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#179660 07/25/08 08:42 PM
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I just wanted to say just what a pain in the ass it is to deal with Japanese 50 and 60Hz power when you have 6 or more service entries to a building, each of which feature a different voltage, phase and frequency combination. Whole different design philosophy over there. Makes adding a generator fun.

Edit: you know... I wonder what power their toilet seats take? I didn't think to look. GFCI, I hope. Damn, wouldn't THAT be a terrible way to go...

Last edited by SteveFehr; 07/25/08 08:44 PM.
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I remember hearing a story some years ago about a death-row prisoner (don't quote me, but I think it was in South Carolina) who had his sentence commuted to life imprisonment. He was later electrocuted accidentally fiddling with a portable TV in his cell while sitting on the steel toilet. I guess sometimes destiny just won't be cheated.

One nice thing about the mixed 50/60Hz in Japan though -- All those Sony tape decks with AC motors which can be converted by just a simple internal adjustment. Makes it easy to move them between the U.S. and the U.K. smile

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I wasn't aware that different frequencies were in the same street, are you sure?

My understanding always was that certain parts of the country run at 50 Hertz and other parts at 60 Hertz.

Double frequencies in one building means also double sets of powerlines in the same street which doesn't make sense.

The voltages yes, that can be 100, 110 or 120 Volts depending what tap the local transformer is set at.

My question, What are the Japanese 3 phase voltages ? 110/208 Volts , 277/480 Volts ? just interested to know.

The Sony or Akai tape recorders: They are dual frequency, either altered by a switch, belt on different pulleys or sleeve on the capstan for Reel to reel tape recorders.
These cover all voltages 100, 110, 120, 145, 220 and 240 Volts


The product of rotation, excitation and flux produces electricty.
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Okay i gotta ask why the difference in Hz?

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Originally Posted by RODALCO
The Sony or Akai tape recorders: They are dual frequency, either altered by a switch, belt on different pulleys or sleeve on the capstan for Reel to reel tape recorders.
These cover all voltages 100, 110, 120, 145, 220 and 240 Volts


Yep, that's nice that they cover just about all possibilities. I have an Akai 4000D sitting here right now. smile

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Why?
1. As far as I'm informed they have 50Hz in the East and 60Hz in the West. So there is no dual frequency in one building.

2. As far as I goggled this split is based on post world war 2 reconstruction done by the US in the West and Brits in the East ????? at a time when national power grids were not yet state of the art.

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http://en.wikipedia.org/wiki/Utility_frequency

This link gives a good overall idea of mains frequencies.

I thought so, thanks for confirming that Wolfgang. It would be very expensive to duplicate a power supply system to cope with 2 frequencies in one street.


The product of rotation, excitation and flux produces electricty.
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Originally Posted by RODALCO
...My question, What are the Japanese 3 phase voltages ? 110/208 Volts , 277/480 Volts ? just interested to know.
...

[Linked Image from upload.wikimedia.org]
Electricity distribution(Japanese) |Translate via translate.google.com or babelfish.yahoo.com

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Dear Rodalco,

following cn_HK's link you drop on a Japanese page which offers in the lower middle five links:
1.
http://ja.wikipedia.org/wiki/%E4%B8%89%E7%9B%B84%E7%B7%9A%E5%BC%8F
2.
http://ja.wikipedia.org/wiki/%E4%B8%89%E7%9B%B83%E7%B7%9A%E5%BC%8F
3.
http://ja.wikipedia.org/wiki/%E9%9B%BB%E7%81%AF%E3%83%BB%E5%8B%95%E5%8A%9B%E5%85%B1%E7%94%A8%E4%B8%89%E7%9B%B84%E7%B7%9A%E5%BC%8F
4.
http://ja.wikipedia.org/wiki/%E5%8D%98%E7%9B%B83%E7%B7%9A%E5%BC%8F
5.
http://ja.wikipedia.org/wiki/%E5%8D%98%E7%9B%B82%E7%B7%9A%E5%BC%8F

Hoping you're able to decode the pages you might discover different schemes that make me suppose that the Japanese make a difference between residential and industrial wiring, the latter being installed in 415/240V and then still compatible to a IEC TN System.

In residential installation all of the four other sketches show sort of US inspired single phase or delta constructions with 200V phase to phase. The 100V for domestic stuff is obviously always generated by a centre tap, except for trannies that offer 100V single phase only.
As delta trannies do not offer a second voltage unlike a Y, other voltages are probably not available.

But, this is pure speculation as my knowledge of Japanese equals zero.

What irritates me furthermore is the fact that many links say that there are almost no grounded outlets (sockets) in Japan.

I'd like to know more about that.

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Thanks for all that info guys.

It looks mostly like the split phase system 100 / 200 Volts with centre tap.

I will ask a good friend of mine who travels to Japan for work twice a year to take some photo's from a kWh meter and power socket and get some data from locals with a bit of luck.


The product of rotation, excitation and flux produces electricty.
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