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Joined: Dec 2009
Posts: 23
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A bit more has occurred to me, although I'm sure the original poster has already solved or cancelled this problem...

Remembering from my time in small electronics repair:

1. 90% of the stuff we get in the USA was originally designed overseas. Most of the world uses 230/240, so everything is designed for that and then modified to work here. Sometimes the modification consists of specifying a completely different transformer for the US version. Often, however, the power supply transformer simply has different primary taps for different supply voltages. It may be possible to turn the US version of the oven into the UK version simply by moving a jumper wire on the board.

2. Regarding line frequency: The most popular clock/timer IC (don't know a specific number off-hand, as there are like 30 billion different versions of it, mostly pin-compatible, and all function-compatible.) has a logic pin that selects 50/60Hz. I'm sure this exact IC isn't used in the oven (as the oven needs other functions said chip wouldn't provide, requiring a seperate µC, and it makes much more sense for the clock to be integrated in the firmware), but there still may be similar.

Joined: Mar 2005
Posts: 1,803
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I bet they still think they 'saved money', even with tripping over all those cash-sucking transformers parked all over the house! Jeez, the mind boggles! laugh


Wood work but can't!
Joined: Dec 2001
Posts: 2,498
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Well when I had a field day with a spark at age 14 he told me a story of an American who had his whole house in Austria built as close to US specs as he could - including a huge transformer, probably 400V single phase primary and 120/240V secondary. I'd still love to know where on earth he got his light bulbs from... and what the building officials had to say about it (at least nowadays larger work that requires a construction permit and includes any wiring requires a full certificate of compliance including all kinds of measurements (isolation values, loop impedance, yadda, yadda, yadda) signed by the EC who did the work and can be held responsible in case of an accident).

Joined: Jul 2002
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Ragnar,
It's funny where some of these "out-of town" installations show up.
I remember well a friend of my late Grand-father who he'd met in Italy during WWII, who hailed from Wisconson in the US, but had come out to NZ on a fishing trip after the war ended and liked the place so much, he built pretty much a 2nd home here and used to travel backwards and forwards, to avoid the US winters.

This guy also had a job with Operation Deep Freeze (the base of the US in Antarctica), so it wasn't that much a holiday home as much a base to drive to his work in Christchurch.

I had a look around his house, during a visit there after the funeral of my Grand-father and it had a 400V 3Ø transformer and the secondary side was 120/240V.
I think (from memory), he had a Cutler-Hammer panel and at the time it was the biggest panel I'd ever seen in a house here.
All of the cables, switch-gear, recepts, switches and the like were all imported from the US.
The house was built in 1957.

The one thing I could not get over was the size of the wires where they went into the house, being all over-head at the time, the PoCo had stipulated that the installation from the secondary side of the transformer had to have single cores run to the building, via huge insulators on the pole end and heavy pin-type insulators at the house end, driven into solid rimu timber, as opposed to something like is currently used in the US.

Oddly enough, the metering was all done on the 400V side of the transformer, as there was no way that our regulations would have allowed a US type meter here.

That particular regulation died a death in the 1961 regs.
I'm sure Bob enjoyed not having to pay for the hysteresis current of that transformer. wink

I've never forgotten that huge box out on the pole that had the metering, C/T's and a big red label stating:
Quote
This installation uses non-standard voltages and wiring configurations on the secondary side of this transformer, please check the plans within this enclosure.


With regard to fittings, at the time, I never knew that you guys in the US had your switches up-side down. grin

As far as I am aware, I think that the place used Arrow-Hart switches and recepts.
Back in 1957, there were a lot of houses that never had isolators on the recepts, even the local ones, so I guess that would have helped the inspection process.

The guy imported all of his own appliances, which back then wouldn't have worried too much about the difference in frequency, let's face it, washing machines (as basic as they were back then) would run slower, but it was no big deal.

Everything these days seems to have a motor on it for something, take for instance, the oven in the original post here, fan ovens haven't been around that long, but they are more of a convenience thing, than anything else.
An oven will work just fine without it's fan, it just takes longer to cook/bake something.

Bob passed away 7 years ago and I got an e-mail from his son to direct me to start taking the electrical side of the building to bits.
It wasn't a fun job, although the wiring was as neat as, it was like this is something that should be photographed, because one of these installs in New Zealand would be pretty rare.

Un-fortunately, I didn't own a digital camera at the time and pretty much when I got there, the builders had ripped most of the walls down (damaging the wiring in the process) and the PoCo had taken the distribution gear.
That really annoyed me.
A once in a life-time thing, gone. cry





Joined: Dec 2001
Posts: 2,498
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I assume that guy had the metering on the primary as well - after all the PoCo wants to use their own meters and they most definitely won't supply a 120/240V 3w meter.

The US facilities in Germany have extensive 120/240V systems, but as far as I know they mostly use German switches and German-made NEMA receptacles that fit German boxes. Supposedly I can get my hands onto some of those next spring, definitely going to post pictures then!

Earlier this year I saw a house in Austria (near Vienna) where I suspected 120/240V wiring too. The whole place was just so incredibly American in style, it was hard to believe. Like a miniature version of the Capitol with some brick thrown in.
Here you go (just linked since it's really OT and I already had it uploaded to my Photobucket account)
https://i17.photobucket.com/albums/b82/W_e_St/Bisamberg/P2240042.jpg

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