Air compressor wiring question

[thejudges69]

Since I'm putting my shop up this year I'm in need of an air compressor. I was searching Craigslist and found an old champion compressor for 900.00. It's overkill for me but I felt the price was fair. My concerns are that it's 35+ years old. It was used to maintain a 9 bay work shop for truck repairs. It has not been used much in the last 15 years the seller said. Parts availability is a concern as well. And most important, its 3 phase, what would it take to convert to single phase? It's has a 7.5 hp baldor motor on it now. Would I have to change the motor? I don't have 3 phase at my property so whatever I buy has to be single phase.

I can get a new single cylinder 80 gallon 5hp for around 2k also a champion compressor. Should I just go new? This 120 gallon is over 4k new today.

I want the extra volume of a compressor and I need max psi of 175 for running bigger air tools. Just in case anyone was wondering.

Here is a link to the compressor
http://youngstown.craigslist.org/tls/5080410183.html

 

[94EG8]

Make sure you check the tank out thoroughly as they rust from the inside out. Tanks are not cheap. As far as the 3 phase goes, you'll either need a VFD or rotary phase converter.

I'd try hard to find a good used single phase 80 gallon 2 stage unit if you can before I jumped on this.

 

[930dreamer]

Good looking Champion compressor, do a search for 3 phase, three phase, there are some threads on this subject.

 

[bsaint]

Single to 3 phase VFD is going to be pricey. Probably more than a single phase 7.5hp motor.

Parts will always be easy to find for that unit as they still use the same casting, valves, etc... For 900 bucks it would still be a steal. Maybe even flip it.

 

[wyliesdiesels]

Is it possible to see it running before u buy it?

If u do buy it i would buy a single phase motor!

 

[sberry]

175 to air in truck tires too.

 

[PT Doc]

7.5 horse single phase motor will be hundreds almost for sure unless you call a motor shop and they have something laying around.

 

[LS6 Tommy]

7.5 horse single phase motor will be hundreds almost for sure unless you call a motor shop and they have something laying around.

Helluva a lot more than just "hundreds"...

Tommy

 

[Norcal]

You would need a 15 HP VFD derated 50% for 7.5 HP 3Ø motor w/ conductors being sized for 125% of the rated input of the drive, IMHO, keep looking for a smaller compressor, a 5 HP 2 stage w/ a single phase motor will do quite well.

 

[sberry]

Pass, there is a reason it is so cheap. As was mentioned look for a 5 hp and it is something I would really consider new. They last a long time and you don't start with someone else's problems as well as a project.

 

[BDT/NWMN]

About 20 years ago; I bought a new Sanborn 80 gal, 5 hp, two stage 175psi compressor and hardwired it in my downstairs utility room... Haven't had an ounce of trouble, and have powered 3/4" and 1" impacts and a sandblaster.... I doubt that your tale would be much different twenty years from now.

 

[thejudges69]

Thanks for the input. Originally I was gonna offer 600 for it and see what he said. The compressor is still.hooked up and I can see and hear it run. My concern was the tank, I can't really see the inside all that well. The compressor has always and still is in doors. They closed the shop and have since converted the building into store fronts. This is the only piece left of the shop. I don't think there are any noticeable problems with it but again I can't really see inside the tank. As for it being cheap, it is 35 years old and it is an estate sale. It was either the gentleman's father or father in law that owned it since new. The seller has used the unit himself growing up. It sounds like it's going to be pricey to change it to single phase though so I may continue to look for a single phase unit.

Question: if I could get it for around 6-700 would it be worth it? Pending a visual inspection and hearing it run of course. Maybe I could put my borescope inside the tank to look around.

 

[Norcal]

It is still going to be expensive to replace the motor or get a phase converter so you would be better off looking elsewhere.

 

[thejudges69]

It is still going to be expensive to replace the motor or get a phase converter so you would be better off looking elsewhere.

Ok. I think if I had 3 phase of jump on it. What would be a good single phase option? Single stave? 2 stave? I really don't know the difference.

 

[bsaint]

Does anyone know how much this compressor is new? Like 5x the price of a 7.5hp motor. Dont be paranoid about the tank. Dont listen to all these crazies who are talking crazy. Its an ASME tank. Its not rusted through. Did anyone reaize that the drain on these tanks is integral to the centrifugal unloader?

You know dont buy it. Ill go buy it, power wash it, and re sell it for at least twice the price.

Single phase baldor motor rated at 7.5hp is 650 dollars. Youre getting a hell of a compressor with a NEW motor in the end for 1500 bucks.

 

[sberry]

Just cause it seems cheap doesn't make it a good deal for everyone. There is a lot to be said for convenience. The op is a poster child for a mid range 5 hp 2 stage. He needs to air up truck tires and likely run a 3/4 impact on occasion.

 

[thejudges69]

I'm going to look at this compressor. I don't just air up truck tires and run a ¾" impact once in a while. I am going to look to see what he has going on. I know its overkill but when I need to run my sand blaster or multiple air tool at once or so on I'll have the compressor to do it with. I'd rather it be to big then not big enough or just big enough for once in a while. I don't know the difference between single and 2 stage compressors so I'm gonna figure that out tonight.

 

[sberry]

What I meant by once in a while is that while you are in the truck there is probably not going to be a multiple bay truck tire shop going on 24/7. A 5 hp will work, its a pretty fair amount of air. If I was planning on ramming multiple men you should be looking up to 7 1/2. The question is do we have 2 men airing hi pressure tires at once?
There becomes a point at which it is as practical to wait a minute.
If you remain a trucker the 5 will work, if you repair trucks you will need more but on single phase residential service there is a practical limit. Buy a nice 5 for now, shop for a project for additional. Flip the switch when you want to blast, parallel the tanks eventually if you want and the 5 will run everything you need the other 99.5 % of your life.

 

[sberry]

You do need 2 stage. A lot of the hobby crowd which you are not can slide by with 1, you can reman a car with a single. It however doesn't have the headroom for loss in transmission with large power tools where you need hoses. I mention truck tires in particular, a small comp puts out 135 at peak is going to take forever to fill some to 110, 175 in the tank even thru a reg at 140 works.

 

[sberry]

I could run my air out sandblasting if I really wanted to but I don't. I match it. It isn't worth additional investment to save a few minutes and most of the time it isn't worth even the time to hook the service truck air on.
I use 3hp on 200 gallons of tanks and can flip another 5 on but I don't need it. I am finished with most jobs before I am out of air. My use of large impact is very sporadic and the other exception would be blasting but a 5 hp will run a DA sander steady which is kind of a bench mark.
I have a heavy service but am on a long rural electric line and the ****** is modest. I like the 3 as mine is on 24/7 and it doesn't flicker the service. I have 3 hp well and 3 hp walk in cooler and they don't either but I can see a 5 if I pay attn., assume a 71/2 would be bumpier.

 

[sberry]

Buying something in working order and modest lets you use it now, nothing says down the road you cant fix er up. Don't starve yourself today.

 

[thejudges69]

Well, I thought I would chime in. I contacted champion direct, gave her the model and serial number and told her what I wanted to do. She sent me an email and I priced everything out to go to single phase and I have decided to pass on the unit for sure now.


see attached email below



Please see below from out tech services department. You can get the motor and starter quoted by calling your local distributor. Can you please provide your zip code first?



” This unit shipped in April 1977 & I definitely would be concerned about dumping money for this into a receiver that could fail at any moment. The only way to check if the tank is anywhere close to the proper thickness is to hope the tank data plate is readable to get the shell thicknesses & to contact a boiler inspector with the correct equipment to scan the tank & get measurements.

The tank does have a 200 # Pressure relief valve, but it could blow below that pressure & cause a lot of damage and / or death.



7.5 HP 230 v 1 ph motor P10397A

7.5 HP 230 v 1 ph starter CC1041269

Breaker size Minimum of a 50 amp breaker, but local codes must prevail

Wire size Minimum of # 6 wire, local codes must prevail.

A qualified electrician should be doing the re wiring & installation. “






Regards,



Customer Service Technician



Gardner Denver, Inc.

Industrials Group
1800 Gardner Expressway
Quincy, IL 62305

www.gardnerdenver.com

 

[wyliesdiesels]

U can use a 3 phase starter for a single phase motor. U just have to add a jumper from T2 to L3...

 

[engineer031]

I would not waste your time on a 35 year old compressor, even if it has been taken care of it will be in need of a rebuild. if you want it for single phase you will have to buy a phase converter or buy a single phase motor and a 7.5 HP is not cheap.
I would look at Eaton Compressors a friend bought one 3-4 years ago a 2 stage 5 HP it runs quiet and they are priced not that bad. They have a web site to compare

 

[thejudges69]

I would not waste your time on a 35 year old compressor, even if it has been taken care of it will be in need of a rebuild. if you want it for single phase you will have to buy a phase converter or buy a single phase motor and a 7.5 HP is not cheap.
I would look at Eaton Compressors a friend bought one 3-4 years ago a 2 stage 5 HP it runs quiet and they are priced not that bad. They have a web site to compare

Never heard of Eaton but they have great reviews from a quick look and are made right in Ohio. I'm gonna look into them.