Air compressors: Single phase vs Three phase operation

[EW57]

Greetings, I'm considering purchasing a 5hp compressor with the option of single phase 230V or three phase 230V motor & I currently have both 230 single phase and three phase available (through a 20hp roto-phase converter), and was curious as to which would be more efficient in the long run. I was leaning towards the single phase unit as I'd rather not have the roto-phase on & idling for long periods to time, but wanted to get the opinion of those with a better understanding than myself. Thanks & take care.

 

[930dreamer]

I have a 5hp three phase compressor running off a 10hp rpc. If I'm using it for serious DA/sanding the rpc stays on (obviously). For most work I'll charge the tank and turn off the rpc.

Someday it's going outside. Because I have a test circuit for three phase and three floor model grinders it's easier then installing more 240v single phase outlets.

 

[kaffine]

If you have the option in that case I would go single phase. Unless the 3 phase setup is a lot cheaper. No sense in needing to run the phase converter to run the air compressor. Also nice to keep loads off the phase converter in case you get more 3 phase equipment and need the capacity. When I got my phase converter I figured 10HP would be enough now I am looking at upgrading. I currently have 12HP of motors that may run at the same time.

 

[EOC_Jason]

For just a 5HP compressor, I would go single phase for the same reasons others posted above.

 

[Charles (in GA)]

If you are buying a new compressor, and have a choice, its a no brainer to select the single phase. Even though it can be run off the RPC, it makes no sense to have to fire off the RPC and leave it running just to use compressed air during the time you are in the shop. And should you ever decide to upgrade compressors (say to a 7.5 hp) then you have something you just about cannot sell. About the only good thing about the three phase is the motor is slightly cheaper, but the magnetic starter is probably a little more costly.

Charles

 

[theoldwizard1]

Greetings, I'm considering purchasing a 5hp compressor with the option of single phase 230V or three phase 230V motor & I currently have both 230 single phase and three phase available (through a 20hp roto-phase converter), and was curious as to which would be more efficient in the long run. I was leaning towards the single phase unit as I'd rather not have the roto-phase on & idling for long periods to time, but wanted to get the opinion of those with a better understanding than myself. Thanks & take care.

Single phase if the only 3 phase you have is after a rpc. MUCH more efficient !

 

[EW57]

Thanks for the input everyone, single phase it is!

 

[PT Doc]

I'm not sure how the above posters feel, but I think I'd go with the single phase unit.

 

[pmason0]

If your buying new and have the budget I would probably get the single phase unit, gives you flexibility if you move. But if your looking used you can pick up a 3 phase cheaper. That is what I did, had 3 phase in the shop so found a 80gal 5hp 3 phase a lot cheaper used than the single phase versions.

 

[AndyA]

Single phase.... unless you catch a really really cheap three phase compressor (because no one else can power it). Even then I'd probably swap out the motor for a single phase.