Phase converters

[brimy311]

Been looking for a good belt sander, but all are 3phase ones....

So i have been trying to figure out if i should just bump up and get a Converter of some sort. I might be in the market for lathe in the next year, so i am kinda confused on what i should do.

From what i can find, there are two different converters

Static Converters about $200

and

Rotary Converters $800+

I was told that i would need a static converter for every machine if i went that route. Can i get away with running a static converter on a belt sander?

any info or experiences would be great

[willyswanter]

Static converters aren't near as nice as a rotary... You cannot run stuff with electronics such as a CNC machine on a Static converter. A static will run a manual lathe or belt sander though.

I built a 14hp rotary phase converter for under $600

http://www.norcalbigdawgs.net/Gallery/albums/albun69/MVC_550F.jpg

http://www.norcalbigdawgs.net/Gallery/albums/albun69/MVC_555F.jpg

[pigpen62]

I've run a static converter on my Bridgport Mill with DRO's and power feeds with no problem. My understanding is that you would lose about 1/3 of the power (1 leg) but if you can handle that, its not a problem. Rotary is better, but not necessary.



You cannot run stuff with electronics such as a CNC machine on a Static converter. A static will run a manual lathe or belt sander though.

Willys what do you mean by this/why?

[fj40guy]

Buy a "static convertor" to start with.

Say you found a 1hp three phase sander.

Then buy a static convertor rated for something like 1hp to 3hp.

Then buy a SURPLUS 3 phase 3450 rpm motor. In this
case buy a 3 hp one. Now the static convertor will start this
motor. Not hooked up to anything, just sits there spinning.
The Back EMF (electrical force) will great the three phase.
You can start and stop any other machine that is rated
up to 1.5hp without using the static convertor.

There is also something called a "VFD" Variable Frequency Drive.
I have mine wired for single phase power. It creates three phase,
but can vary the output frequency from 30 to 120 Hz. This will
fool my mill into changing speeds over a 4:1 range. Belt drive mill,
so that helps in not having to change pulley ratios as often
(actually the VFD operates over a wider range, but the motor
gets too hot I I slow it down too much).

Willy's.... nice setup, but 15hp idle motor? Do you have a 10 hp
motor on that milling machine?

Tom :usa:

[Rockrat]

I have a 5 hp, 10 hp, 15 hp and a 30 hp if your interested in one i will be seeling all of them. All are rotory. also Heavy

[brimy311]

So to loose 1/3 of a 1 HP motor, seems like alot. Rockrat, sent you an Email.

[Rockrat]

I will give you a shout tomorrow Brian

[pigpen62]

Never noticed the loss.

[Rockrat]

Never noticed the loss.

You wouldnt with DRO but if you ran Fanuc, seiko, dynapth or any other CNC controler you would they do not like fluctuation in power on there circuits. I had to use a 30 HP Rotory to run a 7.5hp Lathe which is about as hard start as they come due to the gear heads and load draw on spindle start

[OCNORB]

I have a small rotary converter that came with my mill when I bought it. There are plans for building your own online.
http://www.homemetalshopclub.org/projects/phconv/phconv.html
http://www.metalwebnews.com/howto/ph-conv/ph-conv.html
http://www.team.net/www/shop-talk/hm3phase.html
A local damaged goods store near here always has 3 phase motors for dirt cheap- noone can use them but industrial users. I picked up a new motor for my old southbend for $17.50.

If my mill had not come with one, I would have gone with a small VFD. They pop up on ebay all the time for $200 or less. Here's a 1HP for $99
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=42895&item=3846004854&rd=1

Hope this helps.