Had posted this in s.e.design but was told that this is a much better place to ask. The main reason is that I've heard some horror stories from Australians about line voltages shooting up to 270V, UPSes blowing up and so on, but this was more inland.
A product is going to be test marketed in Australia, northern half of the east coast. We know the line voltage there is 240V/50Hz but not which tolerances apply. The upper limit is important to us, and also whether it tends to exceed whatever the standard might say. Can someone elucidate?
The line voltages at my place (Sydney, north west, Hills area) are
257.3V, 259.4V, and 257.8V, at 2:10pm today. They do go higher at night. The are about to bring a new substation on line. That may improve the voltages.
Energy Australia (our local network provider), have a nominal tolerance of 240+/- 6%, but allow it to vary from 216V to 264V active to neutral.
**Ask an Australian manufacturer of similar equipment, or source your transformer/s from an Australian transformer manufacturer. They're well aware of the local conditions and seem to manage quite well. That said, except for Perth, most of the major cities in Australia have quite respectable mains Voltage tolerances. IME, the biggest problem with US-sourced equipment is that transformer manufacturers in the US appear to have no idea that Australia operates on 50Hz, rather than 60Hz. The resulting crappy transformers perform very poorly indeed. Mind you: Bad as some US transformers may be, Chinese ones can be worse.
But the 257.8V measured by David near Sydney sounds quite scary. That's
+7.4% right there, a lot more than they allow even in the UK. 216V-264V sounds even more scary.
We are in contact with the mfg and trying to arrive at a transformer design that can take 50Hz and the required max voltage without too much in core saturation. But at the same time we need to have enough minimum output at the lowest expected voltage because there is a buck converter at the other end. I wish there was a SEPIC instead.
To make matters worse, we are size-limited with the thing.
Electric motors are another issue, they really don't like undervoltage operation. But they will most likely be sourced in Australia.
** The only thing you need to control is the final temperature of the windings when in use - and that depends on the ambient temp, among other things.
Northern Queensland get VERY hot and has very high humidity too.
When you get sample 240 volt transformers to try, apply full secondary loading and run them at 265 x 60/50 = 318 volts AC at 60 Hz. This will create the same primary magnetising current as 265 volts at 50Hz.
The temp rise of the primary needs to be no more than 50 degrees C.
Be aware of using thermal fuses with too low a temp rating.
I have a jig here where I can dial in the frequency, for testing stuff at 50, 60 and 400 Hertz.
The 50C will be a challenge because we are constrained in transformer size (to what they have in there now). Luckily we only need about 70% of its current VA-rating.
And what out for them Northern Queenslanders. After what you said in the other post they'll watch ya. "Oh, look, I think that's him!" :-)
Says _current_ transformer up there, meaning the one we use right now, for US only. Simply using an international version of that one will cook itself out of the board at 264V. I've tried that.
Ah, now there's a convincing argument if ever I saw one.
Being an E.E. living here for 55 years, (and I doubt that you are, Trevor) I can honestly say that Perth isn't any worse than the other Aus states I have spent time in. Rural is another story, with SWER systems being problematic anywhere.
A lot of this myth about Perth (and W.A.) originates from the fact that while ROA had a nominal 240V system, we had a 254V supply until late 20th century. (Actually it was not defined as single phase but as
440V phase-phase, 254 being the derived number). This grid voltage selection originated when supply changed from 40Hz to 50Hz, to allow existing plant to continue in service with minimum performance loss.
And that the facts as I remeber them too. Having worked for a nation wide computer company in those years we had to consider the different voltage in the west when specifying machines.
**You asked for the facts. I stated them.
**Again: It's not a belief. Back in the 1970s, I was service manager for a hi fi importer. I noticed that service agents in WA (mostly Perth) ordered far more parts than could be substantiated by the numbers of products in the state, compared to all the other states. I questioned a couple of service agents and they explained that mains Voltages were generally considerably higher than 240VAC, for considerable periods. Thus failure rates were higher. Since that time, I've maintained close connection with various distributors around the country. Most report more problems (per number of units sold) in WA than any other state.
No, that's not what he asked, he asked "Why do you believe that Perth has noticeably worse voltage tolerance."
And facts? Your smart-arsed answer showed you really don't know. (So what else is new?)
Bloody Hell!!! You're a dill! You're talking almost forty years ago...
*At that time*, Perth's nominal voltage was officially 254VAC and no secret was made of that. Almost always, the mains were higher than 240 V. Most Australian manufacturers, particularly of TV sets, had a 254 V (or 250 V) mains input setting. If importers distributed under-rated equipment to a market at odds with that market's then fully published standards, that's surely their problem. It progresses now throughout Australia with Seppo equipment at 220 or 230 volt 60Hz. Transformers very often do not have enough iron for use at
230/240 V 50 Hz, with consequently larger than normal failure rates. (Switch mode PS had alleviated that a bit, of course.)
Bullshit. Your word, more than anyone else's in this group, is completely suspect. Most of your postings demonstrate that. Put up some proof or go back in your hole and shut up with the lies!
For almost two decades, Perth has had the same nominal voltage and tolerance specs as the other states. Yet you continue to live in the past.
BTW, I understand BHP (Billiton), either until very recently or still, are using 254 VAC (440V phase to phase) as their nominal on-site low power voltage.
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