phase converter - how to run 3 ph accessories on machine

First, I barely know enough about electrical things to ask this question. Please excuse my ignorance.

I just bought a used lathe which should have a 1.5 HP 3 Phase motor. (this according to specs, I don't have the precise details off the motor as I don't have the lathe yet) This machine has a built-in coolant pump. There is a control panel on the front to run various functions such as on, off, forward, reverse, pump on and off.

I want to feed the lathe whatever it is already wired for so the factory controls work as intended. I don't really care about variable speed control as the lathe has a mechanical version built in.

What seems like an obvious solution is to introduce a phase converter device that is wired into my garage's single phase power that allows the cord and plug on the new machine to simply plug in to a matching receptacle connected to the converter device. I assume that the machine would then be controlled from its front panel as intended when it left the factory. Attached is a photo of the plug on the machine now.

Something like this perhaps? --- http://www.factorymation.com/s.nl/it.A/id.5577/.f?category=15367

Am I on the right track?

For that, a rotary phase converter is ideal. That, or separating the power and driving the accessories from a small RPC, and main from a VFD.

You probably don't want to switch the stuff on and off driven from a VFD.

An RPC would give you 3 phase that wouldn't care how much you switched it.

So with a rotary phase converter I would have the option of simply plugging the lathe into the converter and running as if I had "real" 3 phase? But not with the device I posted the link to?

I want a "magic box" that makes single phase into 3 phase to plug this lathe into. I want to be able to walk over to my lathe and turn it on with the switch built into it. No flip three different switches on the wall and pull start another old motor while kicking the cat and jumping on one foot. Simpler and cheaper is great as long as I get 100% out of my lathe. But I'll pay a little bit to get it working hassle free and reliable.

Sorry for the lame questions. I'm obviously confused about the electrical devices y'all are building and talking about here.

This is as bad as stopping to ask directions.
Guys don't do that.

Not that I've ever had to ask directions or anything like that.

RPCs - simple to complex

henrya said:

So with a rotary phase converter I would have the option of simply plugging the lathe into the converter and running as if I had "real" 3 phase? But not with the device I posted the link to?

I want a "magic box" that makes single phase into 3 phase to plug this lathe into. I want to be able to walk over to my lathe and turn it on with the switch built into it. No flip three different switches on the wall and pull start another old motor while kicking the cat and jumping on one foot. Simpler and cheaper is great as long as I get 100% out of my lathe. But I'll pay a little bit to get it working hassle free and reliable.

Sorry for the lame questions. I'm obviously confused about the electrical devices y'all are building and talking about here.

Click to expand...

Ok- there is TONS of info on this, but here goes.

1. With a rotary phase converter, once it is running, you have 3 phase power and your machines will work just fine.*

2. There are a few types of RPC. The simplest is just a big 3 phase motor. Put in 2 phases, get out 3. But you have to get it spinning first. This is called the idler motor.

3. Wrap a rope around the shaft, and after you turn on the power, pull the rope. Super low tech, but works.

4. Use a small single phase pony motor to get the big one spinning. Also pretty low tech.

5. Have a momentary push button that you will have to press for a few seconds after you turn on the power to the idler motor. This causes the idelr to start spinning. Once it is spinning you let up on the button.

6. The ultimate is a fully automatic one that starts the idler spinning automatically.

So- these choices are increasingly complicated, but none are terribly so.

Also- bear in mind that it is pretty economical to leave the idler running the whole time you are in the shop. Because of various things, the motor without a load doesn't spin the power meter much or at all. So spin the motor when you turn on the lights, and kill it when you leave. Simple.



* assuming you have sized the RPC correctly. also, there is the notion of balancing the generated leg to have it work perfectly, but ignore that for now.

you want a mfg. rpc
you could hook up your stuff just as you want
and have only to turn it on to run everything else


know comes the hard part

take your index finger
push the green button to start rpc

not so hard

henrya,

Where in Tennessee?

Bruce Norton
Kingsport, Tn

take your index finger
push the green button to start rpc

Click to expand...

Yep, thats it!

So who/where is a good source of manufactured rotary phase converters?

toolnut,

I'm just south of Nashville.

What are the good choices in RFDs?
Who to buy from and who to stay away from.

Thanks for all the help.
I appreciate it.

I've used a Phase-a-Matic and right now I use an American Rotary Phase Perfect. Both do the job fine. All you need is a 220 breaker and your good to go.

Just remember keep the wild leg of the phase converter out of the control circuit of your machinery. Control circuits run off line one if 120v or line one and two if 240v, so always hook
the wild or "extremely high voltage leg" of the converter to L3 to prevent trouble,.........Bob

Yep, thats it!

So who/where is a good source of manufactured rotary phase converters?

Click to expand...

never bought one so i can't help there

but a google search should get you on the right track

look through old posts in this section there are many comments on brands

Well, the small Arco I have is now at least 25 years old, and still works fine. I'm the 3rd owner.

it needed a little help due to mechanical damage (something hit it) but nothing electrical was wrong, when I got it.

I'd say that was a recommendation.

Thanks, folks!

I bought and set up an american rotary RPC a few months ago, and i'm completely happy with it. they run sales on their ebay store here and there with free shipping, or a $100 discount. i picked my 10hp rpc up for about $680 delivered. if you don't already have a 3 phase motor to make your own, you'll find this price isn't too much more than a used motor of the right size. at least the goign rate here in utah, copper is worth a bunch.

wiring it in was easy, just ran lines from the breaker box to it, and wired my mill into it. it has a start and stop button, and my machine has a breaker on the input so that covers everything.

good luck,
Mike

Henrya

An often overlooked point is that, by their very nature, RPC and transformer type static converters tend to buzz and grumble a bit. My pal Mike has a "room in a barn" style shop and put his Transwave RPC in the barn rather than the shop because the noise was distracting. Shop wall is twin 5/8 OSB sheet on 4 x 2 insulated and you can just hear the RPC from inside. Just enough to know its going.
Being slow on the uptake I put a Motorrun static converter on a shelf next to my Bridgeport and pretty much drove myself nuts with the noise. Noise is proportionate to how far out of balance the phases are. I converted it to an RPC by adding a pilot motor which hushed things a bit but not enough.
Prolly best to put it up the other end of the shop and spend the extra for an auto-balancing one.
Got an electronic 7.5 HP one now with isolation transformers. That is at the other end of the shop. No transformer buzz but it has got two cooling fans which hum a bit.

Clive