3 phase converter question

teachingscience · Feb 19, 2014

Hi all, I was fortunate enough to get a great deal on a doall milling machine. I need to buy a 3 phase converter and need some advice on which one. I"m not ready to get a rotary converter yet but two static converters on fleabay look promising. I looked a phase-a-matic and American rotary brands. They both sound pretty good.

Question 1:
have you used either and have a recommendation or have another brand you think is better.

Question 2:
Will these allow instant reversing and/or the use of my power feed (it is 3 phase also on this machine)

Thanks to all for your great advice.

Charlie

Janicholson · Feb 19, 2014

Be careful. The milling machine has a starting draw that is substantially larger than its run current. Reversing a 3 phase is internal to the motor controls. Never use the converter to reverse the system. I do not know what controls are on the Doall machine, but any electronic controls need correct phase relationship. A three phas motor of the correct amp capacity can be made into a rotary supply. Many diagrams on the Net. Jim

teachingscience · Feb 19, 2014

If the static will work, I plan on picking up a used motor first chance I get and hook up to the static converter and change it into a rotary. ( If I understand it correctly I should be able to do that) Right now I spent my budget on the mill and don't have the green for the rotary converter yet.

huntingreen2day2 · Feb 19, 2014

I used a static converter on mine without any problems. Let it stop to reverse it. I bought a 7.5 HP lathe and bought an American Rotary control to make a rotary phase converter and it has function well.

Frank 41 · Feb 19, 2014

I have tried keeping 2 of them running on grain bins. The owners were to have gotten 3ph but 2 neighbors backed out of requesting 3ph. Instead of giving them low volt 3ph, they got stuck with converters. Later IL Power dumped the maintaince on us. About every other year they needed something, usually capacitors. Mice loved them.

big jt · Feb 19, 2014

I had a Phase O Matic when running a static convertor. Did the job OK.

All statics need to be sized to the motor and this was part of the problem I had. Was using it on a Lathe with a two speed motor and since the low speed was half the HP of the high speed I didnt' have a low side to the motor (the convertor would just keep thumping).

What I am getting at is bigger isn't better in this case. If you have a 5 horse motor don't get a 10 horse convertor figuring bigger would hold up better. It will keep "thinking" the motor hasn't started and keep trying to start.

One other thing with Statics is you are only running on two thirds of the windings and thusly only have two thirds of the power.

I only use my machine tools occasionally but have never regretted getting a rotary. BTW I added the rotary after adding a mill.

Also no problems getting oversize if you are getting a rotary.

hth

jt

big jt · Feb 19, 2014

One other thing related to a static convertor. Your table feed will only work if the main powerhead is running. See my comments on sizing below.

The main motor will act as a slave to power the feed.

buickanddeere · Feb 19, 2014

If I may suggest a variable frequency drive ? The price is down and the reliability is up compared to just a few years ago.
There are even current limiting options so there is less damage should a jam occur.

3 phase converter question

teachingscience

Member

Janicholson

Well-known Member

teachingscience

Member

huntingreen2day2

Member

Frank 41

Member

big jt

Well-known Member

big jt

Well-known Member

buickanddeere

Well-known Member

Similar threads