Transformer help

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Transformer help

Post by lukebarber » Fri Apr 21, 2017 12:30 pm

Hello guys,

I have 2006 CNC 3 axis Bridgeport/Harndinge EZ Vision Mill.

My machine is wired for 3 phase 460 volts.

2.0 KW
3.3 amps and 1.1 Spindle amps

My question,

I only have single phase 240 coming in the shop.

I also have a used SEW Eurodrive VFD. ... atalog.pdf

What kind of transformer do you guys recommend to boost the volts from 240 to 460? Installed before or after transformer?

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Re: Transformer help

Post by cnsperf » Fri Apr 21, 2017 1:32 pm

I had to do something similar for my CK-21. I went single phase 230 to a rotary phase converter to create three phase 230 and then from that to an Acme transformer to create the 460 three phase power. Do a google search for Acme Transformers in Lumberton, NC. Call their engineering group and tell them the info and they can make sure you get the right equipment. They are very helpful.
Christopher Racing Engines
Roanoke Rapids, NC 27870

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Re: Transformer help

Post by crazyman » Sat Apr 22, 2017 3:18 am

I've always considered having 3 phase installed if I ever build a house. Less $$ to run the A/C and well pump.

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Re: Transformer help

Post by j-c-c » Fri Jul 07, 2017 10:24 pm

What did you finally do? The VFD drive looks to me the Model #3 is not large enough and or borderline? I have never checked but do they make rotary step up convertors? I don't believe so. I also wonder how sensitive the CNC electronics are to use of a rotary converter. Is this a daily often used piece of equipment? May want to get a small 15KW? 3 Phase diesel genset that has 480 V capibility or iuse a transforner, or whatever size needed for facility emergency back up, and use that until a better solution presents itself.

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Re: Transformer help

Post by BigBlocksOnTop2 » Fri Jul 07, 2017 11:02 pm

Are the motors set up with low voltage wiring (dual voltage)? With 460 volts the current is 4.5 amps. With ''house voltage'' (usually 240 VAC) the current would be around 9 amps and that is not taxing. Now I'm not sure about CNC electronics, but as far as powering up, I would look into a rotary 3 phase converter (you have to have 3 phase). I made one from a 3 hp, 3 phase 230/ 460 VAC motor and several lighting capacitors years ago and wired it for low voltage. It works great and powers up 2 small lathes and 1 small mill. Three phase motors usually come dual voltage. I would not go the expense of an additional piece of equipment (step-up transformer).

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Re: Transformer help

Post by gofaster » Tue Jul 11, 2017 9:45 am

On 480v 3~ motors there is usually a diagram showing the pigtail configurations for different voltages. If there is not a diagram, an electric motor shop can reconfigure it for you. I had a motor on my milling machine that did not appear to have any pigtails to change it from 480v 3~ to 240v 3~. I took it to the local electrical shop and they pulled leads out somehow to make it work, and they only charged me a small fee. It was over 20 years ago and I'm a little bit fuzzy on the details. I'm still running my mill with the same motor.
Jim McMahon

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