Air Compressor Stages/Phases?

[mikegt4]

D45
The Chicago Craigslist is not a single cylinder pump, there are 2 pistons of equal size in there each pumping into the outlet to the tank which means that it is a single STAGE pump. This link shows how it looks inside.

http://www.mastertoolrepair.com/air-compressor-pump-parts-vt490000av-p-60726.html

The Racine Craigslist is also a single STAGE pump but each cylinder is separate similar to a Harley engine. The air filter on each cylinder shows that both intake air and send it to the tank.

I think that you may be confusing cylinder configuration with the number of compression stages. Think of your right hand picking up some snow and squeezing it into a snowball (1st stage). Then you use your start using left hand to compress it more into a denser snowball (2nd stage). Usually a 2 STAGE pump will have a large piston for the first STAGE and a smaller piston for the second STAGE as can be seen in the parts diagram below.

http://www.mastertoolrepair.com/air-compressor-pump-parts-ci050000pd-ci070000pd-p-17943.html


Like single STAGE pumps, 2 STAGE pumps can be found in different cylinder configurations, side by side or in a V. The V configured 2 STAGE pumps are easy to identify because their big/small cylinders are quite evident.


In this diagram you can see the difference in piston sizes. The large first STAGE piston sends it's output thru a finned tube to the intake of the smaller second STAGE piston to be compressed again before being sent to the tank.

http://www.mastertoolrepair.com/air-compressor-pump-parts-5z017b-p-53291.html

I hope this helps.

 

[CompressorPros.com]

There are plenty of single phase (Usually 208-230 Volt) 80 gallon compressors, even some 120 Gallon, but they certainly are not common. I do not know of many 80 gallon Single Stage compressors, but they are out there. Usually those looking for single stage compressors tend to be also looking for value and the smaller tanks cut down on cost, so pricing is typically less than a Two Stage. Most of your single stage units will have a max pressure around 130 psi, where a two stage will give you 175 psi.

 

[D45]

It does looks like the CH, Porter Cable, and the Kobalt are all same.........and all have the same specs

They look nice for the price!

 

[D45]

http://www.northerntool.com/shop/tools/product_200455341_200455341

Puma Belt-Drive Stationary Vertical Air Compressor
60-Gallon Vertical
Model# PK6060V

$499.99 right now, on sale.....this is $700 everywhere else

2 Cylinder Pump

CFM at 90 PSI 12
CFM at 40 PSI 13.5
15 AMP
Max PSI: 150

 

[larry_g]

It does looks like the CH, Porter Cable, and the Kobalt are all same.........and all have the same specs

They look nice for the price!

That is why so many times I answer these questions with " Go with a color you like". So many tools are fron the same manufacture and made for mass marketing. The sellers order them in their color and maybe some other small detail change and the consumer worries about the best deal.

lg
no neat sig line

 

[MN Falcon]

My Older Husky says that it was made by Campell Hausfeld. I looked at a newer one the other day at HD because I was looking at a used one for parts and I thought the guy was a little crazy with his price for a non-op used one. The new one at HD looked like it was all offshore components. Not sure that it was made by CH, didn't see anything readily to show that, but still might be.

 

[2oolhound]

One other confusing issue with new compressors is the HP rating. It used to be a 5HP motor always sustained 5 HP but the new ones may only sustain 3.7 HP or so but can produce 5 HP at start up only. If the compressor motor is of the latter type there will be a couple of letters after the HP designation stamped on the plate. I can't remember off hand what those letters are, maybe someone can chime in so you can tell what the real HP of your motor is. Industrial compressors will have the actual 5 HP motors while the home owner types have the newer 5 HP with the letter designation suffix.

 

[CoopVA]

One other confusing issue with new compressors is the HP rating. It used to be a 5HP motor always sustained 5 HP but the new ones may only sustain 3.7 HP or so but can produce 5 HP at start up only. If the compressor motor is of the latter type there will be a couple of letters after the HP designation stamped on the plate. I can't remember off hand what those letters are, maybe someone can chime in so you can tell what the real HP of your motor is. Industrial compressors will have the actual 5 HP motors while the home owner types have the newer 5 HP with the letter designation suffix.

Generally, if the compressor can be plugged into a normal household 120v 20a outlet, then it is actually running less than 3hp. My compressor says it's a 5hp compressor on the label (not the motor data plate...) yet it can be plugged into a standard outlet. If it truly was a 5hp motor, on a 120v single phase circuit, you would need to put it on a 60a circuit... I'd have to take the cover apart to get to the motor, bit I'd bet money it's not a 5hp motor per the data plate.

Not sure were the compressor manufacturer gets the higher rating from, but I think it's locked rotor current...


Sent from my iPad using Tapatalk

 

[MN Falcon]

One other confusing issue with new compressors is the HP rating. It used to be a 5HP motor always sustained 5 HP but the new ones may only sustain 3.7 HP or so but can produce 5 HP at start up only. If the compressor motor is of the latter type there will be a couple of letters after the HP designation stamped on the plate. I can't remember off hand what those letters are, maybe someone can chime in so you can tell what the real HP of your motor is. Industrial compressors will have the actual 5 HP motors while the home owner types have the newer 5 HP with the letter designation suffix.

My older Husky actually doesn't have a HP rating on the motor. I think it says somewhere 5HP on the compressor itself. The motor rating is "SPL" and is rated at 15 Amp 220V . The Campbell Hausfeld that I got from my uncle is from the 1980s and it also says it is 5HP but the motor has "5SPL" rating and is rated at 15 Amp 220V. Like you say the newer compressors are rated at about 3.5HP 15 Amps at 220V.

I think they are required to start being more accurate with HP ratings because so many are so over rated. Leeson has a replacement, that they still like to use the 5HP in the information, "Specially designed as a replacement motor for air compressors, this motor has a high breakdown torque of a 5HP motor, but continuous duty rating of a 3HP motor."
http://www.northerntool.com/shop/tools/product_200306767_200306767

But I also wonder if you can easily say that any 3HP compressor rated motor would be a direct replacement because all compressor rated motors are supposed to be high torque start up motors.
http://www.northerntool.com/shop/tools/product_200596342_200596342

My original motor fried a wire in the start windings. It does have a second set of windings with a centripetal switch so I could see how they might rate the peak power at 5HP. The guy that took it apart didn't give me all the parts to put it back together, but I was considering fixing the motor with a jumper wire. My uncle's motor also will not start up, if I give it a spin it will sometimes kick in even after replacing the start capacitor. So I assume it has the same issue.

 

[wild cowboy]

$499 is my limit before I start requiring serious important features, first and foremost are a 1725-1755 RPM motor and low pump rpm <750 for long life and quiet operation.

Large tank size and/or two stage is not necessary for the home DIY guy unless you are doing body work or painting, which are the two high volume areas for most folks not in a large shop.

 

[KinzeMech]

I get the low pump rpm thing, as fast pumps tend to be loud, hot, and less volumetrically efficient, but for what reason does the motor rpm matter?

 

[wild cowboy]

I get the low pump rpm thing, as fast pumps tend to be loud, hot, and less volumetrically efficient, but for what reason does the motor rpm matter?

pretty much the same reasons on the motor

low motor rpm generates less heat and that yields very long motor life would be reason #1

noise would be reason #2

electrical efficiency would be reason #3

 

[larry_g]

I get the low pump rpm thing, as fast pumps tend to be loud, hot, and less volumetrically efficient, but for what reason does the motor rpm matter?

hp = torque x speed (simplified). The slower motors have a higher torque which is a bit better matched to the power curve of the pump.

lg
no neat sig line

 

[trboxman]

The Belaire is $699

http://www.aircompressorsdirect.com/BelAire-2061V-Air-Compressor/p4786.html


CFM @ 40 PSI: 8.3
CFM @ 90 PSI: 7.1

MAX PSI: 130
20 AM
2HP

Oil lubricated

Does not seem as powerful as the $499 Kobalt

The $799 5hp 60gal compressor at HF is made by BelAire. The pump is an IBAC made in Italy and the tank is made in the USA. No way I'd pay $699 for a 2hp compressor...

 

[JoelR]

all else being equal, the two cylinder (likely 2 stage) would be preferred for heavier duty needs, but Puma is the sleaziest Chinese junk out there, so be careful on that. I would put them on par with Harbor Freight, you need the extended warranty - lol

Puma's large compressors are made in the USA so...

 

[wild cowboy]

Puma's large compressors are made in the USA so...

they are assembled in USA, out of low bid stuff from worldwide, no better than HF

 

[JoelR]

the are assembled in USA, out of low bid stuff from worldwide, no better than HF

OK, where is that info from? Mine has a US made Emerson motor, A US made and ASME tested tank, Even has a US made Baldor pulley on the pump and motor. Thats a lot of US components. The actual pump i believe is Taiwanese out of an ISO 9001 factory...leaps and bounds above "cheap chinese junk". Hell, theres a lot of US factories that struggle to meet ISO 9001

 

[wild cowboy]

OK, where is that info from? Mine has a US made Emerson motor, A US made and ASME tested tank, Even has a US made Baldor pulley on the pump and motor. Thats a lot of US components. The actual pump i believe is Taiwanese out of an ISO 9001 factory...leaps and bounds above "cheap chinese junk". Hell, theres a lot of US factories that struggle to meet ISO 9001

which model is that, it's certainly not the $499 model we have been discussing in this thread!

and how old is it?

 

[JoelR]

Same model as discussed, got it 2 years ago for 400 on sale

 

[JoelR]

I should point out I think they are loose with motor manufacturers, I did see multiple brands represented on that aspect and chose the one with the Emerson

 

[wild cowboy]

as far as ASME certified, I didn't think it was legal to sell any compressor that does not have an ASME certified tank, so not sure that is a feature!

I will say that it is the lowest price I have ever seen for a two-stage, but where are they cutting the corners when a good two stage is $2,000?

If it is all Taiwan & USA components, I am cool with that, but the ones I have seen from Puma were not.

 

[JoelR]

If you look at HF page of that compressor you can compare customer photos with the stock photo and see the motors are different, as is the tank. The customer photo is like mine with the Emerson motor and US tank. Stock photo looks to be a different story

 

[JoelR]

I will say that it is the lowest price I have ever seen for a two-stage, but where are they cutting the corners when a good two stage is $2,000?

Its a twin split cylinder, but its only single stage. Actually thats part of what attracted me to that compressor vs a kobalt or similar compressor..the split cylinder gives more surface area for heat to escape...bonus for longevity. Dont get me wrong...I would love a nicer, more powerful compressor thats 100% US made. But its just not in the funds

 

[wild cowboy]

Its a twin split cylinder, but its only single stage. Actually thats part of what attracted me to that compressor vs a kobalt or similar compressor..the split cylinder gives more surface area for heat to escape...bonus for longevity. Dont get me wrong...I would love a nicer, more powerful compressor thats 100% US made. But its just not in the funds

well it sounds like a deal for the money, and you were smart to go through the motors and to think about the split cylinder design and end up with all USA and Taiwan, so you done well

the other question I would have for all of you all considering this compressor and the others in its price range is, what are the warranties on all of these?

 

[MacMcMacmac]

OK, where is that info from? Mine has a US made Emerson motor, A US made and ASME tested tank, Even has a US made Baldor pulley on the pump and motor. Thats a lot of US components. The actual pump i believe is Taiwanese out of an ISO 9001 factory...leaps and bounds above "cheap chinese junk". Hell, theres a lot of US factories that struggle to meet ISO 9001

Puma uses Swan pumps, made in mainland China. They are actually not a bad pump really. I'd take them over a lot of cheap ABAC, Balma and IMC pumps.

 

[rancherbill]

The guy who said only use compressor oil is right, and for the reason he stated. Motor oil is the worst thing to put in a compressor.

What is missing from all these discussions are 2 critical criteria.

The criteria are duty cycle and expected life.

You can take a cheapie like the Lowes one and try to do do sandblasting and it will die in a very short time. They are not built to run continuously.

The second thing is the expected life of the Lowes might be 1000 hours run time the IR are probably 2000 hours for their low end model.

The average home guy has all their need fulfilled with a smaller compressor unless they want to sandblast or get a plasma table. Both those applications have a lot of run time and a better compressor can handle the duty cycle.