Air Compressor ?

[golferdude]

I have finally got my shop far enough along to be able to bring an air compressor from my father in-laws shop. He passed away as he was rebuilding the compressor. We actually went to his shop with him on oxygen so he could tell me about the compressor.

It is an westinghouse 2AVC compressor and an 80 gallon tank. He has a 5 hp, 3425 rpm motor for it.

It has been sitting for 5 years. I don't know alot about air compressors. He had me hand tighten the caps on each cylinder. On the inlet, it has the red plastic cap in the piece that needs to be tightened. I have inserted pics to show you what I am talking about. Do these get tightened to a specific torque or just tight?

Also, on the motor sitting for 5 years, is there anything that I should do prior to starting it? I will make sure it has new oil. Speaking of, what is best oil for this compressor?

Thanks

 

[Kaizen]

They sell compressor oil. no idea about the caps. I would make sure it turns over and the cylinder isn't stuck.

 

[Fixnair]

Tight as you can get them. Don't try & use the 3450 RPM motor with that compressor. It does not have enough starting torque to start that machine. Use an 1800 rpm motor.
Use ISO 68 hydraulic oil in the crankcase. Good old slow speed compressor. Use about an 8" dia motor sheave to achieve a pump speed of around 800 RPM.

 

[CGT80]

Man..........that is a really nice compressor.

At 800 RPM, it will chug along with a sound that might seem just a little noisy when you are right by it, but at 15 feet away, or on the other side of a garage wall, it is very quiet. Mine sits outside, and with the swamp cooler on and the side door open, I can not hear it run, but I feel it in the floor. My blast cabinet has the large TP tools tips that require 20-25 cfm, and at 100 psi, it will catch up, shut off, and then it takes a few minutes to reach low enough pressure to kick back on.

Do you have wrenches to fit the valve caps?

I had to make my own and tap them with a small sledge hammer to get them off. I still need to make a wrench for one of the HP caps.

That motor will not be ideal for that pump. Mine is a 5hp baldor at 1750 rpm, IIRC, and it will pull 164 amps on 240v for half a second on startup. It runs at 30 amps, which is a little over name plate but within the service factor. Mine will fill the 80 gallon tank in 5.5 minutes and will top off from 105-150 psi in 60 seconds or less. It puts out 20cfm, according to an online calculator.

The lines to the unloaders are wrong in this photo, so don't copy it. I have re run new lines. The unloaders on the valves get plumbed to the top port on the oil pump and the middle port goes to the tank. Bottom port is left open.

If you need more help, let me know. You can look up my profile and find my posts on this unit, or search for 2avc.

 

[golferdude]

Tight as you can get them. Don't try & use the 3450 RPM motor with that compressor. It does not have enough starting torque to start that machine. Use an 1800 rpm motor.
Use ISO 68 hydraulic oil in the crankcase. Good old slow speed compressor. Use about an 8" dia motor sheave to achieve a pump speed of around 800 RPM.

On the motor, I am trying to understand. Why wouldnt a 3450 motor work if I use a pulley to get the compressor spinning at 800 rpm? What would it damage?

If I have to buy a 1725 rpm motor, will it be worth the $250 premium to get a 7.5 hp motor? What will it buy me?

 

[golferdude]

Man..........that is a really nice compressor.

At 800 RPM, it will chug along with a sound that might seem just a little noisy when you are right by it, but at 15 feet away, or on the other side of a garage wall, it is very quiet. Mine sits outside, and with the swamp cooler on and the side door open, I can not hear it run, but I feel it in the floor. My blast cabinet has the large TP tools tips that require 20-25 cfm, and at 100 psi, it will catch up, shut off, and then it takes a few minutes to reach low enough pressure to kick back on.

Do you have wrenches to fit the valve caps?

I had to make my own and tap them with a small sledge hammer to get them off. I still need to make a wrench for one of the HP caps.

That motor will not be ideal for that pump. Mine is a 5hp baldor at 1750 rpm, IIRC, and it will pull 164 amps on 240v for half a second on startup. It runs at 30 amps, which is a little over name plate but within the service factor. Mine will fill the 80 gallon tank in 5.5 minutes and will top off from 105-150 psi in 60 seconds or less. It puts out 20cfm, according to an online calculator.

The lines to the unloaders are wrong in this photo, so don't copy it. I have re run new lines. The unloaders on the valves get plumbed to the top port on the oil pump and the middle port goes to the tank. Bottom port is left open.

Well I turned over the compressor and spins with no problem.

I have sockets that will fit the caps, might have to remove the brass fitting on top though. I also have a wrench that fits them.

On the lines to the unloaders, I have the old ones. I think I have figured out how they go.

 

[alwaysFlOoReD]

It's great that you are getting it running. He must have held you in good regard. Every time you use it you will think of him. A good legacy.

 

[CGT80]

On the motor, I am trying to understand. Why wouldnt a 3450 motor work if I use a pulley to get the compressor spinning at 800 rpm? What would it damage?

If I have to buy a 1725 rpm motor, will it be worth the $250 premium to get a 7.5 hp motor? What will it buy me?

Based on posts from others on this forum, a 1725 rpm motor will have more starting torque.

My compressor seems to start easy enough, even before I plumbed the unloaders so they would work correctly, and with the tank having 140 psi in it. Yes, there is a check valve between the pump and tank, and it is possible the pressure leaked out of the line coming off the head, but I don't think there is anything designed in this pump to let the air escape when the unloaders are not activated.

When air is applied to the unloader/valve, it opens that intake valve and it prevents the pump from making pressure or having to exert much force. There is no load on the pump. If the tank is empty, then there will not be air pressure to hold the valves open. This means that some air will be pumped into the tank, before the valves can be held open. If the pump is running and building oil pressure, the valves would not see pressure anyway, and with no pressure in the tank, there is little load on the pump. Where it would matter, is if the oil pump failed or the oil leaked internally. In that case, once enough pressure was developed, the valves would be held open to relieve the load on the pump to help prevent damage.

If you run a fast motor and it doesn't have enough torque, then you will overload the motor. The only way I know of to figure out if it is up to the task, is to try it. More torque means a motor that might be more forgiving if your pump speed is slightly higher.

This pump appears to be the same as a Leroi 400, which is only rated up to 5hp at 800 rpm. A 3hp motor would spin that pump at 600 rpm. Mine had the wrong pulley when I got it and it spun at roughly 600 rpm. It was very quiet at that speed. Running a higher hp motor will do nothing but give you a extra torque, if your pulleys are the wrong size, but spinning the pump fast to use that HP may be hard on the pump or even damaging to it. If it was the 440A, then it could be spun at 1100 rpm with a 7.5hp motor and it would make more air. I would only consider the 7.5 if you were considering a bigger pump to go with that motor, down the road. Otherwise, save the $250 and make sure you have the right size pulley.

 

[CGT80]

Here is the pulley I am using, at 8.25" OD
https://www.amazon.com/gp/product/B007YLTHGQ/?tag=atomicindus08-20

The insert: https://www.amazon.com/gp/product/B007YLTHGQ/?tag=atomicindus08-20

The belts A/4L size:
https://www.amazon.com/gp/product/B00E42D7H8/?tag=atomicindus08-20

This is for a 1725 motor with a 14.5" OD flywheel

I used an online calculator to figure out what size pulley to run and how long the belts needed to be, for the layout on my tank. I have not put a tachometer (don't have one) on the machine to verify the speed.

 

[TractorJeff]

Do the math on the pulleys for the speed and run the motor that is on it. He probably ran it for years the way it is. Wouldn't hurt to get the speed right which will affect the running motor amps.

 

[golferdude]

Here is the pulley I am using, at 8.25" OD
https://www.amazon.com/gp/product/B007YLTHGQ/?tag=atomicindus08-20

The insert: https://www.amazon.com/gp/product/B007YLTHGQ/?tag=atomicindus08-20

The belts A/4L size:
https://www.amazon.com/gp/product/B00E42D7H8/?tag=atomicindus08-20

This is for a 1725 motor with a 14.5" OD flywheel

I used an online calculator to figure out what size pulley to run and how long the belts needed to be, for the layout on my tank. I have not put a tachometer (don't have one) on the machine to verify the speed.

Thanks...I have a 17.5" flywheel, so it says a 8 1/8" small pulley, with a 1725 motor. Your insert and pully link above are the same, goes to the pulley. Can u let me know what insert u used?

Is there a brand of motor that is best, or what brand to stay away from?

 

[golferdude]

I have read where people think it is good to have a mag motor starter? Is it worth it?

Also, looking at a filter regulator, there are a lot of brands. I am looking for one that has a 1/2" inlet min. My airline is looped around the shop and is 3/4".

Thanks for all of your advice...appreciate it.

 

[CGT80]

1 3/8" "H" Pulley / Sheave Bushing for Leeson Power Drive Sheaves

Part Number HX1-3/8


https://www.amazon.com/gp/product/B007YLTP2W/?tag=atomicindus08-20


Of course, make sure that you get the insert for the size motor shaft you use.


Mag starter is recommended for 5hp motors and above, but if the motor has a reset button on it, some people will skip the mag starter. My motor does not have a reset, and I do not run a mag starter. When I got the machine, I cleaned the contacts on the pressure switch, which is an old squareD IIRC. The mag starter is on my list of to do items.


I like Baldor. Our mill/drill has one, this compressor has an old one, and my bench grinder is a 3ph baldor.


I would check amazon for a filter regulator. Our cnc plasma table has a campbell hausfield (spelling?) which is identical to the husky from home depot. My garage has the husky because they are easy to get, but hd didn't have the 3/8 version at the store I went to last time. A 5 micron water separator is good for the bulk and after that I run a motor guard m30 or m60 0.05 micron paper filter. This does a good job of keeping the air dry for plasma, blasting, and painting, but you have to exchange the filters and let them sit out to dry, periodically.

 

[golferdude]

Well I have been able to do a couple of things more on the compressor project.

On the tank, I wanted to put a piece of pipe on each end to set the tank in the air and spin the tank with gravel in it to clean the inside of loose rust. But the bottom only had a 1/4" pipe thread which wouldnt support holding the tank up. So I did it the hard way, put some gravel in the tank and rolled it around in my yard. Lol But it did a decent job. Then I stood it up, sealed every thing, filled it with water and used my pressure washer to raise the pressure to 400 psi. No leaks. Let it sit 4 hours, then lowered it to 175 and let it sit over night. So the tank is good to go.

I found out the motor my father in-law has is a Leeson 5 hp, 1740 rpm motor. So that is good. With my 17.5" compressor pulley, it needs a 8" motor pulley to spin the compressor 795 rpm. But I cant find an 8" double groove pulley. I found a 8 1/4" pulley, it makes the compressor spin 820 rpm. Or I can find a 7 3/4" pulley to get the compressor at 770 rpm. Is it better to go 770 or 820? Is there a good distance to have between the pulleys?

Thanks..

 

[redmondjp]

. . . With my 17.5" compressor pulley, it needs a 8" motor pulley to spin the compressor 795 rpm. But I cant find an 8" double groove pulley. I found a 8 1/4" pulley, it makes the compressor spin 820 rpm. Or I can find a 7 3/4" pulley to get the compressor at 770 rpm. Is it better to go 770 or 820? Is there a good distance to have between the pulleys?

Thanks..

Either pulley will work - I'd probably pick the 7 3/4" as that will lower the motor current at peak tank pressure a bit. Pulley distance isn't that critical, but the farther away, the more belt you get on the smaller pulley. Set it up like the factory-built units and you will be just fine.

 

[golferdude]

I am going to get my motor this weekend. Then I still have to paint the tank. Then hopefully I can start putting it together. fingers crossed. I do have a couple more questions.

1. I was going to put 2 safety valves on the tank. How do you size them? If I run the pressure to 175, do I put a 175 or a 200 safety valve? Also, should I get as large a thread safety valve or is 2 - 1/4" safety valves ok? Also, is there a specific location to locate them? I was going to put one on the top, towards the front where the pressure switch and gauge is going. Then the second one was just going in another opening in the tank.

2. I am going to get a magnetic starter. I have been looking at the Square D 8911dpsg32v09 one. I know there are cheaper priced ones out there, so is this the time it is wiser to spend the money once and not worry about it? If not, is there a recommended one out there?

3. There are small copper lines that run from the oil pump I believe, to the top of each cylinder. There isn't any other small copper lines that need to be installed is there? I attached a pic of the compressor - there are two ports with yellow plugs in them. One I assume is to connect the lines to the unloaders. Is the second one used to run a line to the pressure switch?



Thanks....

 

[golferdude]

I am getting close to finally powering up this compressor. I have to mount the mag starter and wire it 0, put the oil in, and power it up. Hopefully this weekend. Have a question on the oil.

On the ISO68 oil, does it matter what weight? I found some iso68 20 weight. Thanks. Will share my pics when I get it running. Thanks.