Older speedaire/champion compressor

[sco44]

I just got a older speedaire 3z172. It looks to be the same as a champion s20 pump. I will be running it with a baldor 1phz 5hp 1725rpm and mag starter.

What rpm should I shoot for when picking the motor pulley? It shows max of 1000rpm. Should I get as close to that as possible?

max psi of 120? is it capable of running higher than this efficiently? I plan on a new pressure switch as well. Tank shows 200psi working pressure

Also, I can turn the pump over by hand, but don't really hear much of any groaning or popping. Should I be hearing something?

Link to the pump: https://m.grainger.com/mobile/product/CHAMPION-1-Stage-Splash-Lubricated-3Z172


-scott

 

[The Tool Tyrant]

Without doing any research on this pump, I can deduct by the fact that it has an air filter for each cylinder, that it's a single stage pump, so 120 psi is all you're going to get out of it. You need to find the sheave diameter on the pump in order to ascertain the drive sheave diameter.

Specs for the Champion S20 pump states sheave diameter of 16.5", so a 9.50" drive sheave would equal a pump RPM of 993.

You should be able to feel some compression, but being as it's a single stage pump, not a whole lot of resistance. you should be able to feel air exiting the discharge port / tube. Valve rebuild kits are readily avaliable for this pump and are quite easy to change out if needed...one of the great features of Champion pumps.

 

[454ragtop]

Everything is right there in the specs, says 5 HP, 7-1/4" pulley to get 788 pump RPM and 120 max pressure.

 

[sco44]

So no problems running the pump closer to max rpm than stock? Other than being a little louder obviously. I snagged it for 200$ so I figured it was a decent deal, based on the cost of the pump new.

 

[454ragtop]

There is a relationship between HP and pump RPM. Note they say to use a 4-1/8" pulley with a 3 hp motor, can't use the larger pulley because there isn't enough power. If you try to take the pump to 1000 RPM, for likely little to no gain, you may well need a 7.5 HP motor.

 

[sco44]

Gotcha, that makes sense. Surplus center has a 7.75" that fits the motor I plan to use. Looks like that would put me at 810rpm, pretty close to stock.

As far as being single stage and 120 psi. Why do I see many other single stage that run to 135. What is the limiting factor? Just curious.

 

[American Locomotive]

I've seen single stage pumps that run up to 155 PSI. You just lose efficiency at higher pressure.

 

[The Tool Tyrant]

Gotcha, that makes sense. Surplus center has a 7.75" that fits the motor I plan to use. Looks like that would put me at 810rpm, pretty close to stock.

As far as being single stage and 120 psi. Why do I see many other single stage that run to 135. What is the limiting factor? Just curious.

The specs I read state the pump is rated for 3-5 HP, so max rpm would be when using a 5 HP motor with the 9.5" drive sheave...using a smaller HP motor would require less RPM (lower gear ratio) in order for the motor to be able to 'pull' it.
It's no different than pulling a heavy load with a manual transmission in a gear too high for the engine to pull.
Another limiting factor is the maximum load the rods and crank were designed for. No different than increasing the compression ratio in your car engine. The pump parts are designed for a maximum load (PSI)...exceed this and you could have a catastrophic failure.

 

[sco44]

The specs I read state the pump is rated for 3-5 HP, so max rpm would be when using a 5 HP motor with the 9.5" drive sheave...using a smaller HP motor would require less RPM (lower gear ratio) in order for the motor to be able to 'pull' it.
It's no different than pulling a heavy load with a manual transmission in a gear too high for the engine to pull.
Another limiting factor is the maximum load the rods and crank were designed for. No different than increasing the compression ratio in your car engine. The pump parts are designed for a maximum load (PSI)...exceed this and you could have a catastrophic failure.

So this is how you would set it up, with a 9.5" pulley for 1000rpm? What is to gain by running 1000rpm vs 788rpm as it was stock? More cfm output?

I'm sure 20 cfm @ 120psi will be fine for the standard air tools i use.

Thanks for the help!

 

[md21722]

The specs are right there in the Grainger catalog. With a 5 HP motor, you should be using a 7-1/4" sheave and stop it at 120 PSI. Heat and load on both the pump & motor are limiting factors for both speed and pressure.

 

[The Tool Tyrant]

So this is how you would set it up, with a 9.5" pulley for 1000rpm? What is to gain by running 1000rpm vs 788rpm as it was stock? More cfm output?

I'm sure 20 cfm @ 120psi will be fine for the standard air tools i use.

Thanks for the help!

You stated 1000 RPM maximum...so I gave you sheave diameter for maximum.

As md21722 stated, the specs are all there. Go with the 7.25" for 758 RPM or 7.5" if you want 784 RPM.