Questions about power pole "devices"

Your going to need to post links to pictures. You descriptions are very lacking. Also, there is a newsgroup just for electric utilities: misc.industry.utilities.electric

Charles Perry P.E.

Fiber-span expansion joints... nothing to do with "power".

--s falke

I have not a clue what your trying to describe here.

If I understand correctly these are the links that continue the power in modular furnature. Usually at the bottom. The stuff I am speaking of has the outlets on the bottom of the panels. I have seen brown, chrome, and black, depends on the manufacture and product line.

Again not a clue what your trying to describe.

i would contact the public relations department of your local utility co. explain to them what you are doing and perhaps show then your shots. they may then call in an engineer or field service to meet with you.

there are some good books on this dude, go look it up

excellent, "fiber-span expansion joints"!

Cheers,

-sd

weird I don't have that on my news servers..thanks anyway though..i'll check google groups.

Cheers,

-sd

Thanks folks.

I think the electric dept. idea is the best one yet.

Cheers,

-sd

Next time you see a bucket crew working on the street bring them coffee and doughnuts. While you are snacking, pick their brain.

----- Original Message ----- From: "Some Dude" Newsgroups: alt.engineering.electrical Sent: Monday, July 19, 2004 11:22 AM Subject: Questions about power pole "devices"

I'm thinking maybe dampeners put there to take some of the vibration out.

These are insulators that are placed between the energized line and the (most often grounded) pole. They are ceramic and glass types because of their excellant insulating capabilities.

I haven't a clue...this may be lower than the actual electric lines and is probably a phone line of some sort. Good Luck... if you are for real pal. sincerely, an old clumsome

If you mean 'loops' where the wire is connected to the insulator, these are sometimes used on HV lines to control the electric field strength. The small/sharp edges of bolts/nuts/fittings can cause a very intense localized electric field. It can be high enough to actually ionize the air near it and cause a lot of corona discharge/losses. If the small/sharp edges are surrounded on all sides by an larger area of the same potential (the wire 'loop'), then the voltage gradient right at the fittings is zero and the gradient at the much larger sized loop is low enough to limit corona.

Can't quite picture what you're describing here, sorry.

The problem is that the length of the span is such that its natural frequency is too close to that of the frequencies produced from vortex shedding. So when the wind blows, the wire will begin oscillating excessively. This causes fatigue failure where it is connected at the insulators. Putting a 'dead weight' on the wire, changes the natural frequency so it no longer resonates with the wind vortices and the line is much more stable. These weights are often a length of small al/steel 'i-beam' (just 4-6 inch across) about a foot or two in length. Is this what you're seeing?

daestrom

Thanks for all the attempts to answer my questions. I did a poor job of describing these various devices. I will post a URL to these images and perhaps people could advise me better.

Thanks again

Cheers,

-sd

Don't let the Homeland Security folks catch you snapping pictures of utility equipment or they might think you're trying to sabotage it.