Phase converter

[mriplaybass]

I don't know if he still has it. He was selling all of his machinery preparing to move to another part of the state, and when I asked him if he would sell it, he told me that he still needed it to demonstrate his remaining machinery to perspective buyers. He told me that he had picked it up used on eBay for $20.

 

[matthewsx]

They're fairly cheap new.

John

 

[Twirpunky]

I am a fan of the RPC. I know there are lots of good options with the VFD, like speed changes, but you need one for each piece of 3-phase equipment you end up with. A good RPC can be wired into a sub panel and you can wire the entire shop for 3-phase off one unit. The other advantage, at least for me, is that you just plug in your three phase equipment and run it. Nothing to rewire, or bypass or program. You get full power. All the control circuits and switches work like it came from the factory. If you have other motors on your equipment like coolant pumps they do not need to be changed out. Old three phase motors are cheap and can be wired to a phase converter panel. Several companies sell just panels.

 

[projectnut]

There are a number of manufacturers out there pumping out low quality static phase converters. Before purchasing one I would check the reviews on the manufacturer and model you're interested in.

I have 3 different brands in my shop. The oldest and most used is a Phase-A-Matic PAM 300 HD. It's been in use over 20 years and still going strong. At the time I bought it they were about the only ones on the market. They are good quality, but probably the most expensive of the bunch.

I also have 2 machines running on American Rotary brand static converters. I would compare these converters to the Phase-A-Matic, but they were considerably less expensive. Both machines are used regularly and have had them for about 7 years. Unfortunately about 3 or 4 years ago American Rotary discontinued making static converters They now offer a line made by a subsidiary North America Phase Converters.

I do have 1 machine running on a small North America converter. It runs well, but only gets intermittent use. It happens to be on a drill grinder that gets used only a couple hours a month. The grinder is mobile and moved around in the shop. The enclosure is made of a thinner grade sheet metal than any of the other converters. I have to be careful not to bump into things as I don't believe it could withstand much abuse.

Static converters are by far the easiest to install. In all cases for my machines it took longer to decide where to mount it than it did to actually mount it and wire it up. While I could have used a VFD on any of the machines 2 of the 4 already had built in speed and reversing controls that would have had to been rewired through the VFD. I liked the original control panel configuration and locations. Installing a VFD would have put the controls in a much less desirable position.

About the only machine I seriously considered a VFD for is the power hacksaw. It currently has 2 speeds (70 and 100 strokes per minute) accomplished by changing the position of the belt. The speeds are fine for most materials, but a little fast for Inconel and some tool steels. The next model up in the lineup had a 4 speed transmission and could cut as low as 35 strokes per minute. There are times when I would like to cut at a slower speed, but I'm not sure if the motor could handle running 1/2 speed for hours at a time without overheating.

 

[talvare]

I agree with Jim Dawson. Sometimes operating a vintage electric motor with a VFD can be a fatal combination for the motor.

Ted

 

[tjb]

I am a fan of the RPC. I know there are lots of good options with the VFD, like speed changes, but you need one for each piece of 3-phase equipment you end up with. A good RPC can be wired into a sub panel and you can wire the entire shop for 3-phase off one unit. The other advantage, at least for me, is that you just plug in your three phase equipment and run it. Nothing to rewire, or bypass or program. You get full power. All the control circuits and switches work like it came from the factory. If you have other motors on your equipment like coolant pumps they do not need to be changed out. Old three phase motors are cheap and can be wired to a phase converter panel. Several companies sell just panels.

That's the way my shop is wired, too. I started with one piece of 3-phase equipment. That soon became two, now three, and a fourth that will allow me to sell the first. As of right now, all four run on a single RPC. I wired four outlets in my shop - not because I wanted four pieces of 3-phase equipment, but because that allows me to put any of them anywhere in the shop. In my opinion, another advantage of an RPC is that it opens up opportunities for equipment that are not available without 3-phase or, as you've noted, without additional marginal cost every time you acquire one.

Regards