Set up RPC

[G-ManBart]

I've been running my mill off a VFD, and it's been fine, but I recently bought a surface grinder, another lathe, and I'm keeping my eye out for a nice 20" drill press and a shaper, so it made sense to just get a rotary phase converter rather than keep buying VFD after VFD. After some research I went with the North American PL-7. I've only run the mill with it so far, but it seems perfect.

The picture will probably have folks asking what the heck my electrical panel setup is. Long story short, our power company needed a right-of-way to move their poles, so I got them to agree to run 3-phase to the pole they were installing next to my shop. I still have to pay to get them to drop a 3-phase transformer and pull the wire, but it's not a ridiculous amount, and I know it will be a huge asset when we retire and move back out West. That's why there's a trough in the picture...eventually I'll have two panels.

The RPC is only in place temporarily so I set up an outlet and have a 25ft extension cord that can get to the machines. When I have more time I'm going to run the output to the ceiling and have drops at each machine.

 

[projectnut]

With a converter of that size I'm assuming you'll only be running one machine at a time. I purchased a10 hp American Rotary converter several years ago and have yet to install it. I originally started with a single 3 phase machine and have added several others over the years. I found as I kept adding machines I needed to rearrange their locations. I'm now up to half a dozen machines that can run on 3 phase and am looking for a couple more. With each rearrangement of the shop I would have had to move and add 3 phase outlets.

Still not being settled with the final tool count and arrangement I decided to go with static converters on each machine as a 'temporary" solution. I was buying American Rotary static converters up until a couple years ago when they stopped making them. I tried on several occasions to find more American Rotary converters, but when they decided to discontinue them they sold off the remaining stock at ridiculously low prices. I was able to buy the last two 3 hp models brand new in the box for around $50.00 each.

The last machine I purchased ended up with a North America static converter. I didn't realize it at the time, but American Rotary bought out North America. Now when looking for a static converter American Rotary refers customers to the North America brand. Both companies seem to make many different quality products. American Rotary seems more geared to the larger commercial and industrial applications in that they offer units able to power up to 300 hp. North America on the other hand seems to top out about 50 hp.

 

[G-ManBart]

With a converter of that size I'm assuming you'll only be running one machine at a time. I purchased a10 hp American Rotary converter several years ago and have yet to install it. I originally started with a single 3 phase machine and have added several others over the years. I found as I kept adding machines I needed to rearrange their locations. I'm now up to half a dozen machines that can run on 3 phase and am looking for a couple more. With each rearrangement of the shop I would have had to move and add 3 phase outlets.

Still not being settled with the final tool count and arrangement I decided to go with static converters on each machine as a 'temporary" solution. I was buying American Rotary static converters up until a couple years ago when they stopped making them. I tried on several occasions to find more American Rotary converters, but when they decided to discontinue them they sold off the remaining stock at ridiculously low prices. I was able to buy the last two 3 hp models brand new in the box for around $50.00 each.

The last machine I purchased ended up with a North America static converter. I didn't realize it at the time, but American Rotary bought out North America. Now when looking for a static converter American Rotary refers customers to the North America brand. Both companies seem to make many different quality products. American Rotary seems more geared to the larger commercial and industrial applications in that they offer units able to power up to 300 hp. North America on the other hand seems to top out about 50 hp.

Interesting stuff about the two companies. I looked at both North American and American Rotary and the two were very similar...and the first couple of times I got confused which company I was looking at. I thought it was a coincidence, but now it makes sense why they look so much alike! One time I was on AR's site looking for the 7.5hp model and it wasn't there...that's because they don't offer one, which NA does.

I only plan on running one machine at a time, but in theory I could run two of the lower HP machines at the same time and be fine...my mill is 2hp, and my SG is 1.5hp as an example. I mostly went with the 7.5hp because a few machines I'm looking are easy starting 5hp loads this RPC should handle just fine. If I go beyond that it will probably be time to bite the bullet and have the power company drop a 3-phase transformer and add 3-phase power to my shop...probably have to remodel a room in the house for my wife before that happens

 

[slodat]

I have several three phase motors on VFDs with single phase supply - 7.5hp mill spindle, disc sander, drill press, paint booth exhaust fan and so on. I recently bought a 15HP American Pacemaker lathe. I had a 20HP American Rotary RPC sitting in my storage that I got in trade. I wired it up temporarily to see how it handled the big lathe motor. It went really well. Now I’m in the process of installing the RPC. I just installed the idler in a different room in my shop from my lathe I hopes I won’t hear the idler when it’s running. I’m installing a 3 phase panel that will be supplied from the RPC.

We don’t have natural gas here so I run quite a bit of electric heat (22kw). We have very low electric rates ($0.04/kWh) so it’s not terribly expensive. Well.. I’m running out of power with the heat running. At some point I may pay to have three phase ran to the building. My thought is I can feed my single and three phase panels from the outside of the building through the wall should I ever do that. And simply remove the RPC.

Why am I saying all this? You may want to think about installing a three phase pane on the output of your converter.

This is the panel I’m using. Plenty of spaces for circuits. I think I paid about $200 on eBay for the panel and cover. The breakers aren’t too expensive.