Making a rotary phase converter????

I have several 7-10 HP 3 phase motors I have collected over the years. Can I just drive one of them with a single phase 220 volt motor??? Then use the generated 3 phase current to run any three phase equipment I want to???

I remember a local guy had one he had made. If I remember right he had to spin it as he started it.

I am thinking to just wall mount this unit and run some wiring and plugs through the shop to anything that is 3 phase.

So tell how crazy I am. LOL

I know it would be along post but.......

Hey JD.

I completed one recently and am in the process of hard wiring it in my shop now.

I have details if you are interested.

Brad

You can spin it with a 110 volt motor, about 1/2 hp or more. You do wire the 3 phase to 220v, and the motor generates the third leg. You could even spin the 3 phase with a rope, but a little motor works fine and is safer. You shut it off once the 3 phase is running. Mine works fine and cost little to nothing to make. Google home made phase converters for diagrams and pics.

Check for out the typical "For Sale" lists in you area... you may be able to find a "Roto-Phase" unit ready to go for a reasonable price.

If you want to build you own, here's a link...
Practical

If you use capacitors to shift the phase a little you don't need any kind of dangerous manual start. Look up the ones that use caps.

This is a pretty common application and there is a bunch of discussion in various "shop" type forums on the subject. If you use your favorite search engine you can come up with an abundance of ready made designs and work arounds for the limitations.

Somebody will chime in on the benefits of a variable frequency drive for this application. They all make sense, but I kind of look at like if you have all the pieces and don't mind spending the time why not do it. Once you come up with the materials list of stuff you will need to buy you should go back and look at the VFD option though. They are really inexpensive anymore.

From what I understand that will work but not very good. You need capicators to bump up L3 to compensate for the power loss. I'm getting 220v on L3 on my rotorary phase converter.

(quoted from post at 08:54:31 11/02/14) I have several 7-10 HP 3 phase motors I have collected over the years. Can I just drive one of them with a single phase 220 volt motor??? Then use the generated 3 phase current to run any three phase equipment I want to???

Click to expand...

That's what I've done successfully for 30 years. I've used static, commercial capacitor rotaries, and a couple of homemade no capacitor rotaries. I settled on a 5 hp 3Φ motor with a chain drive gear. Kick it twice to get it spinning, then switch on the house current. Modern Unisaw, Babbitt 12" jointer, Silver 36" bandsaw, twin spindle shaper, and dust collector all like it just fine. As many as I ever wanted at one time.

It's really that simple, and the lost tool power I never missed.

Just like the others said. Get your three phase motor spinning and then throw 220 to it.

I played with doing this once and wound up getting a rotary off ebay.

Couple of thoughts. You can get it spinning with a static convertor or use a motor like I tried. A 1/4 or 1/2 will be more than sufficient, you just need to get the mass spinning and then you will cut power to the starter motor. This is where I ran into trouble though. The starter I used when power was cut but it was still part of the spinning mass created a fair bit of drag, till I shorted out the leads going to the starter motor. I am sure someone who is far more knowledgable about such things can explain what was happening. I just decided to ditch the homeade idea and got one that has the proper stuff.

jt

Just bought the 3HP version (NES1-022SB)of this drive. Has not yet arrived. 220 single phase in, 220 three phase out. Can vary the motor speed.

$258 with shipping and the variable operator (NES1-OP) Inverter Mounted Operator w/Speed Potentiometer. Replacement for Standard Operator on NES drives.

Going to run a lathe and someday, hopefully, a mill.
VFD

I made a 10hp phase converter that is self exciting to start and run with the 10hp motor.
There is an outfit that is about 50 miles from me. It is near Niagara Falls and the name is WNY Supply. They sell on ebay or thru the company itself.
Mine cost about $125 a few years ago. There is a lot of controversy on the web about phase converters. The only thing I have to say is I get 120 volts on each line. Have run digital readouts with no problem.
The only thing I did is build a box outside my shop for the 10hp motor(switch and capacitators in the provided box inside)] because the motor was a little loud.
Have put an awful lot of hours on it and zero problems even on heavy loads.
I just punched in "Phase Converter" in ebay and the fellow is selling the unit for $125 to $150 and he is very good explaining any questions.

If you are an electrician you can almost build these for free . [well if you save stuff]. It used to be the only thing needed was a 12x12 pull box to mount the starter and caps in and put your start/stop buttons on the cover.. My friends dad was a GE motor distributor and free motors were abundent.

My dad would start the rotary phaser just like you would with a static phaser using run and start capacitors. He would cut the shaft off for safety. Sometimes he would use lathe to shave a little off the rotor. Once you get the rotor motor spinning, connect you second load motor to the 3 wires of the rotor.

I've has a good 5 hp 3 phase motor sitting on my shop floor for the past 30 years thinking I may some day need to make one. Well that hasn't happened yet. Just as soon as I get rid of it, I'll need it. I also have collected 3 phase contactors and buckets full of old AC run capacitors and a few start caps.

If I recall your rotor motor should be the same size or larger than the load motor, depending on how many motors you want to run off rotary phaser.

Have used a homemade 5 hp rotary for years now, a capacitor and a adjustable time delay relay works well to make it a self starter, just put the capacitor to the 3rd leg and a quick time delay to switch it out when running, starts just like an electric motor. Before the relay I wrapped a rope and started it like a old lawn mower

I tried that a few years ago would be curious how it does.

The single phase motor turned in the 1725 to 1750 range. At that rpm I could get voltage but no significant current.

I never tried it again but I think the 3 phase needed to turn a true 1800 to get current. Someone else may know more about this.

I built a 7.5 hp idler and it starts my 5 hp lath just fine on low speed. It won't start on high speed most of the time although you can start it in low and flip to high.

To start directly on high I add another 5 hp motor. Another 3 wouldn't do it. Getting the current to balance is a cut an try thing. It's like that one older guy I talk to, this is an art.

RT (This is the short version.)

I can't find where I found the info I used when building mine, but all you need is the correct capacitors to both start, and run the motor, and your good. In other words you do not need a separate motor to start it.

With mine, I've got start capacitors wired in to provide the 'third leg' to get the 3 phase motor spinning initially. I did this by using a starter that momentarily makes the connection when I hit the start button, and then drops out when the button is let go. The motor is kept spinning by the two main 220V legs going to it and being maintained by a second starter that's wired to hold in when the start button is released.

I used a 10HP three phase motor for the converter, and got the other parts out of various well pump panels that had been replaced by the company Dad works for. I built it nearly two years ago, and have had absolutely no problems starting either the vertical spindle on my mill which is 5HP, or my lathe, which is also 5HP. The only thing that makes it struggle a little is the horizontal feed which takes a little more juice. In that case I simply fire up the vertical feed first and let it also act as an idler, and then start the other. Once running I can shut off the vertical motor, and do what I need to do.

Ultimately it's not rocket science. Given all the things I've seen you post about on here, added with a little research on the net (all I did), it's really easy to build one that will work for you with absolutely no problems. Too, it's a lot cheaper than going out and buying a new one where the only difference is someone else did the thinking, and wiring for you.