digital phase converter for comrpessor?

[jasonc]

i just inherited a 5hp 80gal compressor from a old friend. during the compressor rebuild i noticed i needed a 3phase outlet and i only have a 1phase in my garage.

the compressor is also Reciprocating so i cant run a static phase converter so i narrowed it down to a digital phase converter.

http://www.americanrotary.com/phase-converters.html

do i just need a digital phase converter panel or do i need one of those rotor also?

 

[Possum]

American Rotary seems to be well respected. Call them and see what they say you need.

 

[EdT]

I bought a 5HP single phase 220v compressor motor at the store we all love to hate (HF) for around $100 straightup, no coupon or anything. It's worked fine for about five years or more of moderate hobby type use. This past summer it ran all day everyday while I was siding and trimming my new building. That may be a more cost effective option than a phase converter. Also, one less thing to breakdown. Sometimes Northern has them as well.

 

[1Garageman]

I bought a 5HP single phase 220v compressor motor at the store we all love to hate (HF) for around $100 straightup, no coupon or anything. It's worked fine for about five years or more of moderate hobby type use. This past summer it ran all day everyday while I was siding and trimming my new building. That may be a more cost effective option than a phase converter. Also, one less thing to breakdown. Sometimes Northern has them as well.

Damn that sounds like a nice deal for $100.
Tell me how quit is it???
My damn Sears motor I just about have to wear ear plugs sometimes!

 

[larry_g]

I believe that air compressors are a special case when it comes to phase converters. They are a high load start and run situation that is intermittent. I would highly recommend that you talk with the tech reps and hear what they have to say. I run a RPC and it works real well, but I would not put a compressor on my system. If I were you and the only 3-phase unit I had was a compressor I would sell the unit you have and get a good single phase compressor.


lg
no neat sig line

 

[A_Pmech]

5HP is well within the capacity of off-the-shelf single-phase to 3-phase VFD's.

 

[mrb]

5HP is well within the capacity of off-the-shelf single-phase to 3-phase VFD's.

but to start an air compressor? Dont those things pretty much pull LRA until they start spinning? Is a 5hp vfd going to be able to start a 5hp motor in a hard start application? I would think you would really need to oversize the vfd.

 

[A_Pmech]

but to start an air compressor? Dont those things pretty much pull LRA until they start spinning? Is a 5hp vfd going to be able to start a 5hp motor in a hard start application? I would think you would really need to oversize the vfd.

Sure it'll start it. With the newer sensorless vector drives, the motor can actually produce MORE starting torque on a VFD than it would across the line if the drive is set up for torque boosting.

Depends on the VFD manufacturer. Some manufacturers recommend oversizing and others don't. It pays to research the particular drive. I'm partial to Hitachi drives myself.

 

[oldgoaly]

Give these people a call http://www.factorymation.com/s.nl/sc.2/category.15366/.f
You won't be able to use a cheap VFD but a vector drive should be able to run it. With a rotary you oversize it do to the high starting amps. I have 1 rotary I built almost 20 yrs ago, have 7 VFD's running other equipment. The static one I bought lasted a year and a month, never again!

 

[mrb]

Sure it'll start it. With the newer sensorless vector drives, the motor can actually produce MORE starting torque on a VFD than it would across the line if the drive is set up for torque boosting.

Depends on the VFD manufacturer. Some manufacturers recommend oversizing and others don't. It pays to research the particular drive. I'm partial to Hitachi drives myself.

ah ok thanks (i dont know enough about these things)

 

[930dreamer]

I use a 10hp phase converter to start my 5 hp 3 phase compressor. Here's a picture of the 10 hp and 7.5 hp converters.