[R-390] OT - Transmission lines - local

[Les Locklear]

Interesting story about 4160 volts.

Several years ago when I was still an electronic controls technician for 
the government at Keesler AFB, we had a couple of chiller plants that 
had 4160 running to the chiller control panels and then was stepped down 
to 120. We would always caution the new airmen not to carry a voltmeter 
into the switchboard area as they might be fooled into thinking they 
would do a "simple" voltage check. One did one time and that fluke 
destroyed itself and burned him too. We would call out the line crew and 
let them check the 4160 fuse panels with their rubber and leather gloves 
and the buck roger ray gun  that indicated voltage. It was usually one 
leg down and we couldn't get good readings inside our control panels. We 
never messed with that stuff. We worked up to 660 volts, nothing higher, 
that's what they were for. Nasty stuff!

Les
----- Original Message ----- 
From: "rbethman" <rbethman at comcast.net>
To: "R-390-List" <R-390 at mailman.qth.net>
Sent: Thursday, February 24, 2011 1:43 PM
Subject: [R-390] OT - Transmission lines - local


> This changeover began a couple of decades ago.  It used to be that
> "local" lines carried 4160/2400 in a "Y" configuration.  Delta was
> provided for commercial locations that had 3 phase requirements as 
> needed.
>
> Then there began a "feeder" by "feeder" transition to 12470/7200.
>
> The conductors were NOT changed, but by tying a second insulator in
> series with the original single, they would change out the pole top
> transformer.  As they did this, they began the path to the increased
> voltage supplied to residential customers.
>
> One thing I was involved in while still in Uncle Sam's employ, was to
> perform annual Infrared scanning of these systems.  Uncle got "smart"
> and figured out it was a whole LOT cheaper to locate problem areas by
> locating the connections that were WELL over the "normal" temperature 
> of
> the "system".  It has saved a LARGE amount of $$$ to have these 
> problem
> spots noted, and let them schedule the required maintenance in lieu of
> the damaged/destroyed equipment, outages, and over-time paid to their 
> crews.
>
> Finally, my "local" municipality has acquired such equipment.  They 
> have
> been contracting it out.  I've offered to go along with them when they
> begin on their own, but haven't heard back.
>
> Oh well, their loss!
>
> Bob - N0DGN
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