Champion 80 gallon Restomod has begun

[Hohn]

Here are some estimates of the improved compressor performance by running at constant power and then derating as pressure rises.

Let's assume we never load the motor more than Champion does, and we'll tie the output to the motor load at 17.2 SCFM at 175psi.




And if we discover that Champion is significantly under loading the motor against FLA and we can run it 10% harder?




The VFD lets us run the pump as fast as the 7.5hp models and deliver similar (or more) flow--but as pressure rises, we can no longer sustain that flow within motor load limits. It's possible, however, that the existing system margins will allow 7.5hp flow rates up to usefully high line pressures-- enough to sustain a blast cabinet or similar as if it was actually a 7.5hp compressor.

The derate for motor protection comes in only above pressures that are already sufficient for almost all the tools I use.

A VFD cannot turn a 5hp compressor into a 7.5hp compressor. But it can probably make enough of a difference in your actual working pressure range that it's nearly a 7.5hp compressor in performance.

Which I think is pretty cool.

 

[Hohn]

Sounds good. I feel since you're going that far, a cheap 12v rad fan controlled by the VFD to cool everything for x amount of time once the motor stops would be a cool addition...

Literally.

I'm thinking of a couple related enhancements like having an air mover blowing on the motor/pump since the air flow of the existing flywheel and ODP motor is rather pathetic.

THis would also decouple the cooling function from the work of the compressor. I like the idea that the compressor doesn't have to pull power to earn a little cooling. Seems counterproductive in some ways.

 

[Hohn]

Another tweak I'm thinking about doing is a remote air intake. This would remove the air inlet from a lot of the compressor heat and improve volumetric efficiency slightly while also letting me enclose the air filter in a sound deadening box. If you look at how the Eaton "Silent air" units are configured it's nothing special-- use a long hose to draw air from a sound-deadened box

 

[Jswain]

Bonus from drawing air from a clean air space and never getting the grinding dust etc in the filter

 

[Hohn]

And now we have a backup/aux pump. Locally seller had an R15 that was very long in tooth and badly in need of some attention. But for just over $100, I couldn’t resist.



I’m thinking a basemount conversion or perhaps an unconventional vertical base mount (think appliance dolly air compressor with a 6-50 plug).

Unlike the R15 that came on the titular compressor that is the subject of this thread, this guy seems to be quite a bit older and much worse off. She’s going to get the full disassembly and rebuild, I think.

 

[finn]

That’s got the round fins around the barrel, so that confirms it’s an oldie. My R15 has those same round fins and was built in 1970 or 71, per the tank date code. Mine is “numbers matching”, ie the S/N is stamped on the pump and tank tag.

I think there’s a S/n range to build year list somewhere on the web, if you’re interested.

 

[Hohn]

That’s got the round fins around the barrel, so that confirms it’s an oldie. My R15 has those same round fins and was built in 1970 or 71, per the tank date code. Mine is “numbers matching”, ie the S/N is stamped on the pump and tank tag.

I think there’s a S/n range to build year list somewhere on the web, if you’re interested.

Can you highlight the area you are discussing?

I can’t see the difference between this old one and the replacement part:





My other R15 on the other compressor was made in 2002 and seems the same?

 

[finn]

Can you highlight the area you are discussing?

I can’t see the difference between this old one and the replacement part:





My other R15 on the other compressor was made in 2002 and seems the same?

Well, now I’m confused. I’m getting my information from three sources: Threads on the Practical Machinist forum; Threads from here on The Garage Journal; and my somewhat fallible memory from when I was trying to figure out exactly what compressor I bought (a Champion R15.

They came in 3 versions, R15, R15A, and R15B. Mine is an R15.

As to the differences, it’s largely valves, access to the rod bearings, number of rings, intake manifold design, and some I can’t remember.

The cylinder cooling fins went from rounded to squarish, and back to roundish, according to one post.

I’m not an expert, though.

I distinctly recall looking up the build era on mine in
some Champion service publication. I didn’t copy the link at the time though.

AI says it can identify yours given the S/N and date on the tank. My tank and pump S/N match.