1st post: Air compressor questions

[Banjorear]

OK, I've been using my 3 cly. Curtis-Toledo "Econo-Line" air compressor for some time now. It has a 30 gal. horizontal tank now and I've been thinking of converting it to a 60 gal. or 80 gal. vertical.

Here are my questions:

1) Compared to a newer compressor, the motor seems huge. It is a Gould 3 h.p. (17 amp) 230V motor. It runs at 1750 rpm. In my old house, it would cause the lights in the house to throb even though the garage had it's own seperate service. My new place, I will be running a subpanel off the box and don't want that to happen.

2) Are newer compressors more efficient? I'm not talking because of wear, but efficient in general? My head was rebuilt when I got it, but it just doesn't seem to put out a lot of CFM. Granted, it seems like the set-up was rigged up sometime for the piping looks on the small size for the unit.

3) Would it be worth it taking it to a compressor shop and have them go over it, add the tank, etc. or just get a new one? One rule is that it must be US made.

 

[dbonne]

Welcome to GJ!
You should get a bunch of good advice here!

 

[Steevo]

That motor and pump combination is far better than most sold today.
At 230v/17A, that is a "real" 3HP motor.
The pump model number can be researched to determine the CFM rating at various RPM.
It may be lower volume than you want/need, but is still a good quality pump.

 

[Banjorear]

OK, thanks. I'll pull some numbers and check out the specs on it. I guess my next job is to get a vertical tank for it and switch it over.

 

[1Garageman]

That is a kick *** motor on there. Instead of buying a new one, you might consider getting another tank to connect to it also.

 

[Banjorear]

Thanks. I really would like to save space so I'm really leaning toward a vertical tank. 60 or 80 gal.

So, does the motor need to be that big? Seems like a lot of juice to turn the pump. Funny, I was looking at the pump last night and it must have been balanced from the factory because the flywheel/fan has dimples drilled on one half of it's face.

Did a quick search and it seems like Curtis-Toledo is a quality compressor manufacturer.

 

[justsam]

Sounds like you suspect some modifications have been done to this compressor. Make sure the pulleys are sized properly for that motor and pump. Trying to turn the pump too fast can make the motor draw excessive current and modulate your lights.

Low CFM sounds like a different issue and undersized piping can certainly be a cause.

 

[larry_g]

What is your goal in adding a larger receiver (tank)? If your working hard and running the compressor a lot at the end of the day the work you get done has nothing to do with the tank size. If you really think you need more receiver capacity then you can add more in parallel with what you have, leaving the original system intact. If your going to plumb the shop then the second receiver can be physically anywhere in the line.

lg
no neat sig line

 

[Banjorear]

What is your goal in adding a larger receiver (tank)? If your working hard and running the compressor a lot at the end of the day the work you get done has nothing to do with the tank size. If you really think you need more receiver capacity then you can add more in parallel with what you have, leaving the original system intact. If your going to plumb the shop then the second receiver can be physically anywhere in the line.

lg
no neat sig line

Hhmmm, certainly something to think about. I do use a die grinder and drill a lot. It is having trouble keeping up with these tools; especially the die grinder.

I also want to free up some floor space by going with a vertical tank.

 

[sands35]

3 HP at 17 amps on 240 - that's a real 3hp.

Keep it until is seizes - which should be never if you change the oil.

What air delivery do you need for what you do? That should dictate the tank size you need.

 

[Banjorear]

Die grinder, drills, impacts, cut off wheels, small spray gun, and I would like add a sandblaster down the line.

 

[sands35]

Those are in the 10-15 cfm range. Does it cycle on/off when using tools or run constantly?

 

[Banjorear]

Those are in the 10-15 cfm range. Does it cycle on/off when using tools or run constantly?

Runs constantly with a die grinder or drill. It will take a few minutes after I stop using the tool to catch up.

It will run the tool while it is running, but it just doesn't seem right. My impact IR 1/2" doesn't seem to have that snap that you would expect from a impact gun.

That's what got me thinking about this.

 

[larry_g]

What air delivery do you need for what you do? That should dictate the tank size you need.

The above statement is wrong. Air delivery is determined by the motor/pump. If your now running out of air in 5 minutes and waiting 5 minutes for the pump to catch up going to a 2x size tank will only allow you a longer run/recharge, 10/10, cycle but at the end of the day you only have the working time that the pump provides.

lg
no neat sig line

 

[larry_g]

Runs constantly with a die grinder or drill. It will take a few minutes after I stop using the tool to catch up.

It will run the tool while it is running, but it just doesn't seem right. My impact IR 1/2" doesn't seem to have that snap that you would expect from a impact gun.

That's what got me thinking about this.

Operation as described above, tank size will make no difference to you. Once the pump kicks on and your never cut-off then the tank is just a large sized pipe between the pump and the tool. Bottom line is you need a pump capable of delivering more air.

lg
no neat sig line

 

[JamieK]

Post up a picture of the metal tag on the side of the pump. It should tell us all the important information. Then we can tell if the pumps putting out enough volume, or if you may have other problems. Unless the pump is made for high pressure, then a 3 cylinder should easliy operate about any tool.

 

[sands35]

The above statement is wrong. Air delivery is determined by the motor/pump. If your now running out of air in 5 minutes and waiting 5 minutes for the pump to catch up going to a 2x size tank will only allow you a longer run/recharge, 10/10, cycle but at the end of the day you only have the working time that the pump provides.

lg
no neat sig line

Not really. Looking at the pics, it's a plenty big pump, hence my actual use question and how the compressor actually operates.

Yes, duty cycle matters and yes, that's related to the size of the tank and the delivery capability of the pump. There are other ways around that with accumulators or just waiting or doing something else for a few minutes rather than re-tanking a perfectly useful compressor.

A bigger tank can get around a too small pump - if the wait isn't too inconvenient.

There is also the issue of funds. Sometimes, it's useful to find something else to do for a bit (as long as the tool isn't for making money). I'd bet that new tanks cost more than a used compressor.

There could also be something else wrong like the seals are worn.

As the OP stated, a compressor running 100% has a pump that is either too small or it's got a leak or bypass in it.

As already requested, the nameplate rating of the pump and some anecdotes on the line pressure would be useful.