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salem747

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Discussion starter · #1 ·
I was "lucky" enough to find an old compressor in my area for $100. It is a 60 Gallon upright that had a seized motor. The motor is HUGE all cast iron and weighs a ton. But the nameplate is gone from the motor and I can't find any info on the compressor itself on the interweb. The wiring is funny too. Somebody had a 2 wire going into the JB on the motor white to green, black to black and the white in the motor jumpered to itself. It looks like it was run in this configuration but I'm not sure how it would have worked! It must be 220V how could it be run on 2 wires?

I took apart the motor and it has 2 brushes and found that the rear bearing had seized. I was planning on getting a new motor but hell if I can spruce this one up and save $350 what the hell right? The motor guts seem to be in pretty good shape. Some surface rust but the windings look ok and there is nothing visibly damaged, besides the bearing race seized to the shaft.

It is a splash lubricated piston compressor with a primary and secondary piston. The primary is maybe 2.5-3" diameter and the secondary is maybe 1.5" diameter. The air transfers in large copper tubing with heat fins on it. It looks a lot like this Quincy http://www.quincycompressor.com/PLT-cutaway-lrg.jpg.

The company that made it is Gilbert and Barker MFG Canada. Looks like this company has morphed several times and now mainly makes gas station pumps etc.

How can you determine the HP required to run the pump?

How much does a motor rebuild in the 5-10hp range cost? To my eyes it doesn't even need to be rewound.
 

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#3 ·
Cost on an electric motor rebuild? Call an electric motor rebuild shop. :laugh:

As to the HP required to run an air pump, that would be about 1.5 motor HP for about each 5 cfm @ 90 psi out of a typical pump.

Typical 60 gallon compressor tanks -usually- use about a 3-5 HP motor.

As to the two wire set-up, if the motor is old it might use just two wires and not have a safety ground wire (green wire in the current world).
 
Discussion starter · #4 ·
Even without the ground wire it is still weird that is was run on 2 wires. Assuming that it should be 220V for 220V (not a welder) you would need 2 blacks and a white, plus the ground, correct? But then again it does only have 2 brushes. How does the negative play into brushes? Is the negative a brush of it's own or are the brushes both hot and the negative comes out some other way?
 
#6 ·
salem,

220-240V single-phase AC is just two hots. No neutral needed, no ground needed. Two wires does it all.

For things that -also- use 120V AC while they are using the 240V AC, current Code says you need the two hots (for the 240V) -and- a neutral (to get the 120V). Current code also says you need a green/bare ground wire. So a 'recent' 240V household electric stove or clothes dryer has 4 wire: hot, hot, neutral, and ground.

But a 240V electric motor doesn't need 120V, so no neutral need. And an 'old' 240V electric motor might not have had a ground wire.

Thus an 'old' 240V single-phase (or DC if it is indeed a DC motor) motor just 'needs' two wires.
 
Discussion starter · #7 ·
Ah ha. That makes sense. Pretty small wire going into the motor too, maybe #12.

Talked to the motor shop in town and he said as long as nothing is totally blown or destroyed it should only be $100 or so to figure out what it is and get it running again. Better than $350 for a new motor that I would need a new pulley set for and may not even be the right HP rating.
 
#8 ·
I can't help withthe motor, but from your description it sounds like you have a 2 stage compressor rather than a single stage compressor. That means you'll probably get 175 PSI from it, as opposed to the 125 or so that you'd get from a single stage comp. The down side is that they usually make a bit less cfm at say 90 psi than the 2 cylinder single stage units.
 
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#9 ·
salem747 said:
Even without the ground wire it is still weird that is was run on 2 wires. Assuming that it should be 220V for 220V (not a welder) you would need 2 blacks and a white, plus the ground, correct?

But then again it does only have 2 brushes. How does the negative play into brushes? Is the negative a brush of it's own or are the brushes both hot and the negative comes out some other way?
Click to expand...
As previously posted, there's no need for a neutral connection; just two lines (hots) are necessary for run; for safety there's usually an equipment ground.

The brushes are only a factor during starts, they are connected only to each other, and do not connect to any line leads.

Be careful about running the motor without a load, it can overspeed.

Good Luck
 
Discussion starter · #10 ·
For $100 I am going to leave it up to the "experts" no experience with this outfit but they have a storefront etc. He figures he can tell me the hp rating by the frame and get it going again for $100ish.
 
Discussion starter · #11 ·
OK, so I have traced down what happened to the air compressor part of GIlbert & Barker known today as Gilbarco. It became Quincy compressor! No wonder the Quincy Max 5hp looks identical!

Gilbarco forwarded me to Quincy but Quincy has no records of compressors going back that far so it is sort of a dead end. But even the bolt patterns on the Quincy Max look exactly the same from what I have found. I wonder if I could get real drawings and confirm the measurements. I could maybe even use some of the same parts as a new Quincy!
 
#12 · (Edited)
Quincy compressors are the best. If you can't get that motor running you should just be able to get a set of taper-lok sheaves and any electric motor that meets the horsepower requirements. If you want to rebuild the motor, start by throwing a set of brushes at it. Bring in the remenants of the old ones. I have a local shop called Advanced Carbon Products. You don't even need to know the original dimensions. Just bring in the old ones and they'll make new ones while you wait at a cost of about $9 for a pair.

If you intend to try to use new Quincy parts on it, know that the basic compressor generall doesn't change but over they years Quincy has made many changes to the unloaders, valves, and oil pumps. They new assemblies can typically be bolted on to the old units but you will approach the cost of a new unit if you try to upgrade. We use the Quincy 325's exclusively at work. To rebuild one costs around $1500. A new one costs $1700 delivered.
 
Discussion starter · #13 ·
The motor is at the rewind shop right now. The guy said if it can be fixed up that it is the very best way to go. He says they stopped making motors with those big cast iron casings because it costs too much. He said a 5hp that I would buy off the shelf wouldn't last long and that I would need a heavy duty motor to make it happen. He thought it could either be 3 or 5 hp.
 
Discussion starter · #14 ·
OK, motor all fixed up, new bearings, inside cleaned and painted were necessary, outside painted, $40!

It is a 3hp motor, the motor guys figure a 25A circuit would probably work but 30A would be better. He showed me how to change the rotation if necessary, pretty easy to do, so on to the receiver and the pump!
 
#15 ·
salem747 said:
OK, motor all fixed up, new bearings, inside cleaned and painted were necessary, outside painted, $40!

It is a 3hp motor, the motor guys figure a 25A circuit would probably work but 30A would be better. He showed me how to change the rotation if necessary, pretty easy to do. . .
Click to expand...
Good deal!

Let me guess... the motor is reversed by clocking the brush holder?

Revulsion (okay, repulsion :laugh:) start motors have a very low starting current draw, that's what the shorted brushes are all about.

When do we see pictures of the pump?

Good Luck
 
#16 ·
$40 isn't bad. I tried to have a 7.5 hp motor rewound not long ago but the quote came back at $2400.

You can still get decent motors. Look for TEFC or totally enclosed fan cooled motors. These are typically the heavy duty cast iron type. Baldor/Reliance and WEG are considered the best at this moment.
 
Discussion starter · #17 ·
My company does work with this place so he just charged me for parts. I wish I knew what motor it is ie brand etc. They didn't have to rewind it, obviously that would be a LOT more, just bearings, some paint, some varnish and a few screws.

Yes there is an inspection plate that you open and there is a screw that you loosen and then you line up another set of marks on the brush holder.

The motor guys said this thing will have a really low starting inrush. Running no load at the shop on 230V it was drawing about 9 amps. He said it would be hard to find a motor that would last like this one. I really want to weigh it, it's friggin HEAVY!
 
Discussion starter · #18 ·
OK. So I figured out how old this thing is. It was certified with a CRN number. This is the number that registers the vessel as a pressure vessel in Canada. As you can sort of see in the picture that happened in 1958!!! My Dad was 11 when this thing was made! Anyway, I dug into the pump today and started cleaning it up and polishing the mating surfaces. It's a very simple design, but hella strong looking, fully cast cases and forged rods. The rings look pretty good but I don't know where I would get a ring gap spec for something like this. I am going to try and dig up a copy of the Quincy manual/parts list that "looks" the same, maybe some of the info would be useful, maybe not. My only problem is how do I blast and paint this compressor, well I need a compressor to do that, maybe I should find an old one and fix it up? You see my problem. I might do some of this stuff at our North Bay shop.

PS, Moly anti-seize will be applied liberally to the reassemble of this puppy!
 

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