Just Bought This Air Compressor

[niferous]

I have a fairly small Craftsman air compressor that struggles just running a 1/2" impact gun. So much so that I don't really run it that often. I think this should be able to run just about any 1/2" or 3/4" impact tool I would use. Maybe even two at the same time. But I've never gotten too into air compressors so any input there would be helpful. The data plate says it is 15 CFM and 175 PSI.

I plan on running lines around my garage and also building a sound enclosure around it to keep my neighbors happy. Is steel pipe the best thing to run for permanent air lines? I have some 1" galvanized pipe and I also have some 250 psi air hose at my shop I could use as well. My plan is to run lines around my attic and then have a few outlets with some ball valves that can be hooked up to as needed.

Here are some photos:

 

[brianpgriset]

You have three phase power?

 

[softailgarage]

Yeah, that should run anything, looks like an old shop compressor, but you do need the power. Dont use galvanized pipe, the galvination(?) can peel off and damage things, use black pipe. If you build an enclosure make sure there's a way for air to get in freely.

 

[Daddyoneleg]

Nice, 15cfm at 175 will be a treat. Have you heard it run ?, hopefully it's slow and quite.

 

[niferous]

I do not have three phase power, I was planning on running a single to three phase inverter.

Thanks for the tip on using black pipe over galvanized. I may go with the 250 psi multi-purpose hose I have. I believe I have a few hundred feet of 3/4" and 1". Should I go ahead with the higher ID if I have it?

As far as an enclosure I'm going to read up on them as much as I can on hear.

I have not heard it run. It's kind of a gamble at just under $200. Hopefully it doesn't need much if any work. I too hope it's quiet.

 

[454ragtop]

For a compressor, I would recommend swapping the motor for a single phase motor. An inverter to run that would be very expensive, unless you got real lucky. Really no real advantage to driving this with an inverter, it's not like you want to vary the speed or change motor direction. That tag makes me think ex military/government.
Good luck, Jim

 

[niferous]

For a compressor, I would recommend swapping the motor for a single phase motor. An inverter to run that would be very expensive, unless you got real lucky. Really no real advantage to driving this with an inverter, it's not like you want to vary the speed or change motor direction. That tag makes me think ex military/government.
Good luck, Jim

I had thought about that as well. I just did a Google search for the inverter and found a bunch for under $300. Once I find out the specs on the motor I will call the guy where we get our electric motors from and see what he can do.

It is ex military. I bought it at a DRMO auction.

 

[unashamedlaborer]

That's a champion pump. Good unit. It's not 15cfm at 175psi. It's more like 15cfm at 100psi with a max pressure of 175psi. As previously stated it is really of no benefit to run a drive or a phase generator for the compressor. But you are going to have to pony up for a good single phase 5hp motor. Unless you get really lucky anyway. You are also going to need a mag starter in case you didn't know. If the unit came with one, pay attention to the overload setting/heater strip number. It is very likely that they will be undersized as it will be pulling more amperage on single phase. I run air systems in copper preferably and black iron if a customer insists. While you don't get the flaking coating with black iron you do get rust. Copper is cleaner in terms of corrosion and debris, plus it is a lot faster and easier to work with, especially if you want to add something later.

 

[454ragtop]

How many HP is the motor, looks like at least 5? Where are you finding inverters that big for under $300.?
Jim

 

[gtermini]

How many HP is the motor, looks like at least 5? Where are you finding inverters that big for under $300.?
Jim

Static phase converters are cheap. One would be perfectly well suited for this application. Enco was down for site maintenance, so I got the ad the old fashioned way. A medium duty unit would be fine provided the compressor is equipped with a tank check valve and pressure bleed off on the tank feed line between the check valve and the compressor head.

Greyson

 

[454ragtop]

A static phase converter is not an inverter, and won't deliver full rated HP, which you will need with a compressor. Makes no sense, probably half way to the cost of a single phase motor, which is the way to do it.
Jim

 

[gtermini]

A static phase converter is not an inverter, and won't deliver full rated HP, which you will need with a compressor. Makes no sense, probably half way to the cost of a single phase motor, which is the way to do it.
Jim

First off, a 3 ph inverter has absolutely nothing to do with phase generation.

https://www.google.com/#q=3+phase+inverter

Static phase converters work by using a combination of start and run capicitors to simulate enough of a 2nd and 3rd power phase to excite the rotor out of a locked-rotor condition and into motion. After the rotor is spinning the start capicitors are removed from the circuit and a run capicitor is used to balance the phase load for smoother motor operation. Since the ture power phases are lacking, the motor operates with a reduced operating power. The load in a compressor situation is mostly a starting load de to fighting the tank pressure and accelerating the pump flywheel. Static converters can have capicitors sized accordingly to overcome large starting loads. Once the compressor is running, the motor load should be well below the service factor rating of the motor and easily run by the proper size static converter. Static converters are not true phase generators, but a perfect 3ph is not necessary for a intermediate duty compressor.

There is lots written on true phase generation and capicitive load balance. Google is your friend. Most are grossly uinformed on the subject.

Greyson

 

[CNGsaves]

In hot and humid Houston, TX . . . I sure would not recommend you cheap out on your airline system and settle for hand-me-down rubber hose.

With that nice big compressor, you will definitely love a well-built air line system from black pipe steel that draws out all the moisture. See an excellent example of black-pipe air line system by fellow GJer . . . Strouty . . . at:

http://www.garagejournal.com/forum/showthread.php?t=214394&highlight=black+pipe

 

[454ragtop]

An "inverter" as I took it, is a variable frequency drive, or VFD, something I'm very familiar with, as I currently have 6 three phase machines using them to convert single phase power to 3 phase, as well as provide variable speed, and almost instant reversing. I'm familiar with static phase converters as well, and, IMHO think that band aid approach in this application will turn out to be a waste of money. In fact, I'll bet Phase-A-Matic themselves wouldn't recommend a 5 HP medium duty static inverter to run a 5 HP compressor.
Jim

 

[c39er]

"Dont use galvanized pipe, the galvination(?) can peel off and damage things, use black pipe."
Yep I get that stuff all over me when I shower and in my coffee water!

 

[niferous]

I found the specs online. Just for kicks I'm trying to find a motor and starter at work through the manufacturer that makes them for our centrifugal pump assemblies. I've also got my eyes on a static converter in case that doesn't work out.

In the meantime I'm trying to get more familiar with what all the specs mean. Is the pressure switch just what is used to adjust the outflow pressure of the compressor? I've got no idea what the last item is, the safety interstate valve.

 

[unashamedlaborer]

I found the specs online. Just for kicks I'm trying to find a motor and starter at work through the manufacturer that makes them for our centrifugal pump assemblies. I've also got my eyes on a static converter in case that doesn't work out.



In the meantime I'm trying to get more familiar with what all the specs mean. Is the pressure switch just what is used to adjust the outflow pressure of the compressor? I've got no idea what the last item is, the safety interstate valve.

Your mag starter will probably be fine, it's the overloads that are probably a little undersized. The pressure switch is a set of contacts that open and close when the pressure in the tank falls below the cut in setting and reaches the cut out setting. One contact is fed with 120v typically and the other wire from the other contact goes to the coil of the mag starter basically "commanding" the start and stop of the motor/pump. The interstage safety is a pressure relief valve just like a tank safety valve. It is located in the "interstage" which is the space between the low and high pressure cylinders. Also referred to as the intercooler. This safety should lift at no more than 45psi. As you r intercooler pressure should be about 30psi.

 

[dirtydogintex]

I disagree w/the advice to run black pipe instead of galvanized in the Houston (high humidity) area.

Most of the petrochem plants in the area also disagree.

 

[Trey T]

Drop in a 1700rpm Baldor or Leeson 5HP for 300-400$ and call it a day.

If you want to save money, the 3400rpm 5hp motors are about $100 lower.

 

[niferous]

Just to update everyone, I'm still working on this project. It sat at my warehouse for a few months while I went to North Dakota for work. I took everything apart to clean it up and paint it and right now I'm just waiting on the tank to get painted and it will be back together. Also the shaft seal on the back of the air compressor was leaking so I need to find a new one of those as well.

Here is the belt and pulleys off:

About to get painted:

Here is the air compressor taken apart to replace the rear shaft seal and paint the body:

The smaller piston has a little bit of surface rust on it, should I worry about that?

Also I'm leaning towards using stainless steel tubing for my lines. My company sells it so my cost is pretty low. Does anyone see a downside to using that? I was thinking 3/4" lines would be enough.

Finally I still haven't decided how I plan on powering this thing, there seems to be a lot of different opinions on that.

 

[b-body-bob]

Did you save the thick gasket between the crancase and the unloader housing? You'll need to know the thickness so you get the bearing preload back where it should be. When you get the gasket kit you'll see that it comes with several of differing thicknesses that you stack to get the thickness needed.

When I reassembled my Champion pump I had some trouble knocking the seal back in and had to rig up a tool from square tube and all-thread to press it in.

The old seal will have a standard seal number stamped into it that you can use to source a new part. You can order them from an auto parts supplier once you have that number.

I'd get a bit of emery cloth and buff the rust off that piston, but I wouldn't get all hung up over it if it's not bad.

Finally, did you make note of which way the bearing caps were facing? You have to install them so the slinger catches oil. I didn't pay attention while disassembling but was able to figure it out by noticing which way the crank turns. I then faced the slot in the slingers (just long roll pins) so they are toward the rotation so it grabs oil in the slot and slings as it rotates.

This is the thread where I built the seal jig and it also has the seal part number in it. Have fun
http://www.garagejournal.com/forum/showthread.php?t=225025

 

[bsaint]

I wouldn't bother with a three phase converter. Just buy a single phase 5 hp motor

Between the cost to buy and run the converter + run the compressor + the extra wiring, its more cost effective to sell the old motor and buy a single phase 5.

 

[kams1973]

I don't think stainless after the receiver would be an issue.

 

[C96]

The smaller piston has a little bit of surface rust on it, should I worry about that?

Rust on it?
What is the piston made out of if it has rust on it? weird

 

[bsaint]

Rust on it?
What is the piston made out of if it has rust on it? weird

High pressure pistons are 99% of the time steel because of the heat.

 

[b-body-bob]

Champion marketing material also makes it seem part of the reason they did it is it makes it easier to balance the weight of the small piston to the weight of the big one.

 

[C96]

High pressure pistons are 99% of the time steel because of the heat.

Just assumed stainless, my bad

 

[bsaint]

Oooooo I see. Ive never seen stainless pistons...

 

[niferous]

I wanted to come back to this thread as I've finally gotten the air compressor re-assembled and running. I wound up just buying a 5 HP motor as others suggested. One issue I'm having is that it appears the guy who helped me put this back together used coarse thread bolts for the 7/16" bolts that attach the head to the body. I asked him about it and he said he remembered that they were "really hard to thread in there but finally went in". Good intentions and all but now I've got oil leaking up through the bolts in the front of the compressor and I can't even tighten them. So I'm ordering a Helicoil thread repair kit in the right size (7/16-20") and will try removing the head and repairing the threads.

Also I noticed that I had a little bit of oil spitting out of the centrifugal unloader cover. At least I was thinking it was oil but I didn't even think that oil poured through there. Also the little crank case breather on the bottom of the centrifugal unloader had air coming out the whole time. Is that right? I thought that they only released air briefly when the motor and pump turned off so that any compressed air in the piston was relieved.

This is my first time working on an air compressor and I've learned a whole lot. Hopefully I can get these two issues fixed and it won't be the death of the pump. Thanks in advance for any help or tips that can be provided.

I took two photos of the unit in the little shed I made for it. You can see the bolt I took out to confirm that it was a coarse thread and not a fine thread like it should be.

 

[PT Doc]

Gotta love the really hard to thread comment and the fact that he continued anyway. Did you kick him in the nuts just for fun?

 

[CGT80]

Gotta love the really hard to thread comment and the fact that he continued anyway. Did you kick him in the nuts just for fun?

I couldn't have said it better!


How does the compressor perform, OP? Is it pretty quiet and does it keep up with all of your tools? What brand motor did you use?

 

[niferous]

He meant well and it was done by accident plus they do make thread repair kits so I can't be too hard on him. What are friends for?

 

[niferous]

I couldn't have said it better!


How does the compressor perform, OP? Is it pretty quiet and does it keep up with all of your tools? What brand motor did you use?

Other than leaking oil through the bolts it seems to be running just fine. I've yet to get it completely up to 175 psi though as the first time I started it I had some air leaks so I fixed those and then the second time I started it I noticed the leaks. I have a brand new air hammer and die grinder waiting to get a whirl.

The motor is a 5 HP Leeson.

 

[G_P]

Judging by the way that data tag is written, and the green color, that compressor came from the military.

 

[niferous]

Judging by the way that data tag is written, and the green color, that compressor came from the military.

It did. I bought it through DRMO.

 

[niferous]

So any thoughts on seeing oil coming out from the cover of the centrifugal unloader? I really didn't think that part was supposed to have oil flowing through it. Also the little crank case breather on the centrifugal unloader had air coming out of it while the unit was on. I thought air only escaped from there when it was off. Any thoughts on that? Thanks for any advice.

 

[G_P]

The centrifugal unloaded probably has a gasket sealing it to the crankcase which could be leaking, or a crankshaft seal might be leaking to let oil into that area.

 

[niferous]

I got all the items I need to repair everything so sometime this week I'll be getting it all taken a part and hopefully put back together right and running good and strong.

I actually got all the parts last week but we also had our twins born so they've been dominating our time but it's worth it.

 

[niferous]

Man I wish I could post an end result! So before I took everything apart the compressor was building up pressure easily. Now I took everything back apart (2nd time) and put it back together and the oil leaks did go away but now I it isn't building any pressure. It seems as though the compressor is running slow and the centrifugal unloader is open and therefore dumping air out. I let it run for about 25-30 minutes and all it produced was 40 PSI. I've got a friend coming over and I'll have him help me tighten the belts up to see if that helps. If not I'll have to take it off the tank and see about putting her back together again!

Edit to add: I forgot that when I went to first turn on the air compressor it didn't want to turn over and tripped the breaker. I had to bar it over by hand to get it going. The heat is unbearable today so it fired my brain and I forgot about that. My buddy came over and we got the belts nice and tight and still no better. I have to go out of town on Wednesday and will be gone until Friday or Saturday night. Hopefully this weekend I can get it diagnosed and fixed.

IF IT AIN'T BROKE DON'T FIX IT!!!!

 

[engineer031]

something is not right it should only take 5-6 mins to fill the tank.
Make sure you dont tighten the belts too much or it will wear the bearing you should have about an inch of play in the belts