Phase convertors, wires etc. etc.

JBS TOOLMAKER

JBS TOOLMAKER

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May 4, 2009
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In my quest for a mini mill I have had an awesome deal fall in my lap. It's an older Hardinge Mini mill. Its tight....not much slack. Two drawbacks it uses 4c collets hard to find but it does have a full set, No. 2 it's 3 Phase what are my best options to convert to 220v ? Have the existing motor converted, buy a new motor, or is there a phase convertor that will be compatible? The man is willing to trade for a couple of my knives.
If anyone has dealt with this please tell me the good and bad.
 
Running most 3ph equipment is easy with a Rotary phase converter. Sounds like you can spend the money you were planning to spend on the mill on the converter instead.

This will open up a lot more possibilities for good deals in the future. I run half the machines in my shop off one.

You'll need to find out the cumulative hp of all the motors the machine has, and as a general rule, you'll want a rotary converter's idler motor to be approx double. Some machine that are hard starting and draw a lot of amps like compressors, require much bigger generators to run, but the 2x rule applies to most.

I initially used a home built converter, and that can be the cheapest way initially, but you can run into issues, and the power consumption can be much larger than a professionally built unit.

Most of the pros I know, recomnend the Gentec/American Rotary units, which have specially built Baldor motors without shafts designed specifically for these units. After I blew up my home built unit, I bought one on sale, 10hp, digitally controlled, cnc compatible, and its some of the best money I ever spent.

It runs great, quiet, and even though I went from a 5hp home built job, to a 10hp pro unit, my power consumption hasn't increased that I've noticed.


My only regret is that I didn't get a 20 or 25hp unit.

If you check them on ebay (american rotary sells direct and they have an ebay store) you can sometimes find some good sale prices.
 
How much hp? You can get up to 3 hp 240v 3phase output with a 240 v single phase input. That will likle be your best bet. Do you need Nema 4 rating on the case? Ou might not. Fo you have a vfd for a belt grinder that allows variable speed?
 
javand said:
Running most 3ph equipment is easy with a Rotary phase converter.

You'll need to find out the cumulative hp of all the motors the machine has,
Click to expand...

PT Doc said:
How much hp? You can get up to 3 hp 240v 3phase output with a 240 v single phase input. VFD
Click to expand...

Good points

My first instinct is to go VFD

but

How many motors,
What HP
and what voltage, are they all the same ?
ie main, coolant pump, travel feed,

VFD's will easiliy go from 220 single phase to 220 3 phase, but having to jump up to 440 or 550 (if the motor isn't dual voltage) needs a transformer and that can be pricey,
at that point, i look at motor rewire, or swap
some motors have special mounts or shafts and a rewire is cheaper, some motors are very common and easy to swap and keep the origional if desired for resale of collectivity


the VFD's will give you variable speed which can be nice.

a VFD will control a motor and speed, but if you have more than one motor, you can't control them independently unless you have a separate one for each motor.




let's start by seeing good photos of the data plates on the motors.
 
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Thanks guys for all the quick responses, I'm going back this week to look it over again and nail down a deal. I will get all the info and see what I need.
Sounds like a phase converter will be the way to go. The little mill is just to solid to pass up even if I have to get a new motor.
 
Just one motor and 3 hp or less, I suspect you can VFD, converter, or change motor for 300 or less.
 
I've been looking at a phase converter for my new shop as I'm considering a three phase motor for my forge press I'll be building.
This is what I've found. A rotary phase converter only costs 7 cents an hour to run on average.

Hard start items need to have a converter double the HP of the motor being run. Hydraulics are considered hard start. I'd get a 10HP minimum.

I'd been shopping for a 3ph mill before I bought my mini-mill. I'd have just gotten a second KBAC VFD for one if I'd have found one. Most of the Bridgeports I was looking at were 2hp or less.

Here's a link to the company I was recommended for a phase converter.

http://www.americanrotary.com/products/phase-converters/rotary-phase-converters
 
A static converter will work but they are very specific as to the HP they will run. So you basically have to get one for each machine you will be running unless they are all within .5hp of each other. Rotary is great and I wish I had done it a long time ago. Nice to walk up to a machine and just turn it on. Esp machines that have their own speed control or do not require one. If you only have one or two motors to convert/control a VFD will do you just fine. You may also wind up with one or two anyway just cause they are really nice.

Now all of this is solely dependent in you having a 220vac 3ph motor to control Like the count pointed out if you are high voltage then you are SOL without a transformer, unless you have a commercial building wired for it.
 
Yeah VFD could be the best option if the mill doesn't already have some sort of easy speed change. If it has some kind of variable or quick change gear or pulley based speed variation already, then the rotary would be a much better investment imho.


Static phase converters can seem like a cheaper option, and can be a valid choice in some cases, but its highly specific. They supposedly don't generate 3 phases cleanly and can be detrimental to the motors while also not supplying the full hp.

I'm not an expert, so I want to make it clear that this is just "as I've come to understand it" type info. I'm sure someone else here knows a lot more about it.

Nice thing about my American Rotary unit. Push a button and it comes on, all my big machines are wired into it, and I can run any or all of them at the same time.
 
I recommend against messing with the motor on the mill. It is most likely a specially balanced motor and replacing it or rewiring it will most likely reduce the quality of your surface finish. Quality machine tools don't use just regular motors on their spindles.

I believe that static phase converters simply start the 3ph motor with a momentary blip of "three phase", then the motor runs on two legs. A VFD and a rotary both provide three legs.

I got a static converter for an old Bridgeport many moons ago and still use it for that because the little motor just doesn't justify firing up the big rotor phase converter. While the motor only develops 2/3rd rated HP, it has never been a problem. For a while I ran a press and a grinder on it too. If you go ahead and start whatever motor the unit is sized for first it will act as a pony so you can then start different sized motors on the same circuit.

I looked in my crystal ball and I saw an older industrial CNC mill in your future. When that happens you'll end up getting a big rotary unit too....
 
I looked in my crystal ball and I saw an older industrial CNC mill in your future. When that happens you'll end up getting a big rotary unit too....[/QUOTE]

Full production folder madness!! How about I design one...you machine them..... we split profits 50/50 :D
 
JBS TOOLMAKER said:
I looked in my crystal ball and I saw an older industrial CNC mill in your future. When that happens you'll end up getting a big rotary unit too....

Full production folder madness!! How about I design one...you machine them..... we split profits 50/50 :D
Click to expand...

If you split the costs and do the finish grinding, assembly, marketing and distribution, you got a deal...

Seriously though, everybody needs a cnc mill (it is the year 2012 you know), and I figure you probably need a full-on VMC.

The problem, of course, ends up being an issue of space. Hence the need for minimills. My last mill was a mini mill (of sorts), due to space (and power) issues.
 
Just no room in my 2 car garage knife shop, I need save some paper and build a shop. Just not in the budget yet. It is frustrating when you have an idea and you know you could blast it out on a CNC within the hour. When you look at a sketch or a print do you see lines of G-code?
 
JBS TOOLMAKER said:
Just no room in my 2 car garage knife shop, I need save some paper and build a shop. Just not in the budget yet. It is frustrating when you have an idea and you know you could blast it out on a CNC within the hour. When you look at a sketch or a print do you see lines of G-code?
Click to expand...

After I design a fixture to hold it in my head then the G code starts.
 
JBS TOOLMAKER said:
Just no room in my 2 car garage knife shop, I need save some paper and build a shop. Just not in the budget yet. It is frustrating when you have an idea and you know you could blast it out on a CNC within the hour. When you look at a sketch or a print do you see lines of G-code?
Click to expand...

Naw man, I don't. You and Chuck might need to take a vacation or something...

Honestly, I'm not very good at G-code. I couldn't tell you the difference between G85 and G86. I used CAD/CAM since I got started in the 90's so I never really programed manually very well.

Hell man, a two car knife shop? You can fit a lot of stuff in that kind of space.
 
JBS TOOLMAKER said:
Just no room in my 2 car garage knife shop, I need save some paper and build a shop. Just not in the budget yet. It is frustrating when you have an idea and you know you could blast it out on a CNC within the hour. When you look at a sketch or a print do you see lines of G-code?
Click to expand...

Park the cars outside, run a CNC to MAKE money and use that to build the new shop

It's all about perspective.
 
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