Thee phase compressor what to do ?

[ACman 7,621]

Well my son brought this home as part of a trade . It was only used a backup compressor at a plastic injection molding company and he says it only has 50hrs. on it . They had to buy a bigger backup is the only reason why he ended up with this one . Problem is this is a three phase unit costing between $2000-$2500 . I’m putting my feelers out for a single phase motor as new ones are pricey and it looks like the converters are the same . He doesn’t have to do the trade so he’s not out anything but it would sure be a nice addition to the shop . So guys what’s your thoughts on this and what would you do ?  Any ideas much appreciated.

 

[BaySide1 138]

Easiest way would be to replace the motor with a 220VAC one.

Otherwise, it is a bit of work to manipulate this 3 phase motor to work with what you have.

[Ed Kennell 38,748]

Looks like a K-181 would bolt right on Jeff.    

[ol550 830]

Best way to avoid any problems on your part is to leave it on the pallet and ship it to me.  

[Aldon 4,827]

I would also suggest 220 motor.

 

 

[ACman 7,621]

I’ve been searching CL for a motor and I’m not the only one looking for single phase motor for there compressor . The guy also said he could go into his computer and pull up all the times this compressor was used and print me off a log . What you guys think it’s worth ?  

Edited November 22, 2017 by ACman

[953 nut 55,910]

Jeff, if a seven HP single phase motor is cost prohibitive check around for a smaller motor and change the drive pulley size to allow it to run the compressor at a slightly slower speed.

https://www.northerntool.com/shop/tools/product_200660731_200660731

[DougC 2,641]

Jeff. PM Mike. He can probably get a remanufactured single at wholesale ............

[Jerry77 1,218]

Well, it sure is worth buying a 5 or 6 hp single phase, 220 v motor for it....last a lifetime.. or like Ed said, put a gas motor on it..probably the cheapest way to go...

Or hey, look at this: https://www.ebay.com/p/6-4-HP-3450-RPM-Single-Phase-240v-56-Frame-Electric-Air-Compressor-Motor-7-8/2201446942?iid=281404873364  300 bucks with free shipping..    6.4 hp

[squonk 41,464]

4 hours ago, Ed Kennell said:

Looks like a K-181 would bolt right on Jeff.    

I'd go with an Onan twin or a big honkin Wisconsin! 

[ztnoo 2,298]

Well you don't mention what that actual value of the "trade" is.

Depending on that figure however, it would seem to moi sticking a new $200-$300 220/240V electric motor on it would make it a pretty reasonable deal.......IMO.

[ACman 7,621]

3 hours ago, ztnoo said:

Well you don't mention what that actual value of the "trade" is.

Depending on that figure however, it would seem to moi sticking a new $200-$300 220/240V electric motor on it would make it a pretty reasonable deal.......IMO.

 

So my son just told me it’s about 3-4hrs of work (siding) but he’s also supposed to give him my compressor which is a $400/450 2hp 30gal Kolbalt and is like new . This air compressor always trips the breaker when it starts for the first time . It’s plugged into a 20amp socket ran with 12-2 wire on a 20amp breaker . All my 20 amp circuits are this way on there own breaker and it doesn’t matter which one it’s plugged into . The only thing is the guy doesn’t know what I have so I could find another compressor off CL . This guy also got the Ingersoll from work for free (but no way to get it home) and he just wants a smaller compressor for his garage . My son wanted to do the trade because he’s always slow to pay .

 

Edited November 23, 2017 by ACman

[squonk 41,464]

Your circuit probably cannot handle the inrush current on the little compressor. Is there anything else on your outlets? Any room in your box too add a dedicated circuit? You would need a 220v circuit anyway for the big compressor with a new motor. Going to need some oomph to get that big pump spinning. Without knowing what your current (No pun) electrical situation is, to get a large enough motor to run that compressor the way it was designed to do, you would at least need a 40 A circuit and 8 ga. wiring. That's figuring off the top of my head. 

Edited November 23, 2017 by squonk

[Jerry77 1,218]

1 hour ago, squonk said:

to get a large enough motor to run that compressor the way it was designed to do, you would at least need a 40 A circuit and 8 ga. wiring.

Considering all that you would have to do: give up your compressor//additional electric service// and purchase a new motor....do you really need that big of a compressor?   sounds nice, but........

[squonk 41,464]

If you want to do a lot of sandblasting, Yes a big compressor. Otherwise update the shop wiring enough for the little one. Dedicated 30 A breaker and maybe 10 ga. wire depending on how long a run it has to be. 

[ztnoo 2,298]

I'm no electrician........wood was my game, but almost every powered electrical device is initially going to require more amperage on start up than to keep it running.

If your wire gauge and the breaker the current is running through isn't sized adequately, it's going to consistently trip the breaker.

If the breaker fails and freakishly leaves the circuit open, the wiring to it will get hot and eventually fail.......meaning the end result could be a fire and no building to house that compressor......or anything else, for that matter.

[Racinbob 11,251]

Jeff, I'm kinda feeling that the benefits of the big compressor may not be worth the $$. That's something only you can decide.

As far as the Kobalt compressor issue there's something else going on. Sure, there's a current spike on start up but it should not be tripping a dedicated 20 amp circuit. Heck, most people would plug it in to any ol recep in the garage and it would run fine. But I am a fan of adequate wiring for a tool with a current rating like that and I also ran a dedicated 20 amp circuit  to power my hungrier power tools. I don't have enough information to feel confident about an answer but with the little I have I'd be leaning towards something being wrong with the compressor. It absolutely  shouldn't be tripping a properly installed dedicated 20 amp circuit.

[Sarge 3,463]

Length of wire run and gauge are the two biggest factors . To run correctly , the power cord should be at least 12ga and pretty short - maybe 6' total . Inside the panel to the outlet - 12ga minimum as well . You could pop the breaker out or have an electrician check it - they can sometimes burn their contacts to the supply bar enough to not be able to supply full amperage . Same with the screw terminal - if it wasn't tightened properly during the install it can drop the current level available in a hurry . That IR T30 unit is a decent compressor but you'll need a 5hp minimum depending upon it's efficiency rating and age or a 7.5hp to run it on single phase . It will require being pretty close to the breaker panel and need at least a 50amp breaker to feed it on startup . I had to convert my old SpeedAir the same way and used a heavy farm duty capacitor start motor to power my big 2 stage - inrush it pulls around 62 amps and recently ate 2 of 3 of the starter caps - no big deal to replace them and an easy fix with some reading and advice from an electrician buddy . It's a lot nicer to have a fully capable twin stage continuous duty cycle compressor for doing heavier work - the day I blew the caps it had ran over 6hrs almost continuously feeding my sand blasting pot when I stripped the utility trailer . Probably just got the aged caps too hot on so many hot re-starts is the reason for the failure but all good now .

 

That little Kobalt unit would only be good for occasional light duty use - push it very hard and it will fail . I'm a huge fan of overkill - things just last a lot longer and the bigger unit with some care should last a lifetime of service .

 

Sarge

[ACman 7,621]

All my 20amp circuits are on there own . I did at least one on every wall to run the 120v mig welder without issues . Right now the little compressor is plugged into the 20amp outlet right below my panel so there’s maybe 3’ of 12-2 wire . It doesn’t matter what circuit it’s plugged into . The house and barn was built by a electrical contractor and all my other electrical is done by journeyman election friend . Everything is to code as I’m very picky on any trades work done on the property . I’m thinking that the big compressor won’t be sticking around  . The small one runs the air tools just fine and now my son has the Milwaukee cordless 1/2” impact (it’s ) for those rusty bolts. I’ll just have to figure out the problem as Bob suggested .

[Aldon 4,827]

I’d install a HF predator on it since you would only need occasionally for when high volume air is necessary.

 

Where I am, getting anything sandblasted costs an outright fortune.

 

Being self sufficient was necessary evil.

 

i will say that I really like having a large compressor in the shop. When doing sandblasting it’s critical. When I need smaller amounts of air, it’s nice not to have the pump cycling continuously.

[Sarge 3,463]

If it's capable of handling that 110v mig - the compressor should be fine as you say . I'd bet it's just the starter or a cap on the motor...there are some fairly easy tests you can research on the net . Glad to hear you have the proper wiring - so many fires are started by insufficient wiring work in shops and garages . That big one would really shine if you ever wanted to buy or ran across a blast cabinet - once you have that resource you'll never go back to farming out that work - mine gets ran a lot and not just on my projects as everyone I know brings stuff over to blast it clean . There are other resources around here to get that stuff done , but like Aldon said - it's not cheap .

 

Sarge

[ACman 7,621]

I know what you’re saying about self efficient . I hate paying for anything that I used to do for myself . Heck even the stuff I don’t have to pay for still drives me crazy . Thankfully I know enough people that can help me out no matter what problem arises.  

[squonk 41,464]

The 20 A circuit, anything else plugged in or drawing a few amps? If so, that would also account for the breaker trip. That Kolbalt is a cheaply made unit. We had a Speedaire at work that was the same thing. That crappy pressure switch may not be unloading the head after shutdown. Does it hiss after shutting off every time? I’ve seen many compressors with faulty unloaders trip breakers 

Edited November 23, 2017 by squonk

[ACman 7,621]

Nothing else plugged in . It does hiss right when it shuts down and that’s it . Sounds like every other one I’ve heard at shut down . 

[953 nut 55,910]

If the starting capacitor on the motor is marginal it could be the culprit. Remove the belt or coupling from the motor to the compressor and see if it trips.