Compressor Tech...

Caver Dave

Caver Dave

Just holdin' it down here in BFV
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Mar 10, 2005
Location
Hooterville (24171)
A bud has a small air compressor with very little run time at this point that started kicking the (house) breaker after 10 seconds.

It's a 115V motor rated 2HP w/ a single capacitor (IIRC, 120mf @ 5%). Upon start up, it runs pretty slowly, then speeds up a bit before kicking the breaker.

Any chance the cap is fried and causing this? I looked at it briefly and didn't see any evidence of arcing, damage, leaking. As my 12th grade electronic theory has been purged over the past several dozen years, any way to test the cap/start-run circuit for issues?

TIA :beer:
 
running on extension cord? what size breaker is it blowing?

Does it do this when the tank is empty or just when it starts developing pressure ?

is there any air leaking out after it shuts off ?

Belt drive or oil-less ?
 
Blkvoodoo said:
running on extension cord? what size breaker is it blowing?
Click to expand...

Both extension cord and direct to the recpt. at the house.

20A breaker (only thing on that circuit and within the 15.5V startup load)

Blkvoodoo said:
Does it do this when the tank is empty or just when it starts developing pressure ?
Click to expand...

Either... with *some* pressure (30-40 PSI) and empty

Blkvoodoo said:
is there any air leaking out after it shuts off ?
Click to expand...

None

Blkvoodoo said:
Belt drive or oil-less ?
Click to expand...

Direct drive oil-filled single cylinder
 
is there oil in the case ? at the proper level ( gotta ask, sorry) is it possible it had been run low on oil, or run at an angle for a period of time resulting in oil starvation ?

These use "splash" oiling, if the pump isn't level while running, oil goes to one side and it can't be splashed. Causes the rod to sieze on the crank. causing high amperage draw.

many of these also DO NOT use automotive oil, it's too heavy, which could also cause a high amperage draw.

you do not state brand or model, pull the crack case cover off, ( drain oil first) and pull the rod off the crank if you are able, run the motor alone, see what happens.

if the crank looks galled, take some fine emory cloth and polish the crank ( remove as much of the rod deposits as possible) and smooth the rod journal as best you can.

depending on brand, you could probably get a replacement rod for about $10-$15.

I used to repair these things, have done this many times. and is always a result of either low oil or unit not sitting level when being used.
 
Before we tear it apart, try a second circuit orr plug in, and make sure you dont just have 1 weak/bad breaker
 
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