# Best Brand Rpc For 3hp Lathe



## Lornie McCullough (Apr 11, 2016)

I want to buy a reliable rotary phase converter for my 3 hp 3phase lathe. What brands or companies do you recommend?

Lornie


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## JimDawson (Apr 11, 2016)

I don't have any specific brand in mind, but this looks like a reasonable deal and it's pretty much local.

*3 phase converter American rotary - $360 (Salem ne)*
https://salem.craigslist.org/tls/5518335740.html

The other option of course is a VFD, and you get the advantage of variable speed and controlled braking.


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## mksj (Apr 12, 2016)

If looking for something factory direct or through eBay, but probably worth a call to the manufacturer to see what works best and recommended size for your needs:
Phase-Craft
http://www.ebay.com/itm/7-5-HP-ROTA...D-FOR-1700-1800-RPM-IDLER-MOTOR-/290838235911

American Rotary
https://www.americanrotary.com/product-comparison
http://www.ebay.com/itm/American-Ro...o-3-Three-PH-Heavy-Duty-CNC-USA-/370755610715

As Jim mentioned, a VFD works well for a single machine, and/or to add more functionality to your lathe. VFDs can also be run off of a RPC, but some are better than others. If going the VFD route, invest in a decent VFD that is sourced through the US. At least you get a warranty and some accountability if you have a problem.


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## Brain Coral (Apr 12, 2016)

I have an Elimia 5hp RPC that I've had for about 6 years now with no problems at all. IIRC, it cost me nearly $650.00 at the time with shipping costs, etc.

http://elimiaindustrial.com/Rotary Phase Converters.html

I recently purchased a 10hp RPC panel for less than $160.00 and added a 10hp motor that I had been given for free.

The one noted on Craigslist looks like a good deal to me.


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## Reeltor (Apr 12, 2016)

I purchased a RPC control box from WNY Supply in New York and found the motor locally.  I can't locate their webpage but found PhaseConverterUSA site that claims to be the on-line sale site for WNY as well as other manufacturers. 
http://phaseconverterusa.com/Standard-Series_c_27.html

On the left menu look for Rotary Converter Control Panels.  Unless you are going CNC go with the Standard Series for Rotary Phase Converter not the static phase converter.  5HP control box is $138 and free shipping.  Used 3-phase motors can be found for next to nothing.  I picked up a used 5hp 3-phase motor for $25 it's now on a friends RPC for his Logan Lathe.  If you know anyone in the HVAC field, commercial A/C compressor units are usually 3-phase, many times the motors are sold for scrap; you might get one for the asking (and pulling from a compressor box).
Mike


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## Lornie McCullough (Apr 13, 2016)

Thank you everyone for your help. Jim... I emailed the Salem guy through the CL email, and he has not replied. I read every comment in the build your own sticky, but I don't have any of the components (motor) or electronic experience so........

I think I am going to go with our 'local' Yamhill guy, Croman Converters.

Lornie


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## JimDawson (Apr 13, 2016)

Lornie McCullough said:


> I think I am going to go with our 'local' Yamhill guy, Croman Converters.



Let us know how that works out.  I need to purchase a RPC for an upcoming project.


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## Lornie McCullough (Apr 19, 2016)

I did buy a 10 hp RPC from Jamie at Croman Converters. Hi seems to be a nice young (compared to me) man building converters out of his home shop, and seems very knowledgeable. It has been wired up for 3 days now, and powers the lathe just fine.

I have a new question for you all: When do you turn off the RPC? Do you leave the RPC running even though the lathe use is intermittent? What length of time "not using the lathe" would cause you to turn the RPC off?

Lornie


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## Brain Coral (Apr 19, 2016)

I leave mine running even if the lathe or mill use might be intermittent, but I might shut it off if there was going to be a lull of 15 minutes or more.... mostly because of the noise.

Brian


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## Reeltor (Apr 20, 2016)

I do pretty much what Brian does, turn the RPC off if it's not needed for  15-20 minutes or if the noise gets to be too much.


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## vertcnc (Apr 20, 2016)

Why not use a VFD rated for 1 phase in and 3 Phase out.   This would give you a wider range of variable speed, braking, soft start.  Less power draw.


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## buffdan (Apr 20, 2016)

My Harrison lathe also has 3HP motor, and I had a 5HP RPC which ran fine unless I started the lathe up in the high  speed (no gear) range, then the RPC/Lathe motor "complained". So I went to a 7.5HP RPC using WNY panel and it works great starting/running in any speed range.
The panel looks to be made well.
Here is their ebay store link: http://stores.ebay.com/wny-supply-phase-converter?_trksid=p2047675.l2563

Dan


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## Lornie McCullough (Apr 20, 2016)

vertcnc said:


> Why not use a VFD rated for 1 phase in and 3 Phase out.



I do use a VFD to power a 1 hp 3 phase bandsaw such that I can slow it down to cut metal. The 10 hp RPC will be wired to a 3 phase distribution panel to also power a milling machine (arriving next month), and maybe a 5 hp table saw and perhaps some other new purchase I haven't thought of yet.  I can see the RPC offers lots of versatility.

But how long should I leave it running without drawing power from it?


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## coolidge (Apr 20, 2016)

When I researched RPC's it looked like quality and quality of design were all over the map as was pricing. I found it interesting that American Rotary was the only RPC approved by Haas for use with their CNC machines.


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## Reeltor (Apr 20, 2016)

Lornie McCullough said:


> I do use a VFD to power a 1 hp 3 phase bandsaw such that I can slow it down to cut metal. The 10 hp RPC will be wired to a 3 phase distribution panel to also power a milling machine (arriving next month), and maybe a 5 hp table saw and perhaps some other new purchase I haven't thought of yet.  I can see the RPC offers lots of versatility.
> 
> But how long should I leave it running without drawing power from it?



I don't think it matters too much.  I have had my 15hp RPC run for an hour or so without drawing power from it with no apparent problems.    
Now that you have your 10hp RPC you are not limited too much on what 3-phase machine you come across and have it follow you home.


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## Brain Coral (Apr 21, 2016)

When I was looking at buying a mill, I visited a shop with a Bridgeport powered by an RPC that was below the floor. You couldn't hear it run, whatsoever. He had a light hooked in with a switch, so that he would be reminded to turn out the light when he left the shop, which also turned off the RPC. I'm pretty sure that he left it running all the time.

Brian


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## Firestopper (Apr 21, 2016)

I run a 7.5hp idler motor with a Phasecraft panel ($200) and the unit is very quiet as she idles on. This same motor was purchased back in 2000 when I built my first RPC system. The motor was sourced at a local motor shop for $50.00. Apparently the owner had it rebuilt and never picked it up so they sold it to me for what they had in parts.  If your set on a RPC, then call Phasecraft and get  the parameters for a motor that will work well with his system. He also balances the legs based on the motor you have (capacitors).

A word of caution, I have also purchased a Phoenix converter ("turn key 7.5 hp") and it worked fine, but much too noisy. Many folks assume all RPC are noisy (many are) but if you follow the recommended parameters such as RPM, service factor etc and a good quality motor mounted on isolators, you can achieve a quiet RPC system.  The Howell Idler motor I'm running is all cast construction continuos duty. Since I had the motor, I called Phasecraft and he sold me the control panel custom tweaked for my motor parameters. After install, I was pleased to see all three legs are balanced +/- 3%.  I  operate nine different machines with no problems, two of the nine machines also utilize VFD's for more control but receive power from the RPC. My first RPC system cost me $800 in parts so I'm conferable recommending Phasecraft. 
I ran dedicated conduit with #8 wire to all machine locations including ceiling drops. The larger wire size allows me to extend the system if I acquire another machine without amperage drop. The entire system is on a dedicated 40 amp breaker.  I have ran the system for hours on end operating  differant machines and the motor only gets warm to the touch.


If you are only running a lathe or mill, I would highly recommend a VFD for each machine (Hitachi quality) for maximum benefits of control. If your planning on powering other 3ph fabrication machines such as iron worker, benders, cold saws etc, then a RPC would be most cost effective IMO.


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