Electric Service / Power for VF3 & SL20

[usjess]

Hi all,

Expecting to re-configure my shop from manual hobby to CNC commercial soon, via the purchase of an older VF3 (mid 90's) and used SL20.

Of course, after I'm wildly successful later on, I'd like to add more and / or bigger machines.

I've been running on rotary phase converter, but my local power company says they will install 3 phase for free. I'll have to pay for the meter base, wiring in my shop, and cut quite a few trees down, if I go this route.

I guess Phase Perfect would be another possibility, though kind of high up-front cost. I'd rather not run these machines on a rotary phase converter, if I can help it.

So, I'm leaning towards that power company solution of actual 3 phase - but, how to spec it? The machines are the usual 200-260 volts or so input (IIRC). I guess my options from the power company are 480 volts, 240 volts or 208 volts. If I go 480 (which I would kind of like) I'd have to buy transformer(s) to run the VF3 and SL20.

Any advice on the +/- of the various voltages available? If I decide to go with the 480 volts supply, is Haas a good place to buy the transformers?

Thanks for any help.

Jess

[JoBwan]

usjess,
Where I work at, we converted to 480 (3 ph) about 5 years ago. Before the 480 vac, we had 208 vac (3 ph). Keep your eyes on eBay for busways, buss plugs, transformers.
It may even be beneficial if you have a friendly electrician that you can pay (as a consultant) to help specify what you need.

Ex: Startup and future expectations of company growth. What amperage. What applications will need to be to local codes. Specific KVA transformers to drop down to 208 bussways and plugs. Making sure of proper series # for buss systems. Adding supressors for "clean" power. Yes, "there is a lot to ponder".

It may seem costly up front, but your electric will be much cheaper and it will pay itself off in no time. Also, think of the maintenance repairs that you will save on machine and your facility by having a cleaner power. Just my $.02. Good luck!!

[gizmo_454]

First off, I would not go without the 3 phase power. As jobwan said, your electric bill will be much cheaper. As for 480, 240, or 208, that is all up to you and what you want to do. Just remember, the lower the voltage you go, the more amps you will pull. The more amps you pull, the larger the main lines from the pole have to be not to mention the ones running to the machines. We have 480 at our shop. Then we run a 30 KVA 480V to 208V transformer. The transformer runs all of our 110, and our Mini Mill. Our SL-10 runs directly from the 480V with the factory installed transformer. The internal transformer would be my first choice if at all possible.

As for buying a transformer from Haas, it's six of one, half-dozen of another. They seem to be a bit more pricey than buying elsewhere. To give you an idea, they want about $1400 for a 15KVA external transformer and we bought our 30 KVA for about that or less. (Its been a couple of years so I don't remember dollar for dollar what we paid for it, but it was close.) I have recently seen some 15 & 30 KVA transformers go at auction for a couple hundred dollars, so if you keep your eyes peeled, you may be able to find a good deal on a used one.

Anyway, I hope this was at least a little helpful for you.

Gizmo

[swain]

I have both the vf3 and sl20 bb running in a 480 shop. I had to buy a transformer to drop
down to 240 3 phase. The option from haas is mounted on back of machine and is unsightly. I moved from a shop with 208....and the multiple problems we had make me never want to work around 208 again.

240 3 phase is my vote..!

[gar]

080411-2237 EST USA

Do a calculation on wire cost vs transformers.

I would favor a 240 delta with a wild leg. This has one pole transformer center tapped with the center tap the nuetral. This gives you your 120-0-120 single phase supply from the center tapped secondary, and the delta is the 3 phase supply. This is often times done with two pole transformers forming what is called an open delta.

The power company may prefer this approach because they may retain your current transformer, and just add one transformer.

.

[usjess]

Hi Guys,

Thanks much for all the helpful inputs and suggestions.

If a fellow decided to spec 480v, is 480v Y the preferred configuration?

gar - does the wild leg / 240 delta have any potential downside when running this type of equipment?

[gar]

080413-0617 EST USA

usjess:

We have 5 HAAS machines, 2 manual mills, 2 manual lathes, 3 saws, 2 welders, air conditioners, computers, and all 120 circuits on a 240 delta with wild leg supply. Additionally there are others in the same building running off of the same pole transformers. There is one large transformer for the single phase stuff, and a somewhat smaller transformer for the wild leg. Our feed line from the pole is about 250 ft.

I do not see a down side unless you want 480. In fact there is an upside because you do not need a step down transformer at each HAAS machine.

If you are in a plant that occupies a quarter sq-mile with a lot of standard induction motor loads, then you want 480.

I think there is an advantage to 240/120 with a wild leg vs 208/120, both are non floating, but 240 vs 208 is probably more suitable for high current single phase loads, such as welders or heaters, DeWalt radial arm saws, some lamps, etc.

.

[slatern44]

I have the 240 open delta system for my shop and so far its been fine. I have 3 Haas mills and all the manual equipment to go along with them. BUT now I purchased a Japanese brand mill and I have to step the power down by using two buck boost so I can get 210 power instead of 243. The Japanese mill want 200-220 power or you will burn up the electronics. So if you stay with USA machines its easy but Japan and German machines need to be stepped down.