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Joined: Oct 2002
Posts: 177
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Member
Quote

Belgian,
Presumably all houses wired this way use the TT earthing system?

Not only 3x230V use TT system. ALL residential and small buisinesses use TT system in Belgian.

Joined: Apr 2002
Posts: 2,527
B
Moderator
Question from the left side of the pond on ratings…is "3x230" 230V ø-ø or ø-n...for 3ø 4-wire?

And, one more time…a TT system is a solidly-grounded at the wye/neutral point of the serving {utility-owned} transformer, right?

Joined: Aug 2001
Posts: 7,520
P
Member
The 3x230V nomenclature is a peculiar (from our perspective) way of specifying that the supply is 3-wire, no neutral provided, with 230V between phases. In other words, it's a 127/220 wye (or 133/230 I suppose, nowadays) system, grounded on the star point but without a neutral distributed to each house. Some parts of Europe did use 127/220 4-wire in the past with 127V appliances.

Yes, TT has a solidly grounded neutral at the supply transformer. But the grounding busbar (and thus the EGCs to the circuits) are grounded only to a local rod. They are not bonded to the neutral in any way, so the sole ground-fault current path is the earth.

John,
I think you're referring to Nikola Tesla, who did a lot of development work on AC machines. He often seems to be the "forgotten pioneer" in some electrical histories.

Joined: Apr 2002
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Moderator
That covers it. Thanks for the details, Paul. I suppose such a setup is a good reason for ELCBs?

Joined: Aug 2001
Posts: 7,520
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Yep -- The TT system results in a high loop impedance, which necessitates the use of an ELCB/RCCB/RCD (or whatever they're calling it this year!) for ground-fault protection.

Joined: Dec 2002
Posts: 1,253
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djk Offline
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JohnS:

The 25Hz systems in use in the US were never used in Europe though. So I don't see how European 50Hz had anything to do with the Niagra Falls system etc? So I doubt it was economy issue.

During the early days of Electricity in Europe the German company, AEG, was the European equivilant of Westinghouse or Edison. It came up with many of the very early DC tram systems. However, there is evidence of AEG 50Hz 3-phase systems very early on. They made a lot of sense for industrial drives etc. By 1920 220/380V 50hz was adopted in Ireland for example and it had been around for a good few years before that.

AEG and Siemens in paticular seem to have developed a huge proportion of the features of the commercial electrical systems used in Europe today.

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25Hz was used during the installation of the 25kV AC railway systems in Britain.

I'm not certain, but I think they may have changed them to 50Hz now.

Joined: Jul 2003
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JohnS Offline OP
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Quote
I think you're referring to Nikola Tesla, who did a lot of development work on AC machines. He often seems to be the "forgotten pioneer" in some electrical histories.


No, it was not Nikola Tesla i was thinking of, it was Karl Steinmetz.

See:
http://www.google.com/search?hl=en&lr=&ie=UTF-8&oe=UTF-8&q=Steinmetz&as_q=%22Alternating+Current%22
http://inventors.about.com/library/inventors/blsteinmetz.htm

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djk Offline
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I doubt any railway company in their right mind would use any AC frequency other than 50Hz in a 50Hz country unless they wanted to either generate all the power themselves and loose the ability to buy it commercially or else spend a fortune on electrical gear to change frequency!

Producing DC's not such a huge problem but with modern variable speed drives etc etc. it doesn't seem to offer any advantage.

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C-H Offline
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Germany, Sweden and a couple of other countries use 16 2/3 Hz for trains.

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