help with buying a machine in usa

[greg b]

hi everyone

im thinking of buying a cnc lathe (bridgeport/ cincinatti/ hitachi seki) within the usa. i believe the voltage there is 230 volt 3 phrase 60hz. over in australia its 415volt 50hz. could someone tell me if these machines have a inbuilt system in there electrical cabinet that u can change the settings to accomodate our power usage

thanks guys

[HuFlungDung]

It would depend on the specific machine. It is also possible that an American machine could be set up for 440v or 550v, so a general opinion really means very little.
Worst case, I suppose you could get a transformer on your end, to adapt from whatever to whatever voltage.

As for the change from 60hz to 50hz, I don't know of many instances where this could cause a problem except maybe electric wall clocks. However, you will get 20% less done in a day on 50hz

[Geof]

Originally Posted by HuFlungDung .....as for the change from 60hz to 50hz, I don't know of many instances where this could cause a problem except maybe electric wall clocks. However, you will get 20% less done in a day on 50hz

Perhaps I can confirm further my reputation for being nit picky.

When you go from 60hz down to 50hz you go 16% slower; when you go from 50hz up to 60hz you go 20% faster. So it is 16% less.

Trivial point? I don't think so; what about if you were calculating a pulley size change to compensate for the change in rpm on a motor.

[DSL PWR]

On most modern machines all you should have to worry about is the voltage, as most rectify the voltage to dc, or run thru a vfd. Most modern controls and drives can handle 50 or 60 hz.

Don't take this as gospel, and check with the manuals of the machine you want!

[HuFlungDung]

Originally Posted by Geof Perhaps I can confirm further my reputation for being nit picky. When you go from 60hz down to 50hz you go 16% slower; when you go from 50hz up to 60hz you go 20% faster. So it is 16% less. Trivial point? I don't think so; what about if you were calculating a pulley size change to compensate for the change in rpm on a motor.

I'd go for a motor pulley that was 120% of the original pulley diameter (to get rated rpm output on the American machine), or if that wouldn't fit, then a driven pulley 83% of the original pulley diameter. Good point to bring up though

[Geof]

Probably the only motor(s) on the machine that will run slow are the coolant pump and possibly the cooling fans, but on some machines I think the cooling fans are driven from the DC bus.

Hu; the picky point about percentage change depending on whether your are calculating up or down can cost you in some circumstances: Imagine you had investments that dropped 20%, you start to worry and then they come back 20% so you quickly sell them to break even (?????). It is an error that is so easy to make with a quick mental calculation

[greg b]

Thanks guys for the reply,the real problem i was conserned about was the 50/60/z on the computor side of things.that it might damage the controll.But after some more investigation it appears some machines within america have dual tap transformers already desighned into them brigeport/cicinatti being some of them.Im sure there are other brands out there but without reading the manuals its a bit hard to find out.

[Geof]

The 50/60 thing is irrelevant to computer power supplies because they can handle both these days.

You should look deeper into the built in dual tap transformers; many machines do have multi-tap internal transformers but these work in the 208 to 240 volt range because across Norht America you can get this variation. You will most likely need an external 415 to 230 volt transformer.