Voltage/frequency converter questions

I'm looking ahead to my eventual move to Australia, which might happen sooner that I really want if things don't pick up around here soon.

I would like to take my whole shop, lock stock and barrel. Started looking into voltage/frequency converters, and saw a post on a message board about driving a 110-220v/60Hz generator with a 220/50Hz motor, using a belt drive to run the generator at proper input rpm. I easily run my 3 phase equipment through a home brew rotary phase converter on a 50 amp circuit. 50 amps, as I can unplug the converter and plug in my MIG welder. The convert has 30 amp slow-blow fuses, and have never popped them. If I got my numbers right, a 12Kw or greater generator should handle this easily, and handle any 110 stuff I'd want to run at the same time. I'd take all my conduit and sub panel (plus some spare breakers) and run circuits for the US stuff, and the normal circuits for anything I add to the menagerie there. Anyone have a good idea what HP 3 phase motor I'll need to locate over there to drive a 12Kw generator?

Now on to the equipment, I could cut back to a smaller generator if I could run the 3 phase machines on 50Hz. Both Hardinge lathes state 60Hz, as does the 5hp motor on my CNC mill. The Bridgeport says 50 and 60hz if I'm reading the stamped tag properly. I'm no electrical engineer, but it doesn't look to me like it would be wise to try and run the other three machines on 50Hz, but I find it curious the BP appears to be rated for it.

Thoughts? Comments?

Btw, my reasons for wanting to take the whole shop is because all this stuff is paid for. In this economy, I'm not going to get near top dollar for it From what I've heard, machinery and tooling is pretty pricey down under. Looking into container shipping, and I'm guessing it's going to be cheaper to ship a working shop that try and find machines there and have them shipped out to a rural town.



Reply to
Jon Anderson
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my recollection from looking around AU a couple of years ago was that tools were expensive, as you suspect - but you might find that motors are not too dear. Further, on many of your tools, you can rewire the motors easily for

220V, the only difference the 50 hz will make is that they will run 5/6 speed and a bit hotter - if you add some cooling (like a fan) to anything that seems to run too hot, then that problem is taken care of - if shaft speed is important, you can adjust pulley size. Or go to 3 phase motors and use small VFDs
Reply to
Bill Noble

If the motors that are not rated for 50Hz run hot, you can reduce the voltage to 50/60 x nameplate voltage with buck transformers. The speed and HP will also drop to 5/6 of the nameplate rating. This is exactly what a basic VFD does, in fact, they're sometimes called V/Hz drives.

If you want the full speed and HP, a properly set up VFD will do it, regardless of the input frequency.

Reply to
Ned Simmons

I don't know about Australia but in the UK tools on building sites have to be 110V for safety reasons and so 240V to 110V transformers are readily available and not particularly expensive. I don't think the universal motors will mind the frequency difference.

Reply to
David Billington

Ned & Bill,

Thanks for the input. Gunner thinks my Omniturn control might run OK on

50hz, and it dawns on me that perhaps my home brew power supply for the CNC mill might work OK too since power is rectified to DC. Certainly, both computer's power supplies can be switched to 220/50Hz.

If I'm going to do anything for power conversion, I thought I might as well go all out so that the many 110v tools I have can be used. Baldor carbide grinder, the Deckel I still hope to obtain, torque limiting power screwdriver, hand drills, power shears, grinders, Dremels, etc. Individually not terribly expensive, but as a whole there is a lot of capability in all these tools that would cost a pretty penny to repurchase over there. And I have a pretty killer shop stereo setup I'd love to take along.... .

Lots to consider, have to start somewhere!


Reply to
Jon Anderson

Hmm ... for the lower powered things, a big autotransformer (or a stepdown isolation transformer). You want one rated for 50 Hz of course, so you might do better getting that in OZ. One option is a big (e.g. 20A or so) 240 V Variac or Powerstat. Most of them have a center tap, so you can wire your outlets between neutral and the center tap and not have to worry about someone spinning the big wheel (knob) and frying what is connected to it. I have seen a kid do precisely this, in an audio facility in an embassy. The load needed to be hooked to the wiper for that use, because the line voltage was rather untrustworthy. You might wire a second outlet, with a cover painted bright red, to the wiper soyou can test equipment at lower or higher voltages.

Good Luck, DoN.

Reply to
DoN. Nichols

I am dubious it pays to ship big heavy motors, vice buying ones there; but you can do your own figuring there.

If the motors are rated 50/60; they'll run on 50Hz. If not, rotsaruck. Running a motor underspeed decreases its counter-EMF, ergo increases its current draw.

I'd be thinking of a VFD. It can get you 60 Hz easily. I don't know how much single-phase load they'll take, but my SWAG is a good % of their rating.

Any motors with brushes, i.e. electric drills, hand grinders, won't care.

Switcher supplies won't care. Wall-warts {with transformer/rectifiers} WILL care but may survive on 50 hz. The most marginal will croak in minutes, the others may overheat badly. [I have a larger one - 3"x5"tallx3" deep. It was in a 50 hz location and melted. It went from:

----- | | | |-- stuff is paid for. In this economy, I'm not going to get near top dollar

And the import taxes on same?

Reply to
David Lesher

Well, load capacity of a 20' container is approx 20,000 lbs. Volume-wise I can't get everything into a 20'r so would have to use either 2 20's or a 40'. I know actual weight has a lot to do with shipping costs, but the cost of throwing in a couple motors is insignificant compared to the overall cost. If I decide to build a 50Hz run voltage/freq generator though, I'd get dims for a suitable motor, build the unit here, and buy the motor there.

Still have lots to research, but my understanding at the moment is that if I'm bringing in as my own personal possessions with intent to do business, or just a well set up hobbyist, I don't have to pay VAT. However I understand selling machines within a year or two of moving there could incur a VAT assessment.


Reply to
Jon Anderson

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