CNC Mill Transformer
 

From our sponser we recieve a very very nice CNC mill and we have found out that the part they told us is the transformer is actually the battery backup. So we are in need of a transformer that will step up 208 to 440. I do not know what wattage it need to be but if you know anything about CNC mills you can probally figure it is wayy up there.

Re: CNC Mill Transformer
 

Is there a question in there? 208V is usually 3-phase, do you have that avilable where you are putting this? I think you really should just contact the manufacturer and buy the right part, although it will likely be costly, its less costly than fixing the machine if you feed the wrong power.

Re: CNC Mill Transformer
 

first off we wouldn't be feeding the wrong power if we are feeding it the power it says to on it, and why would be be inputing 208V if it needs 440V

Re: CNC Mill Transformer
 

Can you re-state that in a complete sentences using punctuation and correct spelling?

Can you actually ask a question? I still don't understand the point of this thread.

All transformers are not the same. Without the VA rating it's pretty hard to tell. Also, for 3-phase transformers I believe there are several different winding methods and other differences, so you probably want to get the correct one matched to your mill. Have you contacted the manufacturer of the mill to find out how much they want for the correct part?

Re: CNC Mill Transformer
 

I've never heard of a CNC mill having a battery backup. Can you describe this a little more. Is it just for memory to save the programs that are loaded in it?

Re: CNC Mill Transformer
 

Something that is initially mistaken for a transformer cannot possibly be a backup battery for a CNC. The only thing my shop's CNC needs is a small 9V battery to keep the programs loaded. A transformer would be really big. I think it is worth your money to have a professional electrician or mill repairman take a look at it. You dont want to bust your controller or anything, running it on the wrong power. It would cost a LOT more to get a broken stepper motor fixed than just to have a repairman look at it.

Re: CNC Mill Transformer
 

Why don't you ask you're sponsor, they should know everything it needs.

Maybe you could even get their electrician to wire it up for you, if they have one.

Re: CNC Mill Transformer
 

well we did have a professional electrician look at it and it says back-up battery right on it, I never said it was to keep the programs loaded, someone else did, and we donot know what it is for

Re: CNC Mill Transformer
 

There are many variables for different types of machines. It would very use full if you could tell us exactly what make & model this is..and include any other pertinent information to help you out...

Re: CNC Mill Transformer
 

Sparks,
The part of which you are asking can be one of about a thousand different transformers. As stated before, a 208 to 440 is usually a three phase device. The motor is wound for three phase and that is how it turns and has power. In an industrial setting there is usually 208 and 440 outputs available through the main transformer for the building. Now granted, the transformer you seek only feeds one device, but these transformers are usually very large in size as they are intended to feed a 200-400 amp load or in many cases something even larger.
What we need to know is the "plate" rating. There should be a plate on the mill that states input voltage and input current, horespower, single phase or three phase, etc. Most often it is near the power input but can be on the motor itself. I have heard that some devices actually have a transformer inside which must be strapped by an electrician for the correct input voltage. The connections would be behind a plate with electrical warnings. The warnings are there for your protection. Don't attempt any electrical wiring on this device, leave it to a pro.

Re: CNC Mill Transformer
 

Okay everyone is beating around the bush guessing what it could be and giving helpfull advice about CNC machines but its getting a little wound out. Sparksandtabs, What is the model nmber of the CNC and the battery and what information can you give us? (manufacturer, website, anything else)

Re: CNC Mill Transformer
 

Listen and read Al's writing, he is mostly correct, if not all correct. As an electrician I am going to tell you that the transformer you are looking for will be expensive ( a 32volt ( you would need a 232volt) cost around $800, in 1998 each, and there were 3 ( we installed a 3 phase service and the elevator needed to be run at 240 thus the buck-boost transformer) This would probably be much larger than yours would need to be but you get the idea ). Ask at the locating where you are installing this mill and see if they have a supply of 440 3phase, but you will also have to find out if the mill requires a Y type or Delta. Which are the two most common for a three phase setup. IF there is 440 available in the building see about getting it run to the location ( From the main panel room) to the room which the mill will be in. Another option you could do is see about getting a different motor running at 208 ( Which is usually the only item which will run at the 440) and see how much of a difference in cost between these 3 items ( Transformer, wiring to Mill from mains, and new motor). Most likely the new motor and direct wiring will be less than the transformer. If you do get a specific size ( kva or amps) of transformer you need contact the local electrical supplier and they should be able to get you a quote quickly, Just remember to know the type ( Y or delta, etc).

Mike Aalderink

Re: CNC Mill Transformer
 

-The power rating on the mill is 7kVA.

-It would be really stupid to replace the motors on a $105,000 mill just to get away from buying a $1,500 transformer

-Our sponser was the person who told us that the battery back-up was the transformer

-We are installing the mill next to the room with all the power coming into that wing of the building

-We don't like to just waste money, that is why we are buying the transformer, because it would also be kinda pointless to buy a transformer when we have the power right there

I am not trying to be negative when i say this but everything all of you are saying is common senseexcept for the delta/Y connection or whatever it was we do need to check on that.

I have called a couple places already and we are probaly gonna have a custom transformer made

Re: CNC Mill Transformer
 

You will not find a place to make you a custom transformer for the expense you think. A custom device is extremely expensive.
As to Y and Delta, they refer to the way the power is supplied by a transformer from the power company. A "Y" wound motor cannot be wired to a "delta" output transformer. Many installations use the "Y" which is four wires, three power and one neutral. There are stock transformers available that will do the 208/440 transformation in the 10kVA range that would be suitable. Even at that rating a transformer will run over $1000 and might be up to $2000 delivered and installed. Please contact a local electrical contractor who does these types of installations every day. They will give you a quote and other advice as needed. Hook up the wrong way and your $100K mill is nothing but a precision pile of metal.
Now to the discussion of the backup battery, it is possible that the mill runs on DC and that the battery provides power during a power failure that would otherwise damage a job in progress. It is still possible that the mill has taps internal that would allow it to run on several different voltage inputs. An electrician who specializes in this type of installation would be able to help.
Dude, take the advice and get someone who knows, please.

Re: CNC Mill Transformer
 

well we are getting someone who knows, but a custom trans former wont cost that much, like I said it is gonna be 1500$ and probaly $200 to install it

As for the y/delta we don't know which one it is, that is why we didnt order the transformer yet, also we wouldn't be doing this unless we knew what we are doing first, that is why we are getting advice. Your robotics team doesn't build a robot before they know what it has to do, do they?