Champion 80 gallon Restomod has begun

[Hohn]

I couldn’t resist the chance to get a project and a major compressor upgrade at the same time.

Local seller had a Champion VR5-8 for $200 with “an electrical issue.” I figure it’s probably a motor issue of starting cap or something. If the tank and pump are good, it’s worth the $200 to me.

Turns out, it’s got a 3ph motor which I’m sure is useful in some cases, but as a home gamer, not as useful to me. I’ll be swapping the motor to single phase. Obvious not a “starting cap” issue.

It’s got an oil level monitoring setup too apparently. I might remove this if I can’t get it to stop seeping. Pictured is a “the guy you want to know” and his son/helper.

 

[Hohn]

Can anyone tell me what this part is? It seems to have been disconnected as there are open ports on it for compression fittings where you’d plumb some tubing.

It’s just undeneath the part of the pump that houses the centrifugal unloader.

 

[larry4406]

Nice deal!

Swapping that 3-ph to single phase should be easy enough.

 

[manwithtools]

Another option is a VFD. Might be cheaper than a 5hp single phase motor.

 

[larry4406]

Another option is a VFD. Might be cheaper than a 5hp single phase motor.

Or repurpose the 3ph motor with VFD into a grinder although it’s 1725 rpm might not be desirable.

I thought there were posts here that seemed to frown on VFD’s for compressors.

 

[manwithtools]

I thought there were posts here that seemed to frown on VFD’s for compressors.

This is GJ after all , no doubt someone would post negatively on using a VFD on a compressor . I can't think of a reason a VFD would not work, compressor should have an unloader so start is not high current. It would take a little bit of wiring work to the right inputs on the VFD from the pressure switch, but not terrible.

Switching the 3 phase motor to a single phase motor is going to require some small wiring changes to the motor starter overloads and probably changing out the overloads due to the higher amperage of the single phase motor.

 

[Jswain]

I'll be the first to say, you ****!

 

[larry4406]

I'll be the first to say, you ****!

Yes, the suckage is high with this one...

 

[LopezBart]

Envious - that was a great deal.

A VFD will let your program a soft start; this can help reduce the inrush current a lot which is nice. Remember that one never disconnects the VFD from the motor; the pressure switch should be connected to the on-off terminals on the VFD. A name brand 5 hp VFD that will take single phase input isn't inexpensive, but it's cheaper than a 5 hp single phase 17xx rpm motor of similar quality to the 3 phase one that's on there now.

 

[Fixr]

I have essentially the same compressor. It came with a 3-phase motor, and at the time around 15 years ago, reasonably priced 5hp VFDs weren't really a thing yet, so I bought a Baldor single phase motor and a new contactor. If I were in the same situation today, I would absolutely go with a VFD for the soft start and variable speed, and I'm guessing the VFD would be cheaper than a new Baldor single phase motor now.. Most of the time I would run it near the lowest recommended pump speed to keep the noise level down, and only crank it up for high-demand occasions.

 

[metalmagpie]

Can anyone tell me what this part is? It seems to have been disconnected as there are open ports on it for compression fittings where you’d plumb some tubing.

It’s just undeneath the part of the pump that houses the centrifugal unloader.

That is an automatic tank drain valve. See the Champion document:

https://nwnative.us/Drain.pdf

 

[csp]

VFD will need to be rated at 2x the HP of the motor.

 

[Hohn]

That is an automatic tank drain valve. See the Champion document:

https://nwnative.us/Drain.pdf

Thank you! It was disconnected at some point at the tank drain at the bottom is manual, a mini ball valve.

If only I could figure out what that tubing teed off the side of the tank plumbed to the unloader does.

 

[engineer2]

The oil level switches on Champion compressors can be troublesome. We had one fail at work. PITA to replace, so the shop guys just bypassed it. I told them if they mind the oil change intervals all will be good for now.

 

[Hohn]

Switching the 3 phase motor to a single phase motor is going to require some small wiring changes to the motor starter overloads and probably changing out the overloads due to the higher amperage of the single phase motor.

The motor starter will need more than that—it’s entirely missing. The contents of the electrical box were gutted. Opening revealed just the three power wires to the motor and two wires from the oil level monitor.

 

[Hohn]

The oil level switches on Champion compressors can be troublesome. We had one fail at work. PITA to replace, so the shop guys just bypassed it. I told them if they mind the oil change intervals all will be good for now.

I’m tempted to remove and plug, it seems to be the source of a leak. As a homeowner, I could go YEARS on a good synthetic iso 100.

 

[engineer2]

Champion says 500 hours for an oil change interval. I put hour meters on ours so the plant guys can keep an eye on it. They've been pretty good about it.
We have two Champion compressors on an alternating relay. Compressor A alternately runs with compressor B. If one compressor fails then they can switch to the one working. The plant needs 100% reliability. If both fail, we have a portable compressor we can hook up. The plant runs 40 hours per week but they leave the compressors on 24/7 due to the nitrogen generator on the system.

 

[PoorUB]

Or repurpose the 3ph motor with VFD into a grinder although it’s 1725 rpm might not be desirable.

I thought there were posts here that seemed to frown on VFD’s for compressors.

I have messed with a VFD on a 5 HP air compressor. I had the VFD already so it seemed natural. One big problem I ran into is a compressor runs at pretty much full load from the start. You might be able to "soft start" the motor, but the pump will be compressing air almost instantly, so a soft start has to be very short duration.

Or you can rig up and unloader on the discharge line of the compressor. I shopped for one. You will need a valve that will handle the heat of the compressor discharge and the pressure. Shopping for a valve of a working pressure of 175 PSI and 250-300 degrees was pretty much a loss. If I did find one it was a few hundred dollars. so now for a 5HP motor you need a 1PH in and 3PH out, about $500, and an expensive valve. You may as well buy a 5 HP 1PH motor.

 

[PoorUB]

VFD will need to be rated at 2x the HP of the motor.

You can buy a VFD that is rated 5 HP, 1PH in, and 3PH out.

 

[manwithtools]

Or you can rig up and unloader on the discharge line of the compressor.

All belt driven compressors I've ever dealt with have built in unloaders. Should be able to set VFD for a very short ramp time and have it work fine. There are countless applications where VFD's start motors that are fully loaded.

 

[metalmagpie]

All belt driven compressors I've ever dealt with have built in unloaders.

That Champion pump has a robust centrifugal unloader. After each pumping cycle after the motor stops when the tank is fully pressurized, you hear a distinct hiss of escaping air as the unloader releases pressure.

 

[Hohn]

If I went the VFD route, would that alleviate the utility of a contactor/starter? I was thinking you’d still need a way to take the switching load off the pressure switch.

Also, I’m sure if I sized the vfd to handle 7.5hp, it would be ok on 5hp. Correct me if I’m wrong.

 

[manwithtools]

If I went the VFD route, would that alleviate the utility of a contactor/starter? I was thinking you’d still need a way to take the switching load off the pressure switch.

Also, I’m sure if I sized the vfd to handle 7.5hp, it would be ok on 5hp. Correct me if I’m wrong.

If you use a VFD, no contactor is necessary. The pressure switch would wire in to an input on the VFD, signaling it to start the motor. When the pressure switch is satisfied the VFD will turn off the output to the motor.

You can absolutely use a 7.5 hp VFD on a 5 hp motor. The VFD has programable parameters to set the hp limit of the attached motor. Many parameters are programmable - motor speed (typically multiple speeds depending on inputs), start ramp time, stop ramp time, overcurrent detection, over/under voltage detection, etc.

 

[PoorUB]

All belt driven compressors I've ever dealt with have built in unloaders. Should be able to set VFD for a very short ramp time and have it work fine. There are countless applications where VFD's start motors that are fully loaded.

I worked with VFD's for about twenty years. I couldn't make one work on my compressor. It didn't make any difference what I did, the VFD would trip on overload. I removed the discharge line from the compressor it started just fine.

The compressor unloader dumps the air from the compressor head on shut down. They are closed off on start up. On start up, a couple pump revolutions and the compressor is running at full load.

All I am saying is I couldn't make it work, with twenty years of working on VFD's, so lets recommend it to a guy with no experience and see if he can figure it out.

 

[PoorUB]

If I went the VFD route, would that alleviate the utility of a contactor/starter? I was thinking you’d still need a way to take the switching load off the pressure switch.

Also, I’m sure if I sized the vfd to handle 7.5hp, it would be ok on 5hp. Correct me if I’m wrong.

The VFD becomes your contactor/stater. Just wire the pressure switch to the start command on the VFD.

Watch the ratings on a VFD. Usually they need to be two times over rated to run a 3PH motor on 1PH, but there might be one or two manufactures with a different way of rating, so buyer beware.

I just looked for a 1PH to 3PH VFD and any of the ones I found said 10 HP on 3PH incoming power or 5 HP on 1PH incoming power.

I also shopped around a bit and you can find 5 HP 1PH motors for a little more money than a VFD.

I like VFDs, I have one on my drill press, but I use it for variable speeds. On a compressor I don't see the point as it runs on one speed.

 

[Jswain]

If you swap motors you also have the 3ph motor to repurpose or sell.

You already got a smoking deal, a quality motor & new magnetic starter won't break the deal. You may be up to the cost of a box store compressor, but you'll have something much much better.

 

[Firebrick43]

I worked with VFD's for about twenty years. I couldn't make one work on my compressor. It didn't make any difference what I did, the VFD would trip on overload. I removed the discharge line from the compressor it started just fine.

The compressor unloader dumps the air from the compressor head on shut down. They are closed off on start up. On start up, a couple pump revolutions and the compressor is running at full load.

All I am saying is I couldn't make it work, with twenty years of working on VFD's, so lets recommend it to a guy with no experience and see if he can figure it out.

I agree with Manwithtools on unloaders. Every larger piston compressor I have seen has an unloader of some kind and the OPs has a centrifugal unloader.

The question is why yours didn't have one?

 

[manwithtools]

All I am saying is I couldn't make it work, with twenty years of working on VFD's,

Well, I've got over 40 years working with VFD's, maybe I should give it a go.

I'm suspecting that the VFD you used may not of had enough current overhead available. One sure fire way to overcome your challenge would be to add a solenoid to the unloader circuit and have the VFD's output close the solenoid once the motor is "at speed".

 

[PoorUB]

Well, I've got over 40 years working with VFD's, maybe I should give it a go.

I'm suspecting that the VFD you used may not of had enough current overhead available. One sure fire way to overcome your challenge would be to add a solenoid to the unloader circuit and have the VFD's output close the solenoid once the motor is "at speed".

I mentioned doing that and finding a valve to handle 175 PSI and the high temps of the discharge got terribly expensive.

 

[PoorUB]

I agree with Manwithtools on unloaders. Every larger piston compressor I have seen has an unloader of some kind and the OPs has a centrifugal unloader.

The question is why yours didn't have one?

Mine has an unloader. The unloader just dumps the compressed air in the head and discharge line. It does nothing at start up, the compressor just has the empty head and discharge line. How many revolutions does it take to bring the discharge line up to pressure? Not many, maybe two revolutions.

If it has a centrifugal unloader that might be different, but not many compressors do.

 

[Firebrick43]

Mine has an unloader. The unloader just dumps the compressed air in the head and discharge line. It does nothing at start up, the compressor just has the empty head and discharge line. How many revolutions does it take to bring the discharge line up to pressure? Not many, maybe two revolutions.

If it has a centrifugal unloader that might be different, but not many compressors do.

Sorry, I guess I misunderstood you on what your compressor had installed. I still don't know what kind of unloader you have? Is it one that is part of the pressure switch (pumptrol or similar)

Or a solenoid operated diaphragm valve (like an asco)?

An unloader that's part of the electric pressure switch absolutely helps in startup, that is why its installed. And a few revolutions is a tremendous help in startup torque. They are not as effective as a centrifugal unloader as it can keep unloading till the force of the weights overcome the springs that keep it unloading. I cant speak to the issues that you were having as I wasn't involved, but many have used VFD's successfully to run compressors.

Or you can rig up and unloader on the discharge line of the compressor. I shopped for one. You will need a valve that will handle the heat of the compressor discharge and the pressure.
Shopping for a valve of a working pressure of 175 PSI and 250-300 degrees was pretty much a loss. If I did find one it was a few hundred dollars. so now for a 5HP motor you need a 1PH in and 3PH out, about $500, and an expensive valve. You may as well buy a 5 HP 1PH motor.

There is no reason it has to have a 300 degree rating. No one mounts it directly on the output of the compressor that I have seen. Any decent compressor is going to have an aftercooler before the tubing takes the air to the tank.

You tee the valve into the line at the check valve inlet to the tank, it doesn't have air flowing through the unloader constantly. The mass of the tank also keeps it from getting that warm. I can lay my hand without any discomfort on all the solenoid unloaders systems I have used. And when it releases air at the end of a cycle the air expanding cools it as well.

 

[Hohn]

If you swap motors you also have the 3ph motor to repurpose or sell.

You already got a smoking deal, a quality motor & new magnetic starter won't break the deal. You may be up to the cost of a box store compressor, but you'll have something much much better.

I’m leaning this direction also. As cool as it would be to have a VFD or be able to use the existing motor, I think I’d be happiest just buying a 7.5hp single phase motor and starter. It’s simple and proven.

 

[ericm]

I’m leaning this direction also. As cool as it would be to have a VFD or be able to use the existing motor, I think I’d be happiest just buying a 7.5hp single phase motor and starter. It’s simple and proven.

Why 7.5hp when the original was 5?

 

[Jswain]

Why 7.5hp when the original was 5?

Pump might be rated for more cfm with 7.5hp

Edit: https://pacificaircompressors.com/p...LXCpY0wOa9Q_VrIISGqNZpnCGU8pF_-jDLxEfQ9a41Mtr

If that's the pump is like 23.7cfm with 7.5hp and 17cfm with 5hp.

Worthy upgrade if you have the power

 

[Jswain]

Even more of a reason to swap the motors.

 

[ericm]

Pump might be rated for more cfm with 7.5hp

Edit: https://pacificaircompressors.com/p...LXCpY0wOa9Q_VrIISGqNZpnCGU8pF_-jDLxEfQ9a41Mtr

If that's the pump is like 23.7cfm with 7.5hp and 17cfm with 5hp.

Worthy upgrade if you have the power

Oh of course. Would the OP also need to change the pulleys to run the pump faster to get the added CFM?

 

[Jswain]

Oh of course. Would the OP also need to change the pulleys to run the pump faster to get the added CFM?

Pumps rated for 3-7.5hp and 440-990rpm with 9.7-23.4cfm. So yes, everything would scale relatively.

 

[micromind]

A few things about changing from 5HP to 7.5HP;

The 5HP is usually a NEMA 184T frame. The 7.5 is 213T. They are different.......

The bolt holes along the length of the motor are 184T = 4.5", and sometimes 5.5" 7.5 = 5.5" and sometimes 7". Make sure you have slots in the baseplate that are 5.5" or 7" center-to-center.

The 184T shaft diameter is 1 - 1/8". The 213T is 1 - 3/8".

If you use the same belt, the 7.5 motor will be closer to the pump. (Larger pulley) If there's presently room from the motor to the end of the slot, you might be ok with the original belt. If not, you'll need a longer belt.

Champion tends to run their motors pretty hard, as evidenced by the last one burning up. I usually go one pulley size smaller than the book states. Very little reduction in air delivery and the motor will last longer.

 

[walta]

Before you spend a ton of money for the rare 7.5 HP 1725 RPM motor. Pressure test the tank and get a smaller motor to spin the pump. Yes, it looks great but it could be a collection of failed parts.

Walta

 

[PoorUB]

I’m leaning this direction also. As cool as it would be to have a VFD or be able to use the existing motor, I think I’d be happiest just buying a 7.5hp single phase motor and starter. It’s simple and proven.

Do you have power to run a 7.5 HP motor? If you are on residential power the utility might frown running that large of motor. it is a bunch of inrush amps.