View Full Version : Mill and Phase Inverter Question

12-07-2005, 08:39 PM
I have two questions for the board if I may.

First, eventually I will have metal working equipment at home (don't know when yet but getting there). Anyway, I were to use the phase inverter here:


It looks like the power in/out lugs are exposed. Any suggestions how to keep chips off of them?

Second, question is a Van Norman #12 mill. How would you bore a hole with this mill? It does not look like the spindle moves. Would you move the table/workpiece?


Thanks in advance.


12-07-2005, 08:56 PM
I do not how many machines you are talking about but you may want to think about something like this:
In my shop I have a rotary phase converter wired into a 3 phase breaker panel( to produce the third leg), the other two 120 volt lines come from my existing single phase panel, Therefore producing a 3 phase breaker panel. I wire up my machines form this panel. You want to make sure that the rotary phase unit is big enough to carry the largest 3 phase motor in your equipment. Some say you need to add up all your h.p. on your equipment, but in my shop I am the only one that uses the equipment and the converter I use works well. I am using a 10 h.p. rotary phase converter that a friend of mine built for me. I am not an electrician but my system works for me. You are right in your thinking of not putting the cart before the horse. It is best to plan out your shop in as much detail as you can think of so there will not be as many suprises. Good Luck. This is just food for thought........ http://bbs.homeshopmachinist.net//biggrin.gif, http://bbs.homeshopmachinist.net//biggrin.gif

12-07-2005, 09:05 PM
I use a static inverter to make the third leg a bought it on Ebay for $70 bucks it is easy to wire up and hangs on the wall. It is a small box 8" wide and 10" tall. my milling machine is the only thing that i have that runs three phase.

12-07-2005, 10:09 PM
So far as boring in the mill you can-

#1 When boring vertical you can crank up the knee or #2 when boring horizonal you can crank the table.

I'm sure there are others,but those are the obvious.

If you get it,be sure and get the collets he has for it.

12-07-2005, 10:22 PM
Thanks for the quick replies.

Canman, most likely just a mill and lathe. It seems to me that the mill will almost certainly be 3-phase and the lathe quite probably. Rotary phase converts seem expensive to me (the little research I've done).

The static converters seem like a good option but I don't like that you don't get full horespower and the inverters aren't all that much more money.

Thanks again.

12-07-2005, 11:02 PM
Hi Jeff,

I don't know if you have thought of this already but you better bid on one of the sets of collets this seller has in another auction (or two). Those Van Norman collets (V5 I think) are difficult to get and your mill won't be much good without something to hold your cutters!

Just some friendly advice. Good Luck!
-Blue Chips-

12-08-2005, 12:01 AM
<font face="Verdana, Arial" size="2">Originally posted by chriskat:
Rotary phase converts seem expensive to me (the little research I've done).</font>

Au contraire - you need a surplus 3-phase motor and a $5.00 capacitor. A few switches and fuses would be nice, some wire and a box to put it all in. Very economical - the most expensive thing is shipping the motor if you buy one on eBay. At least a dozen web sites have instructions for wiring one up.

12-08-2005, 06:28 AM
Go to EBAY and type in phase converter.
I bought a brand new converter that came with a brand new dayon 3hp motor for $250 bucks. You can purchase a converter panel for $100 and use your own motor if you have one lyimg around. I decided to buy brand new with the thought of never having to worry about it ever again. It comes with simple wiring diagram.
They say to use a 3hp if the motor on your machine is a 1hp. DO NOT PURCHASE A STATIC CONVERTER. It will rob you of power.
Good luck and have fun.

12-08-2005, 10:15 AM
Static converter + 3 phase motor = rotary converter.

12-08-2005, 08:22 PM
<font face="Verdana, Arial" size="2">Originally posted by Evan:
Static converter + 3 phase motor = rotary converter.</font>

Lawnmower pull rope+3phase motor= rotary converter too http://bbs.homeshopmachinist.net//biggrin.gif

12-08-2005, 11:42 PM
<font face="Verdana, Arial" size="2">It looks like the power in/out lugs are exposed. Any suggestions how to keep chips off of them?</font>

I have a Hitachi L100, which also has exposed terminals, and mounted it inside an electrical enclosure made by Hoffman. A couple of rectangular openings were made in the bottom and top of the box and covered with metal speaker grille to keep out large chips while allowing for air exchange by convection to avoid overheating the VFD.


12-09-2005, 12:22 PM
<font face="Verdana, Arial" size="2">Originally posted by tws63:
Go to EBAY and type in phase converter.
DO NOT PURCHASE A STATIC CONVERTER. It will rob you of power.
Good luck and have fun.</font>

Second tws63's post. I got a 2HP SquareD VFD from ebay, and I love it. It produces full power and gives the added advantage of speed control. Cost me $110 plus shipping. I run my Bridgeport with it, and the speed control is nice because I don't have to mees with step-pulley changes nearly as much.

I understand that a static converter is basically a capacitor that helps get a 3 phase motor started, then the motor runs on a single phase. You get a lot less power and more heat in the motor. Wears motors out faster, too. Garbage, IMHO. Get the VFD.

12-09-2005, 12:43 PM
Ditto on Wirecutter. I originally had a static phase converter on my milling machine. It worked, but I could stall the motor pretty easily when drilling 1/2" holes. I got a VFD a few years ago. MUCH better. More money..but IMO well worth the money.

12-09-2005, 01:08 PM
On the other hand, I use a static converter on my Strands drill press. If it has lost power then I don't want it back. That thing scares me into clamping, bolting or otherwise holding the work, just not by hand. If it decides to whip something it won't be just a bruise, it will be removal of body parts.

I do intend to hook up the 5 hp 3p motor I have to make it a rotary converter but haven't seen the need yet.