compressor question

[HacksawsGarage]

okay, i went back and re read the "show us your....." thread completely through one more time.

and yet , i am more confused then ever on some terms i hear used here, and elsewhere.

whats the diference in these terms:

2 stage - means the air is compressed twice. that i got.
2 phase- whats this? same as above? or something to do with the wiring?
2 pole- is this the same as 2 phase?
1 pole- i know some compressors are wired this way, or 2pole. yet they both might be 220v? why would you choose one over the other?

i am still deciding on what compressor to buy.
my requirements/parameters are-
60gal vertical tank preffered(or less if practical) do to space restraints.
coming into the garage, i have 3conductor 10 w/ground 600v line.
intended for occassional use of air ratchet and cut off wheel and some small cabinet sandblasting of mc parts. of course tyre inflation. no painting.

alot of what i see most guys have in their garages here, appears to be overkill. then again, my little crappy 3.5 vibratory BlackMax is headed to the bone yard first chance i get to toss it outta here!

thanks in advance for any comments.

 

[flesburg]

Of the air tools you mentioned, the cut off wheel will **** the most air. Same with a die grinder, and air sanders...and a big sand blaster...

But that said, if you do not mind waiting for the compressor to catch up once in awhile, and do not want a big unit, I'd opt for a portable compressor. Go look at a Craftsman, piston compressor that you can change oil on (no oil-less, no ******** type) but a cast iron piston compressor. I have a 30 year old 3HP that I use for backup and keep in the attached garage for what you are describing. Want a good one? I have a 5hp (220v single phase) 80 gal Quincy 2 stage. ( Single phase 220 is what you have at your house, I do not have a clue as to what someone means by 2 pole or 1 pole...I thought that was only at fire houses, or at strip clubs)....

 

[Steve in Mi]

Depending on how long the run is on the 3conductor 10 w/ground feeder it can be a Good News/Bad News sorta deal.

Good News - the #10 wire can support a real 5 HP compressor (which should handle all you describe) .... but ..
Bad News - you may not have enough power to see (no lights) when that 5 HP starts up.

1 pole 2 pole may be referring to 1 and/or 2 pole breakers.

 

[Charles (in GA)]

There is single phase (regular house electricity, either 120V or 240V) and there is three phase (used in commercial and industrial applications, 208V and 480V mostly). Some people might call your 240V house current two phase, but it isn't. There really is no animal called two phase.

Two pole probably refers to the duplex type breaker used in 240V current. People get confused because there are two breakers ganged together, they think its different than the one breaker used for 120V, but both are current in one and current out the other) I know, it isn't DC but thats the best way to describe it.

One pole, or single pole, is the single breaker used on 120V circuits.

Charles

 

[Steve in Mi]

There really is no animal called two phase.Charles

FWIW, Read about 2 phase power here.
http://www.3phasepower.org/2phasesystems.htm

 

[6768rogues]

Motors are typically single phase or three phase. Three phase are more efficient and are self starting, because the phases rotate. In a residential setting, it is very uncommon to find 3 phase.
Your residential 220 is actually two 110 lines in phase with each other, hence, single phase. Three phase is 3 live wires, each 120 degrees out of phase with the other so their voltage does not add up the same. Using root mean square (learned in college many moons ago) three 277 volt lines in three phase add up to 480 volts. Cool stuff.

 

[Charles (in GA)]

FWIW, Read about 2 phase power here.
http://www.3phasepower.org/2phasesystems.htm

Thank you Steve, I did not know that. I stand corrected. There is an "animal" called two phase, its just that you will never encounter it in everyday use.

Charles

 

[HacksawsGarage]

wow! cool responses.

so let me ask this.
if in fact, a 3hp compressor with say a 30 gallon tank could be found (i will check out the craftsmen suggested) that would give me the air power i need for the small duration jobs i am talkiing about, then i am more than pleased for that to be the case.
so......
why is 240 better than 120? assuming of course that it is.
why is cast iron cylinders better than aluminum?

now i understand 2 phase. thanks. the history is really cool to read about. well, at least i understand what it is. or at least what it isnt!! LOL!

single vs double pole i am not so sure about. i mean, why would you use one or the other? i have the 3 wires plus ground at my breaker box at the house, and at my fuse box in the garage. but one of the 3 wires wire is not being utilized. meaning at present i have a single pole 120v service to the garage. which i assume can easily be changed by wiring up to the correct breakers. i want to do that, right?

i guess i have 2 issues here, and maybe they should be in separate threads. but i dont want to drag home a peice of equipment i cant use. thanks.

 

[plinker]

why is 240 better than 120? assuming of course that it is.
why is cast iron cylinders better than aluminum?

Depending on the motor 240v will run with half the amps 120v motor.

I.E. a motor wired for 120v will draw 15 amps the same motor wired for 240v will draw 7 amps or about half.

Cast iron will last longer than aluminum, I believe it takes heat & friction better.

 

[Kevin54]

if in fact, a 3hp compressor with say a 30 gallon tank could be found (i will check out the craftsmen suggested) that would give me the air power i need for the small duration jobs i am talkiing about, then i am more than pleased for that to be the case

No!!!! A 3 horse 30 gal. tank will not give you very much without cycling quite a number of times. Any job that requires using air needs a larger compressor. The size that you are talking is fine for blowing up a tire, running a brad nailer, blowing out the car, etc. An air powered cutoff wheel will eat up a lot of air. An impact wrench does not work well on a small compressor. You will find yourself loosening the lugnuts, then using the impact to save time. But if you want to do any larger projects that require air as in painting, bodywork, impact guns, air tools (Tim the Toolman sounds inserted here) you need a larger compressor. Even a 60 gal. single stage cycles too much for air tools. A larger 2 stage is needed for air tools and painting. A single stage that cycles builds up heat. And with heat comes moisture, and with moisture comes problems. A 2 stage compresses the air faster so it does not cycle so much and the larger the tank the more volume and less cycling. You can get a decent IR 2 stage for around $1000. Expect to pay $500-800 for a decent single stage 60 gal. For what you are talking (3 horse 30 gal) expect $200-400. But remember that if you buy small and then start aquiring air tools, paint guns, you will soon be looking at a larger compressor. You may want to look at places like Craigslist, etc. for a good used compressor and get more for your money. Just my $.02 on the subject.

Kevin

 

[Kirby]

Sounds like we have some experts here, and I am certainly not one, but...
I think Kevin is sorta right. I have been using a 3hp, 30 gal. Craftsman for years, and when my present garage project gets completed I will buy a 5hp, 60gal, 2 stage compressor of middle-of-the-road quality($800-1000) for the new garage/workshop for cars and woodworking and leave the smaller one in the main garage for tire filling and small jobs. I have used the 3hp one for all sorts of air tools and painting, but it is limited, particullarly with the cut-off wheel on the die grinder...my angle grinders are all electric; and he is right about its limits with an impact wrench. But it still boils down to your budget and what you are going to do in your garage/shop. If you are not going to use a blast cabinet, not paint concours, and have a Sawzall, then maybe you can go a little smaller. Anyway lots of good input on this site. Good luck, Kirby

 

[HacksawsGarage]

thanks Plinker.

kevin- i dont plan on painting. i only use a cutoff wheel, what are they? 3 inch? to trim a few odd ball motorcycle fenders or cut a bracket here and there. but i do understand what you say. the problem with craigs list and big compressors, of course, is getting them home. but thats a good idea and one i will check on.

i think an 80 gallon tank would crowd my space too much and i would spend more time waiting for it to fill on initial start up for some of the smaller things i do, than any time i spend waiting in between fill ups on bigger jobs. however, having impact gun capacity would be important now that i think of it. i am gomma check around craigs like you say.
i guess ya never know.

 

[cj7jeep81]

as long as you don't have any leaks at the compressor (in your fittings), you shouldn't have to wait for the initial fill up every time. if you have leaks though, the pressue will go down over a few days and drain the air tank.

i'd definately go with a bigger compressor as well. i had a single stage 60 gallon, and hated running the die grinder or cutoff with it. i could only run the tool for a short bit, then wait for the compressor to start back up. and if you're doing this for a business (and it appears you are), i would think you're time would be more valuable waiting for the compressor to catch up than a hobbiest like me.

also, can you take some pictures of your breaker panel? to feed a subpanel, you only need 3 wires (two hots and a ground), so if they used 4 wire, then yes, you would have any extra wire. however, you only use 3 wires for 120 circuits as well, so just because its only 3 wires doesn't necessarily means its 120. are there two wires going to the breaker in the panel (probably a black and a red or white) and a bare wire going to ground? if so, its 240v. if you have 1 black wire going to the breaker, and the white wire going to a bar and the bare going to a bar, its 120.

 

[HacksawsGarage]

google hasnt helped me find any vintage compressor people to research the models i find out there used for sale. anyone know of any on line old compressor experts?

 

[HacksawsGarage]

CJ- tha nks. i have to say i am not a bizz per say. i expanded my motorcycle hobby when i retired from construction engineering last year. i do build a bike now and then and am still selling off the ton of swap meet stuff i have aquired over the years. but i am not an actual retail bizz. actually i have pulled out of the commercial space i was leasing, and now back in my home garage. which is the reason for all my compressor woes.

i am not sure if 5hp and larger will be to large a draw. that seems to limit me considerably.