Rotary Phase converter

[wantacoe]

I am getting ready to wire my shop. I have a 7.5 horse 3 phase air compressor. I am looking at this rotary phase converter. The compressor is 22.5 Amps as is. Once i add the converter will the amps stay the same? What size wire and breaker will I need for this? Thanks. https://www.ebay.com/itm/165315843916

 

[jar944]

I am getting ready to wire my shop. I have a 7.5 horse 3 phase air compressor. I am looking at this rotary phase converter. The compressor is 22.5 Amps as is. Once i add the converter will the amps stay the same? What size wire and breaker will I need for this? Thanks. https://www.ebay.com/itm/165315843916

You will likely need a 15hp converter to start the compressor, so plan for that as far as power requirements.

 

[wyliesdiesels]

The amps wont be the same

How large is the feeder going to your shop?

 

[wantacoe]

The amps wont be the same

How large is the feeder going to your shop?

Not sure but the electrician who did it said it is 400 amps.

 

[Walkers]

I have been running a phase converter for at least a decade and have built 2 of them for others. I have used them with many different types of equipment (saws, mill, lathe, 2 post lift). In my experience you will be far better served, on an air compressor, swapping out the motor. On compressors it is easy, there is lots of flexibility, just need a motor with a base that fits the grooves on the compressors base plate. Also, since a compressor is on and off a lot the PC has to run all the time. It may not be a huge deal power consumption wise have the PC running at 3 or 4 amps at idle all day long, but it gets annoying! Swapping the motors is probably cheaper up front as well. You can also look at the pumps speed and out put and adjust to your needs by putting in a 5 horse if you don’t really need the 7.5.

 

[Walkers]

Link for an IR motor for $375

INGERSOLL RAND 23172604 Motor 7.5 HP 1-Phase For 45465101 Compressor DAMAGE | eBay

Find many great new & used options and get the best deals for INGERSOLL RAND 23172604 Motor 7.5 HP 1-Phase For 45465101 Compressor DAMAGE at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[wantacoe]

I have been running a phase converter for at least a decade and have built 2 of them for others. I have used them with many different types of equipment (saws, mill, lathe, 2 post lift). In my experience you will be far better served, on an air compressor, swapping out the motor. On compressors it is easy, there is lots of flexibility, just need a motor with a base that fits the grooves on the compressors base plate. Also, since a compressor is on and off a lot the PC has to run all the time. It may not be a huge deal power consumption wise have the PC running at 3 or 4 amps at idle all day long, but it gets annoying! Swapping the motors is probably cheaper up front as well. You can also look at the pumps speed and out put and adjust to your needs by putting in a 5 horse if you don’t really need the 7.5.

That sounds like a good idea. This is the compressor I have.

 

[Walkers]

Nice. I had it in my mind it was a tank mounted compressor. You will likely have to buy a motor starter and pressure switch. That is likely set up for the motor to run continuously and just use an unloader to stop the compressing (pump still turns, the valves are basically open though). Also, depending on what they rating plate says, it is unlikely (not impossible though)that it was meant for 230 volt 3 phase, which is what you would have with a phase converter.
So, find your favorite flavor of motor, a storage tank, a pressure switch, a relief valve, and get to it.

 

[wyliesdiesels]

Way overkill for a small shop. The electricity usage will be enormous since its probably a continuously ran compressor

 

[sparky 1971]

I am getting ready to wire my shop. I have a 7.5 horse 3 phase air compressor. I am looking at this rotary phase converter. The compressor is 22.5 Amps as is. Once i add the converter will the amps stay the same? What size wire and breaker will I need for this? Thanks. https://www.ebay.com/itm/165315843916

I thought this thread looked familiar. Were you ever able to verify that the compressor even works?

I bought a Kaeser model AB 1000 air compressor. 7.5 hp, 3 phase. I was told that you can run a neutral wire to make it single phase. If true is that a permanent fix? If not is it ok just to test the compressor. I bought it at an auction "as is". I would like to know if it is any good before spending more money on it. Thanks for any info.

Just based on my experience with Kaesers that are mentioned in the above thread, I would cut my losses, try to sell what you have, and get something a little more user friendly and cost effective.

That sounds like a good idea. This is the compressor I have.

 

[Steve from Socal]

I agree with Wylie, a rotary is not great for intermitant/ low usage air demand. If you are running machines that require air they are ideal for shop air where you use it a couple minutes here and there no. For sand blasting with an additional tank they are great. I have a 5 hp 80 gallon piston compressor the is used 99.8% I have a biger rotary for heavy blasting.

These run all the time, the unloader does reduce the power when not needed but, the motor is not just freewheeling at no load. They don't like cycling on/off temp stabilization is a factor in lifespan. Hot/cold cycles are really hard on the compressors.

Steve

 

[wantacoe]

Sparky71, No, I have not checked it out yet. I have a 5 hp 80 gallon compressor I use in the shop. I was going to use this one for sandblasting. The 5 horse keeps up but it does have to run all the time for sandblasting.

 

[Steve from Socal]

With a rotary compressor a VFD would be a good option to run on single phase power. Soft starts on rotary compressors and VFD's are used now. These are different than piston compressors in their start profile. For sandblasting, continous use these are very efficient, the key is these need to come up to temp and run for hours. A 10 minute burst here and there is the hardest thing to subject a rotary compressor to, is your 'duty cycle' up to the merits of using the rotary. An extra tank for the 5 HP may even out the flow issues?

To sandblast a trailer frame the rotary would be great, to sandblast a few parts in a cabinet it would be a bad choice.

 

[mike93lx]

Sparky71, No, I have not checked it out yet. I have a 5 hp 80 gallon compressor I use in the shop. I was going to use this one for sandblasting. The 5 horse keeps up but it does have to run all the time for sandblasting.

Sounds like the 5hp is sized perfectly, as long as it is 100% duty cycle

 

[wantacoe]

With a rotary compressor a VFD would be a good option to run on single phase power. Soft starts on rotary compressors and VFD's are used now. These are different than piston compressors in their start profile. For sandblasting, continous use these are very efficient, the key is these need to come up to temp and run for hours. A 10 minute burst here and there is the hardest thing to subject a rotary compressor to, is your 'duty cycle' up to the merits of using the rotary. An extra tank for the 5 HP may even out the flow issues?

To sandblast a trailer frame the rotary would be great, to sandblast a few parts in a cabinet it would be a bad choice.

This is not a rotary compressor. It is a piston type with a divorced 125 gal tank.

 

[Firebrick43]

This is not a rotary compressor. It is a piston type with a divorced 125 gal tank.

I was about to say the same thing. I am baffled as to why they thought it was a rotary? The pictures show the compressor pretty clearly.

 

[Steve from Socal]

This is not a rotary compressor. It is a piston type with a divorced 125 gal tank.

I didn't see that until you mentioned it!

You could try a VFD with soft start to run this? I didn't look at the pics in detail and the little compressor on the case just looked like a blob!