air conditioner problem

[junkyardwarrior]

30x40x10 metal building.

I picked up a used (for one year, then removed from service and stored) package unit. 3.5 ton. Gas heat. Ruud RKNL unit. Not knowing and better to ask, I find out when I get home that it's 3 phase. Ugghh. It's a good unit-and clean. Problem is, I don't have 3 phase service here. All single phase and the poco doesn't want to run any 3ph out here since it's all residential service. I can't blame them, that and I really don't want to have 3ph run for one appliance.

Is there a reasonable way to convert 240v single phase to 208 3ph? Or would I be better off to **** up the loss and sell or trade it for a 240v unit?

 

[Rookie2]

sell it.

 

[acmikee]

is the indoor fan single phase or 3 phase. if its single phase then you could replace the compressor to a single phase and rewire as needed.

 

[Rockhead261]

30x40x10 metal building.

Is there a reasonable way to convert 240v single phase to 208 3ph?

No. It would be like trying to convert your V-8 to a V-6, and we're all aware that GM already tried that with the 4.3

 

[Falcon67]

There is - using a VFD - BUT a VFD has to control the motor directly. Thats not so much of an issue with a machine tool, it really would be in a AC unit. The second way to get get 3 phase would be a rotary phase converter. That would supply "real" 3 phase just like you'd get off a pole.

https://en.wikipedia.org/wiki/Rotary_phase_converter

Lots of DIY designs on the 'net. Whether any of that is a solution depends on how much a bargain the AC unit was LOL.

 

[bonneyman]

Sad to say, the only real options you have have been mentioned - convert comp to single phase (if you can) or sell the unit.
Too bad, because 3 phase compressors have the best torque and power and don't require capacitors to work. Never heard of a 3 phase comp locking up. They run or they blow - simple as that. But not every location has the 3 phase power.

 

[junkyardwarrior]

It was free. I didn't even have to leave the recliner. The guy just dropped it off at the house, it's 3 years old and then put up in storage when the building was demolished. I can put a little into it but honestly it looks like it may be of better use to someone else who has 3ph service, perhaps I can do some horse trading for a single phase split unit.

Appreciate the insight, as always. Love this site!

 

[Pathfinders]

That would be your best bet. Maybe Craigslist barter.

 

[LS6 Tommy]

Craigslist it. You would not only have to change the compressor, but you'd have to add start gear for it and possibly for the fans/blower, most likely have to change some of the contactors and maybe some relays. At the very least, you'd have to get a different control transformer.

Tommy