Of Compressors, Breakers and Amps

[SwedeChariot]

Hi folks,

This is my first time posting on this forum.

I recently bought a used DeWalt/Emglo D55170 8 gallon pontoon-style air compressor. It's a belt driven, 1.5 hp, 7.5 amp unit. I believe it's dual voltage but it came to me set up for 115 volts. I don't have a 220 outlet in my garage.

My problem is that about half the time I fire it up it trips the breaker. It runs for 3 or 4 seconds, then dies. The breaker is 15 amps. The house is 10 years old.

Any theories about what's going on here and how to correct it? I'm not especially knowledgeable about household electrics, so I don't know if swapping out the breaker for one of higher amperage is advisable or whether I'm liable to burn down the garage and/or house.

Since this is a roofer compressor, I assume it's rated for a standard household amperage. I guess that means that either my electrical setup is substandard, or else I have a maintenance issue with the compressor.

Thoughts?

 

[Jbullfrog]

Did you plug it in before you bought it? It maybe rated at 7.5amps running but probably pulls 2x that when it starts. The outlet you are using may have other loads on it and not have enough left to start the motor.

 

[ddawg16]

What else do you have on that circuit?

 

[pattenp]

Are you plugging it directly into an outlet or using an extension cord?

 

[Alchymist]

Temporarily move it to a 20 amp circuit and see if it trips.....

 

[SwedeChariot]

Thanks guys.

There are lights on the circuit but I had the lights off during some instances of the breaker failure. Also, I have succeeded in running the compressor with the lights on, although they dim and flicker.

The unit was plugged into an extension cord. I moved it and plugged it straight into the wall, at which point it worked. I guess I'll try it a few more times and see if it continues to work without tripping the breaker.

I don't have any 20 amp circuits in the house, just 15, 40 and 60.

 

[pattenp]

If using too long and too small gauge extension cord can cause a voltage drop causing the amps to increase, tripping the breaker.

 

[Norcal]

A 1 1/2 HP motor should draw around 15 amperes at 115V are you sure the nameplate data was posted correctly? Some Emglo compressors had a switch to change over from 115V to 230V so they could be run at either 120V or 240V, if that was the case w/ a compressor being a hard starting load, it would be EZ to trip a breaker if the switch was in the incorrect position.

 

[SwedeChariot]

Norcal you're right: they market the compressor at "7.5 amps" but the nameplate says "FLA: 15.2/7.6." So I guess my breaker is borderline. Would it be unwise to replace my 15 amp breaker with a 20 amp breaker?

The extension cord I was using was pretty long and of finer gauge than the compressor cord. Now that I'm plugged into the wall, maybe be okay if i keep the lights off at start up.

 

[pattenp]

Absolutely do not replace the 15A breaker with a 20A breaker.

 

[SwedeChariot]

Thanks pattenp, can't put it more plainly than that.