Rotary Phase Converter Idea

[Rich Riddle]

After reading posts from various woodworkers concerning rotary phase converters that have the generated leg unknowingly "spike" and risk potentially hurting one of the machines, I decided to kill some time and add volt indicators for all the phases on the front of the converter. No more worries about unknown high voltages. Just remember to look at them once in a while. It was quick to add the meters and send the voltage through a 1/4 amp fuse for each meter. As you can see the voltages aren't perfect, but they are tolerable.

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[Bruce Wrenn]

In line with what my shop made RPC that I built for my neighbor produces. You are looking at a 3 % difference in voltage. Our voltages are higher, but input voltage is 245 volts.

[Benjamin Miller]

That's pretty darn good. The wild leg on my 440V phase converter was over 500V the last time I checked, but it's been powering the milling machine for almost 30 years now...

[Rich Riddle]

It should be noted that the input voltage from the line is the top meter at 247 volts, not the other two at 239 volts each. The top meter measures between the two "split-phase" hot legs from the power company. The middle voltage meter is measuring between the first "split phase" provided by the power company and the generated leg. The bottom meter measures between the second "split phase" provided by the power company and the generated leg. All the wiring stays on the front panel. A trailer wiring harness connects to the front panel and than its counterpart connects to the rotary phase converter. That way if/when one needs to remove the front panel, you simply disconnect the trailer harness.

[Duane Meadows]

Deleted post. Sorry Rich. Just couldn't see any advantages to the fuses. Didn't mean to be offensive.

[Rich Riddle]

Duane,

First off, you come across like a total jerk. There are ways to ask questions and do it in a polite manner, but you chose the jerk route. After writing this I will simply block you. To answer your questions, the meters indicated they are rested up to 1/2 amp, so I installed a 1/4 amp fuse to protect the meters, yes. One need not see the voltages every second. Others indicate the voltages of rotary phase converters "climb" over extended time so these were installed to detect the "climb" if it occurs. Since you have to be at the panel to start the RPC, you can immediately detect if the "climb" or degradation of components has occurred. If it has, one needs to either detect which component to replace. Now that you know the answers, away troll.

[Dennis Nagle]

I think it is a great idea Rich. I run my Oliver 20D lathe, Crescent 26" bandsaw, and two Rockwell buffers off a phase converter and I would like to know the line voltages. Can we talk you into putting together a parts list and schematic???

[James Tibbetts]

[QUOTE Can we talk you into putting together a parts list and schematic???[/QUOTE]

Second that request. Great idea!

[Larry Edgerton]

[QUOTE Can we talk you into putting together a parts list and schematic???

Second that request. Great idea![/QUOTE]

Ditto. Plus, it looks really cool!

Larry

[Rich Riddle]

I will use the Bay for part examples. Some of these examples ship from China but get here in short amounts of time. Even the ones you purchase here were made there.

The fuse holder is a panel mount fuse holder that has a nut on the back (make sure you get this kind): 5mm x 20mm: 10A 250VAC 15A 125 VAC model. Each one of the fuses has the 125VAC go through it. Currently, you can look at item 351028422307. You will need three of them. Here is a non-Bay link: http://www.newark.com/bulgin/fx0455/...nt/dp/06WX9443

The digital displays are AC 80-500V 3 1/2 Blue LCD Digital Voltage Meter. Currently, you can look at item 371027430704. You will need three of them. Here is an Amazon link: http://www.amazon.com/SMAKN-80-500V-.../dp/B00FVIO17O

You will need 1/4 amp 5mm x 20mm fuses. Currently you can look at item 121298894640. When that item number link dies, here is another link to see them. http://www.mcmelectronics.com/produc...A-C-/74-5FG10A You will need three of them and extras.

You will need a simple 4-wire trailer light harness. I did this so I could remove the door from the main unit and simply unplug it. See the below photographs. You can purchase these almost anywhere, but Walmart has the item listed here for six dollars:

http://www.walmart.com/ip/Hopkins-To...t-Set/16782546

You will need a "terminal strip" or "barrier strip" to connect the wires on the back of the panel. See the photograph. I prefer the kind that has the wires tucked away as those that leave the wires exposed, but it's up to you which you prefer. Here is a link to the terminal strip (cut it so that you only have three rows):

http://www.radioshack.com/product/in...ductId=2103986

Here is the terminal strip:

http://www.radioshack.com/product/in...uctId=18108666

Either is held in place with five-minute epoxy.

Of course you will need solder, flux, liquid tape to put on the back of the fuse holder, epoxy, tools, etc.

I show the back of the removable panel here.

Plate RPC.jpg

And here is the inside of the Rotary Phase Converter where you can see one half of the trailer harness attached. Note that the side of the harness mounted inside the RPC has the voltage enclosed in the harness. Don't hook up the harness with voltage on the one "exposed" lug of the harness.

Inside RPC.jpg

Wiring diagrams explanations to follow.

[Brian Backner]

Rich,

How did you cut the rectangular holes in the panel? They need to be reasonably close to exact dimensions so the meters will snap into place and stay there. I have a set of three voltage meters (I chose to use a different color for each leg, though) exactly like this just waiting to get installed on my 15hp RPC, but am stalled as I refuse to spend the $80-90 for a rectangular punch.

Cheers,

Brian

[Rollie Kelly]

If you are really concerned about Phase V differentials add a VFD after the RPC. The VFD will make them close enough.

Rollie

[Benjamin Miller]

If you're going to add a VFD, you might as well just skip the phase converter to begin with. The first thing VFDs do is rectify to DC.

Rotary phase converters are still useful because they are cheap and easy to build, and for many applications you don't need speed control. I can't fathom needing a variable speed jointer, planer, or table saw...

[Rich Riddle]

Brian,

I cut a large hole in mine and made a wood panel to which everything was installed. Cutting the holes in plywood proved easy. I don't like those little tabs and removed them and installed the meters to the wood with epoxy. That said, I cut rectangular holes in metal with great accuracy using a Craftsman "All in One" tool. Dremel makes one exactly like it. Simply place the right angle wheel attachment on it and carefully cut to the line. You can file when close enough. I use that tool all the time so it was no extra expense. It also has a wood blade so one can use it to cut wood.

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