Reassembling motor for air compresser

[harvey4804]

Ok, I bought an older Sears Craftsman air compressor used for $50. 4hp, 220v, 20gal, 10.3/40psi 8.5/90psi. It needed some TLC so I gave her what she needed, basically new paint and clean the saw dust out of the motor. After the disassembly of the motor I went and put it back together and turned her on and my compressor turned into a welder! I took it back apart and found that a contact was touching the motor case which caused it to short out... how is this supposed to go back together?
here's some pix:

here's the guts, see the black plastic top hat looking thing? which way is that supposed to go? This way (1) or...

This way? (2)

If I have it as shown in #1 thats when I hit the case with the contact (see lower pic) but if I have it as shown in #2 the rim sits on the springs

 

[scopx]

I will be watching this thread very closely as have compressor motor problem also. I made air compressor unit basically from scratch using 100 gal propane tank, a single stage devillbiss comp and 5 HP motor.
Problem started when I left for about a month, forgetting compressor was left on.Duh. Noticed it humming when I first came back into garage. Belt had loosened up and had pulley burn mark on belt. Shut it off, pulled and checked both capicators which show to be good. Too cold now to deal with it as mounted outside. Hope that someone versed in 220 motors will provide answers to original poster here and may be able to glean insite.
Thanks

 

[harvey4804]

Well, Im an idiot... this is what its supposed to look like:

I'd finish tonight but the wife is sleepin and she'd be pissed if I fired up the compressor in the living room at midnight! ...wish I had a garage!

Hey scopx, see if there is anything in your motor. mine had about a pound of sawdust in it. vacuumed it all out and cleaned all of the contacts and the humm went away (was replaced with a welding arc but it spun the motor for a second!) Mine should be good now, Ill test it after work tomorrow.

 

[scopx]

If I am not mistaken, the spring loaded switch mech you are installing is the device that switches motor from the start capacitor to the run capacitor.
Hey, some electrician help us out here.

 

[harvey4804]

Yes you are correct. ...hey wait I am an eletrician... but on Helicopters:

 

[hidollartoys]

It should be installed exactly as removed. This will insure proper operation barring any defective or damaged pieces.

 

[Zrexxer]

It should be installed exactly as removed.

DOH! I'm sure he never thought of THAT.

 

[nehog]

Well, Im an idiot... this is what its supposed to look like:

Well, I could be wrong, but I don't think so... In your original post, way #2 is what you probably want.

As the motor spins up, the weights move out, allowing the plastic disk thingie to move in towards the center of the motor. This opens the switch contacts, taking the start windings out of the circuit.

I suspect your first reassembly you had the disk upside down, forcing the contacts into the housing.

Q: did you need clean underwear after your first power-up?

 

[kbs2244]

This is a good reason to use your camera when you are working on something you are not familiar with.

Take some PICs as you go along so you have something to refer to when you are putting it back together.

You are making your own assembly manual.

 

[harvey4804]

Well, I could be wrong, but I don't think so... In your original post, way #2 is what you probably want.

As the motor spins up, the weights move out, allowing the plastic disk thingie to move in towards the center of the motor. This opens the switch contacts, taking the start windings out of the circuit.

I suspect your first reassembly you had the disk upside down, forcing the contacts into the housing.

Q: did you need clean underwear after your first power-up?

Im about to do the final assembly in a minute. Ill let you know how it goes. And no, I'm used to arcing and sparking, I work with wires for a (crappy) living.

This is a good reason to use your camera when you are working on something you are not familiar with.

Take some PICs as you go along so you have something to refer to when you are putting it back together.

You are making your own assembly manual.

I cant tell you how many times I've wanted to take pictures after I was already ballz deep in a project... maybe next time...

 

[scopx]

Yes you are correct. ...hey wait I am an eletrician... but on Helicopters:

My son used to crew on one, and if recall correctly, was called a "sky stallion?" He lamented how pilots enjoyed causing crew to cringe when they would rotate in tight figure 8's (with prop ends close to vertical) while side door(s)? open. He said the "auto-rotate" was adrenaline rush also.

 

[porschedude996TT]

Corretion, lower Helo is a picture is Marine One when the President is onboard, otherwise it is a Nighthawk. The upper one is the same Marine One unless the Prez is not onboard and it is a Sea King.

 

[harvey4804]

Hey! it worked... after another REassembly I had a stray wire that wanted to short out on the case but after I fixed that the motor works great now! ...kinda, I dont know if its the motor or pump but the tank will only get up to ~20-25psi then the motor and compressor drastically begins to slow down almost to the point of stopping. I hit the switch before it completely stops. Any input?

 

[harvey4804]

Corretion, lower Helo is a picture is Marine One when the President is onboard, otherwise it is a Nighthawk. The upper one is the same Marine One unless the Prez is not onboard and it is a Sea King.

yep. someone was watching National Geographic.

 

[nehog]

Hey! it worked... after another REassembly I had a stray wire that wanted to short out on the case but after I fixed that the motor works great now! ...kinda, I dont know if its the motor or pump but the tank will only get up to ~20-25psi then the motor and compressor drastically begins to slow down almost to the point of stopping. I hit the switch before it completely stops. Any input?

Absolutely input: I suspect the start winding is not being opened because the centrifugal switch is jammed. Just a wag, based on a couple of years (30 or so) experience. Did you notice abnormal humming or noise in the motor? Did the motor get hot? Be careful: if the starter circuit is energized too long, you risk catastrophic failure of the starting capacitor!

You should be able to hear the centrifugal switch open (it will make a distinct click sound) if it is working correctly, and if you can see the contacts you will see them open as well.

Disassemble, and remove that plastic disk. Then play with the centrifugal switch and see how it works: weights that move out as RPMs increase causing the disk to move away from the end of the motor.

 

[harvey4804]

I did play with the switch assy and I cleaned and lubricated all of the moving parts. but I dont remember if I can hear the click or not, I'll have to plug it back in and see.

 

[nehog]

Run the motor without the compressor so you can easily hear the motor without the (really noisy, if like mine) compressor running. The click is easy to hear. "Ker-snick" is an example of the sound. The centrifugal switch assembly is an 'over the top' type, something like a compound bow. (hard to get past the center position, but then easy to finish the operation...)

 

[harvey4804]

I dunno how long it takes for it to click but it sounded like it got to full speed and I didn't hear any click after about 10 seconds

 

[nehog]

I strongly suspect then the contacts are not opening the way they should. Your first two photos in the thread show the switch mechanics as they should look while the motor is at rest (not spinning). Manually moving the weights out shows how those fingers move to allow the switch to open.

The photo here:
http://i99.photobucket.com/albums/l284/RyanDHarvey/P1020629.jpg
Is not right, see how the weights are being forced 'out'? Again, I think you need to re-orient the disk the other way from shown in this image. The sleeve part of the disk should face outward. Sit and stare at it for a while, and visualize how it is working, and I'm sure you'll realize where the problems are.

 

[harvey4804]

Ok, 10th time's a charm right? Ok here's how im pretty darn sure its supposed to go, I can definitely hear the click now and the motor actually sounds different. BUT.... it still slows to a stop. possibly the Run Cap., tank valve (which seems fine)?

 

[nehog]

OK, that looks more right... And you can hear the click, so it probably is working OK.

Does it really have a run capacitor? If so, yes, that could be the problem.

If the motor were to run without a load for a while (say 10 minutes) would it get warm? (or hot?) That might be a clue, without a load it should be ice cold.

Also, when is slows down, have you unplugged the motor, and tried to spin the compressor by hand? I suppose there is a remote possibility the compressor is binding up when it gets hot...

 

[Adrian1281]

Yes you are correct. ...hey wait I am an eletrician... but on Helicopters:

<--- Was an Avionics Technician at HMX-1 between 2001-2005. Worked on the "Green" and "White" sides. What a small world...

 

[Adrian1281]

My son used to crew on one, and if recall correctly, was called a "sky stallion?" He lamented how pilots enjoyed causing crew to cringe when they would rotate in tight figure 8's (with prop ends close to vertical) while side door(s)? open. He said the "auto-rotate" was adrenaline rush also.

Anybody who has worked on CH-53E's will tell you their real nickname is "*******", because of the black exhaust from the engines. But Sikorksy calls them "Super Stallions".

Your son was probably talking about what the pilots do to the OCS (Marine Officers School) students when they are aboard for training. Many a time we had to wash the cabin out with hoses due to the amount of vomit on the floor. It is pretty amazing to see how such a big helicopter can be so maneuvarable and fast.

 

[Adrian1281]

Corretion, lower Helo is a picture is Marine One when the President is onboard, otherwise it is a Nighthawk. The upper one is the same Marine One unless the Prez is not onboard and it is a Sea King.

Half of this is incorrect. The VH-60N's are nicknamed "Whitehawks". The squadron's nickname for its aircraft in general is "Nighthawk".

http://en.wikipedia.org/wiki/HMX-1

 

[harvey4804]

OK, that looks more right... And you can hear the click, so it probably is working OK.

Does it really have a run capacitor? If so, yes, that could be the problem.

If the motor were to run without a load for a while (say 10 minutes) would it get warm? (or hot?) That might be a clue, without a load it should be ice cold.

Also, when is slows down, have you unplugged the motor, and tried to spin the compressor by hand? I suppose there is a remote possibility the compressor is binding up when it gets hot...

Yes, it has a run cap.
no, it never really got hot.
I can easily spin the motor and pump together and separately by hand and it spins normally

<--- Was an Avionics Technician at HMX-1 between 2001-2005. Worked on the "Green" and "White" sides. What a small world...

It is a small world, I got there Mar '06. Your patch is probably still on the greenside. Who do you remember?

Half of this is incorrect. The VH-60N's are nicknamed "Whitehawks". The squadron's nickname for its aircraft in general is "Nighthawk".

http://en.wikipedia.org/wiki/HMX-1

Hmmm... I guess not any more. I've never herd it referred to as that.

 

[harvey4804]

I have a run cap on order and should be here within a few days, HOPEFULLY friday! this quick project of giving this compressor a facelift has turned into a nightmare. But hey, it was only 50 bucks!

 

[Adrian1281]

It is a small world, I got there Mar '06. Your patch is probably still on the greenside. Who do you remember?

I was a Huey/Cobra guy when I got there. Worked on CH-53E's from Dec. 2001 until around January 2003 when I got my clearance.

Are you a 46 or 53 guy? I couldn't tell you names, especially on the green side because as I was leaving I didn't know anyone there, all new faces. This was also the case on the white side, people were coming over that I had never seen before.

 

[harvey4804]

Ok, I go the new RUN cap in today. I installed it then pluged her in and nothing has changed. nada dang thing! I think have just about have given up.

 

[harvey4804]

I was a Huey/Cobra guy when I got there. Worked on CH-53E's from Dec. 2001 until around January 2003 when I got my clearance.

Are you a 46 or 53 guy? I couldn't tell you names, especially on the green side because as I was leaving I didn't know anyone there, all new faces. This was also the case on the white side, people were coming over that I had never seen before.

I'm a Phrog guy. would you remember any names from the white side? possibly a Gunny Habreck, Sgt Huerta, Sgt Torres...?

 

[harvey4804]

Anyway, any other input? I can get a replacement motor for $190 at Tractor Supply. Or I could try to sell it on Craigslist and ask $120-150.