Working with a new to me air compressor

[KenMathisHD]

Hi guys! I've never considered mucking about with my tools as much as what I drive, so I'm jumping into something I don't know a whole bunch about.
Recently I was donated a 60 Gallon Vertical Craftsman Air Compressor, it's a twin cylinder oilless 6.5 marketed horsepower compressor my grandfather bought sometime in the 90's. He replaced the pump twice, but after the third connecting rod for one of the pistons broke he put the thing into storage.

I'm not certain how long it was not in-use for, though I'm certain it's been stored for at least 10 years, during which time it has never been touched. Fast forward to today, and I'm pulling apart the pump and motor to see if I can figure out anything about how this thing works and see if I can pull out the motor to clean things up and maybe salvage it. The pump, with a new piston and fresh grease in the bearings looks like it could run again. Though when I tried pulling the pump off the motor, it pulled the darn thing straight out. The coils are still in the casing, though the stickier parts of mud dauber nests remain on the coils and I can't figure out how to pull the coils out to clean them off.

The motor is by A.O Smith, its model number is MO-3024. Is it possible to pull the coils in order to clean them? The motor worked fine when the thing was stored, but I didn't want to plug it in and test it right away for fear of setting the countless nests inside on fire. If it doesn't work then it's not a loss as I'm thinking about converting the compressor to a belt-driven setup, but if I can salvage the motor by cleaning the coils and somehow removing it from the pump, depending on what the end of the output shaft looks like I'd like to see if I can mount a pulley on it instead of dropping money on a new motor.

 

[NC Rick]

I have a quite old craftsman 80 gallon all US made ac that was given to be “wore out” 25 years ago. The 5hp Motor had bad bearings and the motor mounts broke off with chunks of the case. I removed the stator winding, welded and painted the housing and installed new bearings. The compressor runs like new to this day.

 

[KenMathisHD]

Is the stator winding the thick copper coil that sits in the motor housing?

 

[NC Rick]

Is the stator winding the thick copper coil that sits in the motor housing?

Yea and sits in a steel laminated cage that is slid into the housing. All motors are not assembled in the same way so proceed with caution. The connection wires are usually tight and snaked around. It would be a must to have a reasonable mechanical and electrical understanding of what’s going on. Mine has end caps with the bearings and stuff. The motor control and protection heater is in an external enclosure.

 

[KenMathisHD]

After reading this I got the idea to look at the opposite end of the motor for answers - was able to take everything off of both ends and expose the stator winding on both sides, but the coils of copper on both ends of the cage seem to stick out too much to allow the stator to pull out and tugging them with pliers seemed like a bad idea. I can’t figure out how to remove the thicker exposed coils at both ends without damaging anything - is that even possible or would that likely destroy the stator?


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[NC Rick]

It would be very easy to destroy the stator. I can’t see what’s happening so I can’t really tell you how to do it. I would like to be helpful but if the motor is working, I wouldn’t mess with it. If it were scrap in either case, I’d have at it.

The laminations are retained in the case by some means. I think mine was actually held by the end caps and some rust. I did mine closer to 30 years ago so I don’t remember everything whit the wire is coated with an insulating material and uses nomex or some type of high temperature paper to fit the coils of it into a spline-like shape in the laminated body. I was able to push on the laminations and extract them as a unit from the steel housing. This may or very well may not be possible on your motor.

 

[NC Rick]

It’s still working.

 

[MacMcMacmac]

This compressor is not worth the time and money to resurrect. It will annoy the hell out of you with the racket before it once again throws a rod.

 

[KenMathisHD]

This compressor is not worth the time and money to resurrect. It will annoy the hell out of you with the racket before it once again throws a rod.

I was going to see if I could mount a pulley to the shaft of the motor and use a different pump but as of yet I haven’t been able to get the shaft disconnected from the pump - if I can’t do that then the motor is lost and I start looking around for pieces for building a belt driven system.

 

[KenMathisHD]

This is what I was talking about with part of the motor still being attached to the pump, it was pulled out when I pulled the pump frame out, there’s a weight on the front that I can’t seem to pull off and I reckon it’s hiding whatever is holding the thing on there. Any ideas?

 

[KenMathisHD]

It’s still working.

Pic of the stator in it’s current predicament from both sides

 

[KenMathisHD]

NC Rick, in your motor, where were the laminations located if you don’t mind my asking? I know they won’t be in the same place in different motors, but I figure if I understand where they’re most likely to be located I could probably poke round and look in a similar area in this motor


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[driftpin]

I expect that in TX you should be able to find a good quality used compressor that will be much-quieter than that oil-less one.

Here's one from by the airport, dunno if it's still available, it should be able to do whatever you want/need:
https://sanantonio.craigslist.org/tls/d/san-antonio-air-compressor/6795215551.html

$1K, 10 HP motor, big tank.

Save the tank from yours if you need the extra air capacity.

 

[NC Rick]

NC Rick, in your motor, where were the laminations located if you don’t mind my asking? I know they won’t be in the same place in different motors, but I figure if I understand where they’re most likely to be located I could probably poke round and look in a similar area in this motor


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Was that motor running? It looks like half of the stator is burned up (I’m judging that by the color difference of the varnish on the windings).

I’ll agree that the compressor isn’t other the effort to fix but you can play with it and learn. I lost track here, sorry: what do you hope to accomplish by removing the stator? You can see that my compressor has a much different kind of motor. You do have the end covers and bearings out. Remind me why you are wanting to remove the stator from the simple housing? There may be crimps in the housing to lock it in place as it has to be able to resist rotational forces in opposition to the output power.

 

[KenMathisHD]

The motor was working when it was stored, though I haven’t been able to test it yet - during it’s storage it became the home of multiple mud dauber nests and I didn’t want to risk the nests catching fire if I tested it. I’m trying to pull the stator out to see if I’ve gotten all the abandoned nests or if I’ve missed any, though if I can’t separate the rest of the motor from the pump then it’s lost anyways which isn’t that big a deal.


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[engineer2]

We have a two cylinder Craftsman pump on the junk pile at work. No motor though. It kept shedding the fan and then the motor burned out. Not sure what would interchange. They are pretty common on craigslist.

The Craftsman oil-free are good compressors for home use if you don't mind the noise. I had one for 25 years until the motor went bad.

 

[NC Rick]

I strongly suggest no further disassembly of the stator. Use compressed air to clean it out, check the bearings and thrust components and put it back together. The only reason I had to take mine out was to weld on the case. The o.d. Of the laminations will likely be round and in full contact with the case. The temperature of the laminations should not become hotter than the outer casing will and if that are leftover bugs in there, let them fry. It looks clean to me.

I was able to push apart the stator and the case and as seen in my photo, the welded to the case “feet” are what mounts the motor to the plate above the tank. Yours looks like a flange mount motor.

 

[NC Rick]

Also, FYI, the flyweights on the armature control the starting contacts, likely connecting a capacitor into the circuit until decent rotation is achieved. When that part of a split phase motor are bad, it is possible to get the motor to run by spinning it by hand. (Be aware of risk as it’s nice having all our fingers).

 

[KenMathisHD]

Is the armature the thing is still can’t get disconnected from the pump in the last picture on page 1 here, which would make the black circle piece on the end opposite of the pump the flyweights?


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