Air Compressor Help

[el Shanebo]

Hey guys. Kinda new here so I may be posting in the wrong spot. And yes I tried the search...Here's my dilemma. I have an 80 gallon Cambell upright compressor. Should be plenty of juice to run almost anything, right? Well, I have tried every configuration of fittings, regulators, water traps, etc. and I still can't get it right. It seems that the motor will fill up the tank to about 150 pounds but then as soon as I start running a 90psi sander, the motor kicks on and runs for a long time. Its like the stored air in the tank won't keep up with my tools. Especially sanders, grinders, etc. I am not 100% sure that the wiring was done correctly. Would this cause these symptoms? What I do know is that I am at my wits end and I do not know what I'm doing... Every shop I have worked at, the compressor was already hooked up and running multiple tools simultaneously with no problems. Now its my shop...and my problems... Please..HELP!!! thanks--Shane

 

[MXtras]

An 80 gallon tank should run a standard air tool for maybe 15-20+ seconds before the pump comes on - depending on where the lower pressure switch is set. If the lower limit is set to 145PSI (unlikely) then it would pop on immediately - it's doing it's job.

It is common for the compressor to run when you are using the stored air from the tank. I do not see this being a real problem unless it runs for 5 minutes to compensate for 1 minute of tool use.

The shops you worked at likely had large volume, high dollar compressors that were very capable of handling high volumes. The smaller compressors are not usually well suited for high volume.

What is the rated CFM output of the pump and how old is this compressor? WHat size motor?

Scott

 

[el Shanebo]

Mx, thanks for the quick reply. I am going to my shop tonight and I will get the info off the motor. I understand what you are saying about a large volume tank. But like you said, my compressor is running for 5 minutes for 1 minute of tool usage. Extremely annoying. The compressor is old but it came from a "working" mc shop in my town and I know that they used it daily for basically the same thing I am using it for. I was hoping to unplug it, move it to my shop, plug it in and go. That what leads me to believe that I have done something wrong. Thanks again--Shane

 

[CraigFL]

When you run the tool, watch the pressure upstream from the regulator and also downstream. Downstream should be a constant 90psi and upstream should be 150psi dropping slowly to the motor-on set point.

 

[SteveU]

Your compressor probably puts out somewhere in the 13-15 CFM range while the sanders, die grinders, & similar use around 20+ CFM so the compressor is not going to be able to keep up running them constantly. The air drill I have is an air hog so within 10-15 seconds of running will kick the compressor on & I have a 80 gal tank also. High consumption tools don't take long to deplete an air tank & after that if your compressor doesn't have enough CFM to keep up you will have to take a break to let it catch up or you will run out of air to the point the tool stops working. This is rated at 19.5 CFM and is about the minimum required to run a die grinder constantly without running out of air. Cheap air tools seem to be built to looser standards and use more air than the higher quality tools so going to higher quality tools can help if flow is marginal.

 

[W-Cummins]

Drain the tank until empty then turn off the air at the compressor and start the compressor, next record how long it takes to pump up to the shutoff pressure. Report these values ( time and max pressure) back here and I will give you the "Averaged CFM"* your compressor puts out**

This is also a good thing to do when you get a new compressor as you can use it as a reference as to the health of your machine over time...

*(the average over the 0-*** psi range as it fills up)

**( with some error not accounting for temperature change of the gas and your barometric pressure )

William...

 

[DHill]

My compressor is not as big as yours but it is a 60 gal. Ingersoll Rand and I had issues with the pressure switch. It malfunctioned right out of the box and let the pump run over max pressure. I pulled the plug and got a new switch, fixed the problem.

That Eaton compressor in the pic above is a nice machine.... if you need more capacity those guys sell individual pumps and motors for reasonable prices, so you can upgrade capacity if this problem persists for you.

http://www.eatoncompressor.com/page/page/518643.htm

Is your unit a lower RPM unit? 1750 rpm motor and 700 rpm pump, something like that? That's nice. Mine is a 3450 RPM and I think the pump goes at 1250 RPM. It's loud.

 

[SteveU]

Sounds like his compressor is operating the way it should, shutting off at 150 psi like it should just sounds like it is undersized for the application.

 

[johnny1290]

My 2 cents it sounds like its working normally. My cheap HF airtools are pigs and leak and use a ton of air. They're fine for what I do with them. Continual air grinder/sander/etc use? I may get 5 seconds before the compressor kicks on

 

[el Shanebo]

ok, guys. thanks for all your input. I had my Dad come by and check it out (electrical contractor/spray booth installer) He says its all hooked up right. I guess I'm just spoiled. Used to workin with much nicer equipment. I guess when you are on your own you gotta do it with what ya got. Thanks again for all the help...

 

[larry4406]

SteveU - off topic, but how do you like your Eaton? I am considering one from them.

 

[SteveU]

SteveU - off topic, but how do you like your Eaton? I am considering one from them.

I really like it, it will run a die grinder all day and never run out of air. The guy that installed my lift used a 3/4" CP impact to run the 1-3/8" fine thread nylocks down with that secure the arms to the carriage & it kept up with that alright. Quality seems good & both the pump & motor are a lot larger than anything you can find in a big box store. Matt Cain was willing to answer all my questions before I bought it, probably had him on the phone 20 min so the customer service is good. Haven't had any problem with it other than a weeping sight glass so just waited till I changed the oil to synthetic took it out & used a little pipe dope now no more leak. I've read everything I could find on multiple forums about them and haven't found anything negative so that's a good sign. Overall they are probably the best bang for the buck, to get something like a Quincy with similar specs you would be looking at 2000.00+ which wasn't in the budget at the time. For what I do being a 1 man hobby shop this is all I will ever need, if I ever needed more I could always swap in a 7.5 hp motor & different pulley & get 26 cfm out of it.