I inherited a large 220v Sanborn Compressor. I started it several times and it seemed to work fine so I ran air lines through out my garage and shop. When it was done, I flipped the breaker and ..... nothing. I got a humming sound for a few seconds and then it went silent. I've hit the reset button to no avail. If I turn off the breaker and then on within a few minutes, I don't get the humming sound until it's been off for a while. I'd like to turn the motor over by hand but I can't do that until I've removed the open cage protecting the pulleys and belt. Before I take off the cage, does anyone have any suggestions on what's going on with the unit?
Sanborn Compressor Problem
- Thread starter tsanborn
- Start date
jrsulo
Well-known member
Is tank empty or full ??,,,,if full it might be under a load meaning it has a bad check valve or unloader
jrsulo
Well-known member
Or a bad capacitor
No residual pressure in the tank. A bad capacitor might be at fault. Where would the capacitor be mounted typically. I probably should have attached a photo of the unit. It is an old unit and NOISY when running so I don't reject sabotage by the neighbors (kidding, kind of).
could be a bad start capacitor or bad centrifugal start switch.
the capacitor could be under a domed shaped cup on the motor or under a plastic housing.
the start switch will be under the bell end of the motor .
some pics or a model number would help
the capacitor could be under a domed shaped cup on the motor or under a plastic housing.
the start switch will be under the bell end of the motor .
some pics or a model number would help
35Ford
Well-known member
Single or three phase?
OK, here are some pics of the beast. Not sure if it's single or three phase. I'd love to get the old Sanborn going, not the least because that's my last name. Nope, no relation but I can always lie about it. I'm guessing the capacitor is under the tan and grey plastic box in front. I open it up tomorrow and report back on what I see.
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Cruzan80
Well-known member
Grey box in front is the pressure switch, and possibly disconnect. The capacitors are in the squarish "hump" on top of the motor. Open that, look for markings on the tubes, order and swap them out.
You would know if it was 3ph, as it isn't common in residential households.
Edit: Cobbler posted a better cropped pic of what I was describing
You would know if it was 3ph, as it isn't common in residential households.
Edit: Cobbler posted a better cropped pic of what I was describing
you'll find the capacitor(s) under here
also have you confirmed 240 volts at the motor?
also have you confirmed 240 volts at the motor?
OK, I know that this sounds lame but I don't see how that square box with the reset buttons comes off the body of the motor. There's two screws on the front that I believe just hold the reset button in place. there's a small nut on top but removing it didn't help, seems too small to be the only thing holding the box in place. Any ideas would be appreciated.
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it probably has a foam gasket between it & the motor that needs a bit of persuasion
RTM
Well-known member
Would the capacitor be under the lump lower left here?you'll find the capacitor(s) under here
also have you confirmed 240 volts at the motor?
Cruzan80
Well-known member
Yes, that is my (now updated) guess. Check the lower left (screws should hold that cover on)
Leroy
Member
Would the capacitor be under the lump lower left here?
Yes -Remove the flat head screws, one on each side. Once you remove it, be careful to not touch the terminals on the capacitor. It could give you quite a shock.
Yes -Remove the flat head screws, one on each side. Once you remove it, be careful to not touch the terminals on the capacitor. It could give you quite a shock.
Dagny
Well-known member
There are caps under both covers. I believe one is a run cap.
Success, replaced the two capacitors and didn't even get hit by the discharge from the old ones! My thanks to everyone for your help in diagnosing the problem and suggesting we needed new capacitors. Unfortunately, the beast is a noisy one and it didn't take long for my neighbors to stop by and ask what all the noise is about. The Sanborn compressor was given to me by a friend who never used it and now I think I understand why. Just too noisy for a residential neighborhood. So, if anyone wants it and can pick it up, we're in Santa Barbara CA. But now that I've set up all the lines throughout the shop and garages, I'm thinking of purchasing a somewhat smaller compressor with good noise suppression. The question is how large of a compressor do I need? I work on my old classic cars and those of friends a lot and have a need of most air tools from time to time. But I'd generally be the only person working in the shop. My grinder and bead blaster probably have the highest continuous demand on the compressor. I don't need the compressor to be mobile (I've got that one already) and I have 220v where the compressor would live. I'm guessing I need a 20 to 30 gallons tank. I would appreciate hearing opinions on what size I should be looking at and if you've had any good experiences with one of the low noise compressors in that size range. And please let me know if anyone wants my old one.