Distibution Transformer Explosions

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Heres a site you may like
**broken link removed**
 
Rodalco

I appreciate that the connection shown is quite correct under normal circumstances.
What worried me was the common earth return wire for the 11kV and the 230/460v.

If there is a fault (O/C) on that wire, the user supply and its earth is floating at 11kV.

JimB
 
It is usually used in MEN installations, which will be earthed at the switchboard as well.

I can see your point, that when the neutral/earth breaks a potential problem may occur in that case.

In New Zealand we keep the HV earth separated from the LV earth at the supply transformer point.

The photo in question was from a lighthouse in Iceland , perhaps earthing was difficult there, on the rocks so a common point was used for earthing.
 
I'm more interested in seeing what's inside those metal cans.

Does anyone have any pictures of transformers dissected?
 
Pretty much the same thing you'll find in any transformer, wire and insulation, just more, and bigger.
 
Why do you suppose they use flat copper strap in there? Low impedance or just easier to bolt to the lug?
 
i think it's because you can bolt it easy, you can't bolt round wire easily. you can't use solder due to the temperatures, so they bolt it. that's what i think anyway.
 
I've peeked into the recitfiers (1-20kw) we have at work (some junk) and they're all wound that way. I'm asuming it's just about everything, including increased capacitance I mean it's the same way a rolled capacitor is constructed. If you notice it's not just the ends that are ribbon, the transformer windings themselves are ribbon.
 
Flat conductors waste less space on the bobbin, and maintain flexibility even when the cross section is large (they just get wider). You can wind bare copper and insulate with a membrane (paper?) And if you choose your thickness carefully, you can eliminate skin effect. Try to bend an insulated large diameter wire, in a tight radius, and the insulation just cracks.

You'll see flat conductors in the high current windings of switching power supplies.
 
I've also seen many thinner copper enameled strands paralleled to form a ribbon, I imagine that this eliminates the skin effect even more.
 
I was on holiday in Cornwall last week and the back of our bungalow had some nice hardware visible

I couldn't resist getting you lot a couple of pics.

**broken link removed**
**broken link removed**
 
thanks for the pics!!! it would be kinda fun to have a walk around in there, and hear all the big blocks of metal humming!
 
things said:
thanks for the pics!!! it would be kinda fun to have a walk around in there, and hear all the big blocks of metal humming!
Click to expand...
Sounds sad but it was actually quite interesting lmao

When it rained or was humid you could really hear the humming and hissing and at peak electricity usage times it was quite noisey as well.
 
Hey Guys cool thread.


My father used to work at a place where they made these huge transformers in the UK.
BIG ones.


One time one of the transformers kept arcing failing its initial power tests.

After plenty of head scratching they drained the oil out to find a set of metal stepladders in the space between the coils...
 
hahaha a step ladder!?!?!?!? how could you leave that in there????? that must have been a MASSIVE transformer!
 
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