dual voltage motor issue

[broncobowsher]

I think you are correct.

 

[rjack321]

120V and it runs

 

[rjack321]

It runs, builds pressure, cut in and cut out are good. But it seems "slow". Anyone have any good ideas on how to test the CFM and compare to the rated output? Its supposedly 5cfm but my guess is its pumping about 3

 

[tbone1004]

It runs, builds pressure, cut in and cut out are good. But it seems "slow". Anyone have any good ideas on how to test the CFM and compare to the rated output? Its supposedly 5cfm but my guess is its pumping about 3

if it's on a tank, just time it to fill the tank. i.e. an 80g tank is 10.69cf, 100psi=6.9bar, so 74cf at 100psi. Time how long it takes to get there and you get cfm.
If it's a true 3hp motor though, it should be doing 10-12cfm though. That said, you can't run a 3hp motor on a normal wall outlet since the amp draw is going to be close to double what a normal wall circuit can do, so there is that to consider.
17.6a on 120v is around 3hp, but that means the motor is consuming about 3hp, not making about 3hp which is irritating. Realistically it means it will be around 60% efficient, so making around 1.8hp maybe 2? Either way that should still be around 8cfm.

If the motor is turning properly and it the compressor RPM is to spec, then any drop in CFM is going to be due to leaks somewhere. Usually in the valves.

 

[rjack321]

if it's on a tank, just time it to fill the tank. i.e. an 80g tank is 10.69cf, 100psi=6.9bar, so 74cf at 100psi. Time how long it takes to get there and you get cfm.
If it's a 3hp motor though, it should be doing 10-12cfm though...

Negative on 10cfm

Free air is close to 10cfm IIRC
5cfm on the plate. This isnt exactly it but close
Eagle P3120H1-CC 3-HP 20-Gallon Belt Drive Cast-Iron Air Compressor

 

[tbone1004]

Negative on 10cfm

Free air is close to 10cfm IIRC
5cfm on the plate. This isnt exactly it but close
Eagle P3120H1-CC 3-HP 20-Gallon Belt Drive Cast-Iron Air Compressor

that's the second half of my post. It's consuming 3hp from the power outlet, but it's only actually making somewhere between 1.5-2hp. Strategic marketing.

Either way you'll have to find the specs on the pump itself if it's cast on there somewhere. Find out the rpm and validate the rpm, and check the charge times. If the rpm is right and the charge time is off, then check the intake air filter. If that doesn't fix it, then you need to do a valve job and potentially a ring job...

 

[rjack321]

So it says 12cfm on the plate but I have seen almost this exact model from a company in California advertised as 5cfm / 12cfm FA. So I think that's the difference.

But its only drawing 17 amps at 120V so its not a true 3hp either

Current output is 3cfm, which isnt terrible considering it was built in 1989. Now if I could only refind that company in the LA area that seemed to be the original manufacturer. This one is rebranded "acme" from a now defunct company in TN

 

[tbone1004]

So it says 12cfm on the plate but I have seen almost this exact model from a company in California advertised as 5cfm / 12cfm FA. So I think that's the difference.

But its only drawing 17 amps at 120V so its not a true 3hp either

Current output is 3cfm, which isnt terrible considering it was built in 1989. Now if I could only refind that company in the LA area that seemed to be the original manufacturer. This one is rebranded "acme" from a now defunct company in TN

good luck, but the general rule is 3cfm/hp at 90psi for smaller pumps and up to 4cfm on big pumps. Out of curiosity have you tried removing the intake filter and checking it there?

 

[rjack321]

good luck, but the general rule is 3cfm/hp at 90psi for smaller pumps and up to 4cfm on big pumps. Out of curiosity have you tried removing the intake filter and checking it there?

Hard to tell how grungy it is. I might just replace it. I'm kind of getting sick of putting money into this auction find.

 

[tbone1004]

Hard to tell how grungy it is. I might just replace it. I'm kind of getting sick of putting money into this auction find.

Take it off altogether. See if it changes the speed. Will be wicked loud, but so be it. If you're going to replace it, something like a Solberg may be in order which will help quiet it down.