ECN Forum Forums General Topics of the Trade General Discussion Area choke on this

I have a picture that is perfect for this thread , But I am too new to figure out how to add it to the conversation

Togol, if you email it to me, I can host'n'post it for you. You can find my email address by clicking on the icon on my post.

Ok Larry, ... I just did !

We would prefer to put pictures up that are loaded on the ECN servers. That way they don't get "lost" in the future.

Please e-mail them to me, another of the moderators, or e-mail them to webmaster@electrical-contractor.net

Thanks

[This message has been edited by electure (edited 10-20-2005).]

......ok,
it should be in your mail box

Here are togol's pics
He can explain what's happened here






Thanks, guys!

Thanks electure
well , these are examples of separate phases in individual raceways, there is an aluminum bus supported inside of the Aluminum pipes . referred to as Iso-Phase.
these were running at 13.8KV.
Incidentally ,this unit is adjacent to the unit that experienced some....electrical problems ....
Those are in the Photos folder ....titled ***FIRE***

togol

IIRC, aluminum has no magnetic properties, so you shouldn't get any inductive heating of the aluminum conduits.

Even though aluminium is not ferromagnetic, you will still see magnetic flux in the space between the conductors, and thus current flow induced in the enclosing conduit. The flux is stronger when the conduit is ferromagnetic; think 'iron core transformer versus air core transformer'. Clearly the separate conduit approach works; I'm curious as to the details of the engineering to prevent inductive heating.

I encountered this sort of conduit on a tour of the 'Glen Canyon Dam'. This was a standard open tour group, not some sort of special event. At one point the walkway has a very good view of the distribution transformers. Google images found this photo:

You can't see it in the above image, but at the end of the row of transformers (the side nearest to the viewing area), the ductwork is vertical; three _large_ pipes side by side. There was a horizontal rail near the ductwork.

Someone had arranged what appeared to be a coffee can, inverted and free to spin on a spindle, just sitting on the horizontal rail near the ductwork. The can was spinning merrily away. I believe that the can was essentially the rotor of an air core induction motor with two half turn stator windings. I suppose that it could have been wind, but I don't recall much wind at the time, and the can was smooth, so the wind should not have caused any torque.

-Jon

(edited to add image to ECN server)

[This message has been edited by electure (edited 10-22-2005).]

It seems to me that the bus arrrangement inside the "conduit", was comprised of four separate flat bars that were welded into a box shape, the sections were coupled together with flex links .and then the joint was covered and seam welded !

I recall tthe final connections on the transformer taking three days to complete,

togol