Air Compressor - Breaker Tripping off

[rshiggaon]

I found the manual online and it says on page 14, “This unit must be connected to a 230V circuit with a minimum rating of 40 amps. Do not use this unit on a 208V circuit of any kind.” Look at the label plate on the side of the motor and see if it can be wired to run on 208 volts. You may have to replace the circuit breaker again and go up to a 50 amp and make sure you have 6AWG wire feeding the air compressor. Check to see how many amps the air compressor is drawing when it starts. Here’s a link to the manual if you don’t have it. https://www.northerntool.com/images/downloads/manuals/459242.pdf
How big was the first circuit breaker that you replaced? What size wire do you currently have feeding the air compressor?

It was 30 AMP and probably a 12 gauge wire. We could see some burns on the wire. We now replaced it with an 8 gauge and 40 AMP breaker. I guess when this goes bad we will make sure we buy the new one that is compatible with 208 V.

I have learned quite a bit with this breakage and thank you for the guidance. Hoping it does not act stupid again.

 

[Zal]

It seems only major brand motors like dayton- leeson etc will rate both 230 and 208. They are supposed to work if voltage is within 10%. Not in china voltage?

 

[2Biz]

Lots of good advice here, especially putting an AMP Clamp on the wires to see how many amps each leg is pulling. The first step to rule out a motor issue is to see how many amps its pulling.. The wire size and breaker size is a given...It states what is required right on the motor.

 

[mjwalsh]

rshiggaon,

If were my problem.
I would watch the pertinent air gauge to see exactly when the air compressor is shutting off at ... with its automatic on-off pressure switch. If that switch is intermittently failing ... allowing the pressure to get too high ... you may see simultaneously with 2Biz's clamp on ammeter ... the "amp draw" creep up enough to make too many amps resulting in the blown breaker.

 

[MEP001]

If that switch is intermittently failing ... allowing the pressure to get too high ... you may see simultaneously with 2Biz's clamp on ammeter ... the "amp draw" creep up enough to make too many amps resulting in the blown breaker.

You probably won't ever see that because the compressor will most likely keep running and one of the two pressure pop-off valves will go before the breaker trips.

 

[MEP001]

It is a North Star Air Compressor, attached are the specs of the compressor. The breaker is 40 AMP. The seller that we brought this car wash installed it in 2021. My tech guy mentioned that it cannot be the compressor but the wire that is connected to the breaker, is not thick enough to hold this electricity.

So I stopped at a Northern Tool today and looked at this exact compressor. The motor is rated 208-230V. The ONLY REASON to not run it at 208V is because it will use 50 amps which is above the rating of the thermal overload. If you haven't done it yet, you might want to check your voltage. The overload should be replaced with a 50A module if your incoming is 208V.

 

[Laser Schofield]

that's the compressor tag photo, there's a tag on your motor, that'll have FLA and SF.
208 and 230 wire the same, those cheaper motors already run into the service factor, usually lowering the load/unload helps keeps unit under FLA when everything new,
but a real 7.5hp 1/230motor suppose to have a 80amp breaker and 8 ga wire, at 208v + 10%
to checks, belts squeaking? loose belt slip, short stroke cycle,
other thing is the in-tank check valve will leak back, leaving pressure on the heads at start up, lot of people don't even know ones in there,
pressure switch and unloading switch is the simplest and most common issue, and the cheapest,

 

[MEP001]

those cheaper motors already run into the service factor

This unit has a Baldor motor, not the best but better than the Chinese POS most of them have.

 

[Waxman]

The air compressor is such a vital part of the car wash that I'm not sure why anyone would want to buy a cheap one in the first place. The champion centurion two that I bought 18 years ago has worked perfectly for almost 2 decades. I would say that the price was justified!