As most of you know I love the old machines. In fact my entire shop is vintage. The table saw is a 1952 Oliver 232, jointer a 1925-28 Crescent 8”, drill press is 1977 Powermatic 1150A, planer 1958 Delta 13” 22-101 and a 1968 Delta 14” bandsaw. All but the bandsaw and jointer are 3 phase machines. I would like to have a larger bandsaw some day and have my eyes open for a nice Tannewitz 30” that would fit the bill really nicely. But for now the 14” will have to do.
I have been running the 3 phase machines utilizing VFD’s, and while they do a fine job of converting single phase to 3 phase I was getting tired of shelling out $100-200 dollars every time I got a new machine. So, I decided to take the plunge and install a rotary phase converter. I will however, keep the drill press running with the VFD. Variable speed is just so nice to have with it and not having to swap belt locations on the sheaves is a time saver.
My quest for the RPC began about 3 years ago. I found a nice old cast iron Westinghouse 10hp 3 phase motor that could use as an idler to generate the 3rd phase. Best part of it it was only $60. Its solid cast with about 60# of copper in it, total weight pushing 130#.
I did pull the sprocket from the shaft and tore into the motor. It was full of dirt, spider webs, yellow jacket nests and appeared to have been in a flood. The stator was lightly rusted but the windings all looked to be in good shape. So, I ordered bearings and cleaned it up a little. About $20 for sealed Nachi bearings.
After some conversations with others who have RPC’s and LJ’s own TopamaxSurvivor, I decided that the new converter would require a 60A service. Luckily when I had the house built I had the foresight to upgrade the main service panel to 200A, it gave me enough room to add another 60A breaker. All that was left now was to start acquiring the necessary supplies to install it.
There are a couple of different options when it comes to installing a converter of this size. 1) you can purchase a ready made unit or 2) build your own. I chose not to build my own as my electrical knowledge is just enough to be dangerous and I did not feel comfortable with the construction and it would actually cost more to build. What I finally decided on was a pre-manufactured panel from American Rotary. They can be found here. However I must warn you, the panel only is not available directly from the their website. I found this to be a little odd and called to ask why. Their response was they have better sales on Ebay. So, I patiently waited for the one I had chosen to go on sale, which it did about 3 days later, and rest we shall say is history.
What I selected is a 10hp panel that is CNC ready. I will not really be needing the CNC balance capability of the converter but hey it was on sale and as I told the LOML, it was on sale and I saved you money.
I took a few days while waiting for parts to arrive for the Delta planer I am restoring went about installing the RPC. I started by pulling a few things off the wall where it would be located and removing a 1/2 sheet of drywall. The main service panel for the house is located on the same wall as the new RPC will be and only about 6’ away. It made pulling wire much easier and cheaper as well. 4ga wire is NOT cheap, nor easy to pull. I got the wire pulled and replaced the drywall. I did not want to use the breaker that I would be installing as a switch to power the panel so I purchased a 60A 2 pole 240V disconnect and ran the wire from the main into the disconnect.
Next was to mount the RPC panel itself. I had decided that I wanted it mounted fairly high on the wall to keep smaller hands away. With the panel mounted I went about wiring it. 4ga wire in 1” conduit is tight but doable.
With the majority of the wiring done I tunred my attention back to the motor and its placement. I wanted to place it in a location that would protect the rotating shaft. I built a small stand to get it up off the floor and tucked it back in between the wall and the garage door with the shaft in the corner.
Once the motor was mounted I set to wiring it. 10ga wire from the panel to motor in some water tight conduit and 30 minutes later I was cleaning up. Now came the time to fire it up and see how I did. Luckily my neighbor is a retired batallion chief with the local county fire dept if all went to hell I knew where to run..LOL
I went outside and turned on the main breaker feeding the disconnect, no tripping, arcing or humming….cool. Now inside to the disconnect, I threw the handle up and same result. I am at this point keeping my fingers crossed that the panel will start the motor and my efforts will have paid off. I hesitantly pushed the start switch and the idler sprung to life!! Very cool! The small stand does add to the noise of the motor a little. Kinda like a bass reflex speaker. Even though it is only 6” off the floor is does amplify the noise somewhat, but not so loud that you cannot stand next to it while its running and hod a normal conversation. But loud enough that I will never forget to turn if off at the end of the day.
All that is left is to install an outlet on the wall so I can now plug in my 3phase machines. It is not the best looking installation cosmetically speaking but it will get the job done. The motor I chose for the idler needs room to ventilate for cooling. It is an open design with no fan for cooling. I will be adding a piece of metal screening over the shaft to keep small scraps and hands away from it while its running. But for the most part its up and running. I also need to measure the balance between the legs and see how well balanced they are. I am also considering adding some small digital meters on the panel face that will read out the voltage of each individual leg.
I am now capable of running up to 7.5hp of 3 phase equipment and looking forward to getting it all finished. For those thinking it will cost an arm and leg for something like this I am here to tell you its really not too bad. The panel was $350 with free shipping. Bearings under $20. Wire, the expensive parts, was about $100. I do still have to mount the outlet which will cost about another $100-150. I know that seems high but it will also require rewiring each machine with a mag starter, power cord and plug.
Here is short video of not so good quality, but you get the picture.
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