Who has an air compressor with a phase converter.

[claya]

So having done the 3PH to 1Ph conversion, and the drop in CFM. I could scavenge a 15hp 1ph motor if they exist, but not sure we have the ampacity to do that. Ma be stuck with 15HP 3ph. Consider we need a minimum of about 35CFM @ 90psi. The low limit on the machine is 78psi, but not sure I want to count on that to offset the lower CFM. Please advise on the following:

1. Twistair, 15HP (upgraded), 3ph, Maybe 35-40CFM: $1400 + 15hp motor.
2. Ingersol-Rand Variable speed, 15HP 60CFM, 3ph, (460V, needs a stepdown transformer), rebuild bad motor seal, $2600.
3. Compair, 10HP rotary vane, 41CFM, very low hours, $2850.

Which door would you chose? Keep in mind I would prefer this to be the last compressor I ever buy, and trying to reduce my energy cost as much as possible.

 

[LD1]

I'm not really an expert in the subject matter honestly. Don't know much at all about 10-20hp compressors.

I grew up on piston operated sub-$500 compressors. And familiar with 200hp + Kaiser's, sullairs, IR's, and Garner-denvers.

I just happened to aquire this twistair for free, with a locked up pump. It was in a remote corner of the plant where I work...and all it did was feed a few air lines to a few dock doors for filling them air bags to stabilize shipping loads. It locked up and we decided to plumb main plant air back there. Was told to toss this joy twistair in the scrap dumpster. So I asked if I could have it.

I figured even if the pump couldn't be rebuilt...it's a good 80 gallon tank.

So back to your matter.....
I don't know how compressor cfm is rated. IE: don't know how true the rating is to actual. But in my case....simply putting a single phase motor on in lieu of the 3ph ISN'T costing me any cfm. If I'm not actually making 40cfm....it's either due to 1. Intake and separator filters needing changed, 2. Pump vane wear 3. Or the 40cfm is a bit of an overrated number. Or 4. Any combination of the above.

And simply putting 15hp to it is NOT gonna make more cfm. When joy offered this compressor as a 60 cfm model and 15hp....they had different size pulleys that made the pump actually spin faster to make use of that extra power.

Knowing that you actually are going to consume 40cfm....I'd be leaning more toward a 60cfm compressor. IMO, it's never a good idea to buy "just enough". Because any slight variable...like a little age, or filters that aren't bran new....and you may suffer.

Not familiar with vane compressors either. My experience with them are limited to little Becker combo vacuum/compressors. But they are more high-volume, low pressure units. And the carbon vanes need replaced frequently. As do the filters that filter out that carbon powder out of the air stream. Don't know if any of that applies to a high pressure rotary vane or not.

 

[claya]

Trying to bump the CFM up to 28cfm at least. If I replace a 5hp motor with a 7hp, and increase the pulley ratio by some reasonable factor to increase the RPM and ( CFM), should I be concerned about overheating the air-end? The compressor (Kaeser SX6) has a temp monitor.

Didn't you do this with a Twistair?

So having done the 3PH to 1Ph conversion, and the drop in CFM. I could scavenge a 15hp 1ph motor if they exist, but not sure we have the ampacity to do that. Ma be stuck with 15HP 3ph. Consider we need a minimum of about 35CFM @ 90psi. The low limit on the machine is 78psi, but not sure I want to count on that to offset the lower CFM. Please advise on the following:

1. Twistair, 15HP (upgraded), 3ph, Maybe 35-40CFM: $1400 + 15hp motor.
2. Ingersol-Rand Variable speed, 15HP 60CFM, 3ph, (460V, needs a stepdown transformer), rebuild bad motor seal, $2600.
3. Compair, 10HP rotary vane, 41CFM, very low hours, $2850.

Which door would you chose? Keep in mind I would prefer this to be the last compressor I ever buy, and trying to reduce my energy cost as much as possible.

 

[LD1]

Trying to bump the CFM up to 28cfm at least. If I replace a 5hp motor with a 7hp, and increase the pulley ratio by some reasonable factor to increase the RPM and ( CFM), should I be concerned about overheating the air-end? The compressor (Kaeser SX6) has a temp monitor.

Didn't you do this with a Twistair?

No idea. No I didnt do it with the twistair. Twistair (JOY) did it. Because the 15hp-60cfm....10hp-40cfm, and 7.5hp-28cfm models all used the EXACT same air end. pulley ratios was the only difference.

The issue with you wanting to do this.....is I dont know kaeser compressors or models. You might overheat and burn it up, you might be fine.

Joy only seems comfortable getting 60cfm with 15 hp out of that specific air-end. If you had a 7.5hp or 10hp model....I see no problem overclocking it. But what if it was already a 15 and someone wanted a 20hp motor an spin it even faster???

You may already have the airend maxed out on that kaeser.....or it could be at the bottom. I just dont know. I'd consult the MFG