240V 3ph to 220V machine? Coolant pref?

[ThatguyDave]

Good afternoon. Some months back I purchased a 1997 Daewoo 8S and I'm finally getting the opportunity to get it set up and under power in Philadelphia. Along with a 1996 Fadal 4020, this is my first CNC so I would really appreciate some insight on a few matters.

The building is wired for a 240V 3 phase delta service, ie one center grounded 240V transformer supplying two 120V single phases, that combine to one of the 3ph 240 legs, and a second transformer supplies a high 208 leg whose potential to either side of the first transformer's output is also 240V. The high leg in my particular area is a bit high, 213V and another leg is sometimes a bit low so on at least one occasion I measured voltage as high as 247V coming into the building. Granted this voltage will drop somewhat as it travels 125+ ft to my circuit box and another 30 ft to the machine.

As such the 240V might be slightly more than 10percent higher than the 220V the machine was specified to run on. My electrician doesn't think this will be an issue but searches of past posts here show that at least some would disagree.

The machine has a Mitsu Melda 520L control. Unfortunately the machine/control manuals don't seem address voltage requirements in much detail.

Do I need an autotranformer to comfortably run this machine?

Additionally, what coolants would you recommend. The machines will be doing alot of all around work ranging from SS, to tool steel, with plenty of aluminum thrown in for good measure. Its mind boggling with all the coolants that are available. I can't even decide on a type of coolant let along an individual mfg.

Thanks again for the advice. Dave

[Bill Sergent]

Dave ,

We have seven Daewoo Lathes , all of them are 220 volt machines. The controls are all Fanuc. We are located in San Diego , Ca. the power in our area is 240 Delta. When we moved to our new location we had San Diego Gas and Electric install a device to record the voltage highs and lows throughout the day. We found that the power varied between 220 volts and 260 volts . We contacted Daewoo and Fanuc and gave them the information and both of them advised us to install transformers on all of our machines . Fanuc indicated that they have hade machines in the field with their controls that have lasted 10 years on 240 Delta , but have had new machines that have smoked the controls and servos in the first ten minutes of operation. Daewoo advised us to install transformers on all of the machines also. In our case the transformers are cheap insurance , and have provided 10 years of service with no issues . All of our transformers are 45 KVA energy star. 240 V Delta to 208 V 3 Phase.

Bill Sergent

Hi Performance Machine & Metals Inc.
619 448 8802

[ThatguyDave]

Thanks for the heads up Bill. 220V-260V is a pretty big swing. I'll probably go for the step down transformer but I'm guessing that the 240V delta service in my area wouldn't hurt the machine. I may disconect the servos and control and hook it up to line current and see how much higher the control current is than the 100V its specified at. I've always been told having low voltage is a much more detrimental than high voltage because running on low voltage, a motor must pull too much amperage causing it to overheat.