3 which is rated 30A continuous.
The wire on the top breaker pair looks bigger, maybe.

I put a 100A sub-panel in my garage which is now full.
The 50A circuit for my welder is on #8 which is ok due to the duty cycle of the welder but for a continuous load it would need to be #6.
When TIG welding aluminum @220A the machine maxes out at about 38A. If I were to grab some big electrodes and really crank up the stick welder to 300A I'm pretty sure I'd trip the breaker. The MIG maxed out to 300A I'm not sure.
My compressor has a dedicated 30A circuit on 10/3 which is overkill for this compressor but maybe a 5hp one will show up some day.
I have another 10/3, 30A circuit for the AC with supplemental heat.

Back to your stuff...
Most decent size air compressors have an unloader valve which vent the compressor output to air to lessen the load until the motor gets up to speed. If yours has one it could be stuck causing greater loads at startup.
Induction motors like this can draw 2x their rated running amps when starting under load, which is why you need a pretty big generator to run the AC in an RV.
It's also not unheard of to have a breaker be too sensitive. If you are comfortable with it, swap those two breakers and see the compressor trips the other one.

 

[mbryson]

Is it tripping at breaker panel or at the compressor? I think #6 is needed for 50amp going off memory.

The little breaker on the motor. The panel breaker is not tripping

 

[frieed]

good catch on which breaker is tripping @Jedisdead
@mbryson , details, details, details.....
would appear the supply circuit is fine.
Still, a breaker tripping means overcurrent or bad breaker.
If overcurrent, why. possibly bad unloader valve, bad motor, or maybe bad start capacitors.
When it starts up does it seem to start kind of slow to start ? bad start cap can cause that.
Back to an earlier question, does it trip on startup or while running.
@STAG suggestion of removing the belt is a good one since that will completely unload the motor.

 

[Corban_White]

The little red button on the motor? That isn't really a breaker, it's a thermal switch (usually bi-metal). Think of it like a resettable turkey timer. They can go bad and are pretty easy to bypass/replace if so. I'd check the amp draw with a clamp meter and compare it to the (very dirty) sticker on the side of the motor. You are looking for the FLA (Full Load Amp) number on the motor. My guess (WAG without knowing more about the compressor model) is that it should be around 20 amps. If it is not drawing significantly more than the motor plate says then I would suspect either the thermal switch is bad or the centrifugal switch (inside the back of the motor, pretty easy to access) is stuck. Take the back cover off and take a look at both. The centrifugal switch disengages the start windings once the motor is up to speed. It has weights and springs that can get gummed up and contacts that can sometimes get stuck. If the start winding isn't disengaging it will get warm pretty quick. Some cleaner and maybe a file is probably all you'll need.

 

[frieed]

If the centrifugal sticks closed, the starter winding will stay energized and the motor will get hot.
switch stuck closed = motor gets quite hot
switch stuck open = slow to no start (motor just hums)

 

[Corban_White]

@mbryson did you get this fixed?

 

[mbryson]

@mbryson did you get this fixed?

I haven't yet but need to address it as I start planning to use the compressor for spraying primer in a week or two. I think the outlined items above are a good start. Cleaning the motor and motor breaker inspection/cleaning seem like a cheap and logical place to start. I might even kick this off tonight ?

(things to do on the car....
1) weld two small patches on the car
2) mask and prime the car
)

It'd be smart/efficient to get the compressor up to snuff before I try to start spraying primer and have "fun" issues while half way through that process