One more quick question (Air compressor)

[f575gtc]

Hello again

I have a question about my air compressor I bought. I was using my sand blasting cabinet today which calls for 10CFM @ 100PSI, and my air compressor had no issue producing air for it, but was not able to over come the sand blasting to shut back down.

The Air compressor is a single stage 5hp(22AMP) 60 gal, unknown SCFM but it says 23CFM in its documentation so I am assuming that is free air.

I have my pressure cut out at 125PSI, and the low pressure turn on at 105psi, once the compressor kicks back in, I can continue blasting and the compressor never falls under 100PSI, it is able to maintain around 105-110PSI while blasting, but the pump wont shut back off unless I take a 30 second break to build back up to 125psi.

I am assuming this is because its SCFM is too low over 100PSI, it feels like this pump is only rated for 13-15ish @ 90PSI. Is there any setting I can set the pressure switch to to help the air compressor stay off longer? Would using lets say a cut out of 125 psi and a cut in of 85-90PSI be easier on the pump? Or is the tank the weak link here and just too small?

Also if I need to run the pump continuously, how long is considered safe? Can I run non stop for 15 min without damage? The motor itself is rated for continuous duty, and the pump has full synthetic oil recently changed. The pump does get hot, but the motor is barely warm (the motor does have thermal overload protection on the magnetic starter) I have had no issues keeping the moister under control.

I do have plans to buy a better 5hp pump in the future single or 2 stage, but not until this one kicks the bucket.

 

[kams1973]

The only thing you'd be able to do is increase the pump RPM. Don't exceed the manufacturer's recommended maximum if you care about the life of the pump.

 

[f575gtc]

What type of damage on the higher side of the spectrum am I looking at if I let the pump run non stop for lets say 15-20 min? If the motor isn't cutting out I shouldn't be over working it. Other than the possibility of creating uncontrollable moister, can I seize out the pump?

 

[DekeT]

I was using my sand blasting cabinet today which calls for 10CFM @ 100PSI, and my air compressor had no issue producing air for it, but was not able to over come the sand blasting to shut back down.

, it is able to maintain around 105-110PSI while blasting, but the pump wont shut back off unless I take a 30 second break to build back up to 125psi.

Or is the tank the weak link here and just too small?

The simple answer to this is because you are using more than 10cfm at the cabinet. The cabinet specs mean you need a minimum of 10cfm for effectiveness, not that it will draw that exact amount. It's not like an electric appliance that will only draw enough current to operate. Your airline opening will allow as much air as the pump can push through the opening.

While the pressure is below the cut-off it will continue to run to the high pressure. Your pump is operating correctly.

Your tank size has nothing to do with the continuous free flow condition you are operating at.

 

[sberry]

I have a question about my air compressor I bought. I was using my sand blasting cabinet today which calls for 10CFM @ 100PSI, and my air compressor had no issue producing air for it, but was not able to over come the sand blasting to shut back down.

I see the post above me has it nailed.