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Re: Vegas pole pigs can't take the heat (fwd)

---------- Forwarded message ----------
Date: Sat, 07 Jul 2007 21:15:09 +0000
From: David Rieben <drieben@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Cc: drieben@xxxxxxxxxxx
Subject: Re: Vegas pole pigs can't take the heat (fwd)

Hi guys,

Wow, I got more info than I expected from this question ;^) Thanks to 
everyone for their most informative inputs and thanks to Chip for his
latitude of tolerance for a borderline OT subject that's beginning to drift
completely OT ;^0  I think I now understand. The bottom line is that pole
pigs still rock as power supplies for large, archaic "dinosaur" SG driven 
coil systems. I'd like to eventually take the leap into DRSSTC land, but I
consider myself just too electronically challenged as well as financi-
ally challenged to seriously take on a megalythic solid state coil system
at this time. BTW, both my 15 kVA pig that powers my Green Monster
coil system and my spare 25 kVA unit are U.S. made -  Solomon, KS.
and Laurel, MS., respectively :^))

David Rieben

-------------- Original message -------------- 
From: "Tesla list" <tesla@xxxxxxxxxx> 

> ---------- Forwarded message ---------- 
> Date: Fri, 6 Jul 2007 17:44:55 EDT 
> From: FIFTYGUY@xxxxxxx 
> To: tesla@xxxxxxxxxx 
> Subject: Re: Vegas pole pigs can't take the heat (fwd) 
> In a message dated 7/6/07 2:42:26 P.M. Eastern Daylight Time, 
> tesla@xxxxxxxxxx writes: 
> >It sounds to me like the said trans- 
> >formers in Las Vegas may have been a bit underrated to begin with and/ 
> >or they may have been toward the end of, or even past their useful life 
> >cycle and the current heat wave may have been the "straw that broke 
> >the camel's back". Any more qualified comments? 
> I'd say it's the combined effect of several related causes. The 
> electrical infrastructure of the USA is still expanding and changing. 
> Over the past few decades, manufacturing has been declining 
> (precipitously so in the past decade). These jobs have been replaced by service 
> industries. Factories and supportive industrial zones were usually located near 
> shipping routes (highways, rivers, rail lines, ports). But offices and strip 
> malls 
> can go anywhere. 
> People have been buying houses like crazy. Again, a housing development 
> can be built just about anywhere. Those strip malls and offices go 
> hand-in-hand with the new housing. 
> People are also living longer. Perhaps because of better quality 
> healthcare being more widely available (affordable is another issue!). More 
> older 
> people alive means they need more doctors to *stay* alive. So more doctors, 
> more lawyers and other service/support industries (offices and strip malls). 
> And 
> they are staying in their houses longer, so there are less houses available 
> which means more new houses for first-time buyers. 
> So the geographic distribution of electrical power is getting more and 
> more spread out, from heavy consumption in urban/industrial centers, to all 
> over the place - even remote rural areas. So this means *more*, smaller 
> distribution transformers to all these little loads. 
> Las Vegas, for example, is a huge electrical load in the middle of the 
> desert. Even in Arizona, housing developments are taking over desert land 
> (right, D.C. Cox?). The irrigation and service industries in these areas 
> further 
> decentralize the electrical loading in areas further from the electricity 
> production. 
> Existing power generating plants were built near industrial centers. But 
> we aren't willing to tolerate new nuclear plants, nor does the population 
> want to live next to a coal-burning power plant. Again, power plants need to be 
> built near transportation centers to bring in fuel, or at least near a body 
> of water for cooling (nuclear). If the houses, offices, and strip malls are 
> being built away from the power plants, more transmission and distribution 
> equipment is necessary to bring the power to the people. 
> Fine, except the people *using* these loads have nothing to do with 
> producing the distribution equipment! Since factories in the US are closing, 
> the 
> pole pigs and distribution equipment is increasingly being made overseas. I 
> see a lot of ABB brand distribution equipment here in the US, and I would 
> presume the quality is high. I *do* know Europeans tend to design things with 
> the 
> smallest "service factor" possible, with the least amount of copper (don't 
> get me started!). And many "American" brands are having their distribution 
> equipment made in Mexico (don't get me started on *that*!) Either way, the 
> quality and/or robustness of foreign equipment is often not up to the "old 
> stuff" 
> that many utilities could "count on" to take the abuse. 
> There's also the side effect of fewer engineers in the USA (because of 
> less manufacturing and more service jobs), and the shift of engineering duties 
> to unqualified personnel. So we have people making decisions about the 
> distribution network who don't have the experience or credentials necessary. 
> I would *speculate* that many utilities are owned by controlling 
> interests that have no experience or knowledge about the utilities business, 
> and 
> only treat their utilities according to profit margin, not quality of service. 
> The materials cost of distribution equipment is sky-high at the moment, 
> due to the metal commodities used in their manufacture. This puts pressure on 
> both the manufacturer (to reduce safety margins/service factors by using the 
> least amount of material to remain competitive in pricing) and on the 
> engineer to keep project costs down (or the project won't happen, or the job 
> bid 
> won't be awarded). So I would suspect increased use of refurbished old 
> transformers - but will fresh oil cure heat-damaged insulation? Diagnostics to 
> test 
> or identify problems in electrical equipment continues to improve, but it 
> costs money and skilled personnel (more money). The lead time for distribution 
> equipment has drastically increased as well. So there's also the result that 
> more loads are put on existing equipment, instead of properly upgrading it. 
> I speak from experience in my neck of the woods, that getting a utility 
> to increase the size of a service because of an increase in load demand is 
> like pulling teeth. At my last two jobs, we increased the load on old services 
> significantly, with continuous demand (18+ hours a day/six days a week). The 
> utility refused to upgrade, and when they did, they ran service conductors 
> that were half the size they needed to be. It wasn't until we threatened 
> lawsuits over loss of service/factory production that we got to explain to 
> *real* 
> engineers the situations and get them corrected. 
> -Phil LaBudde 

Date: Fri, 06 Jul 2007 19:18:39 -0400
From: BRIAN FOLEY <ka1bbg@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Vegas pole pigs can't take the heat (fwd)

Hi, interesting,  originally they were sized for the estimated demand, i bet
if you measured the wattage they are actually running at peak demand, it
probably is more than twice rated. in this town we have 3 transformers
feeding 3 towns from here. the transformers were rated at 200 kva, those
caught on fire in the winter, were replaced by 450 kva, and this spring one
burned up so that one is now rated a550 kva and seems to working ok.
they take a lot of punishment. cul brian f.

Date: Fri, 6 Jul 2007 15:23:09 -0700 (PDT)
From: G Hunter <dogbrain_39560@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Vegas pole pigs can't take the heat (fwd)

This is a puzzle.  I'm no engineer, but I think pole
transformers are protected from overload by a
"blowout" fuse or a mechanical recloser.  If too many
customers switch on the AC, why don't these protect
the transformer from excessive current?

I lived on an Air Force base in the deep south for
many years.  Every year on the first really hot day of
summer, a large polemount (supported on a trestle
between two poles) transformer would fail at the
hottest part of the afternoon.  Even though this pole
unit was 2 or 3 blocks away, I could hear it fail just
before my base housing unit lost power.  I recall the
distinctive growling sound of power arcing so loud it
echoed around the base.  Once or twice I actually saw
the flicker of blue-white light playing off nearby
trees and structures, even in the brassy summer
sunshine.  Once it actually burst into a smokey,
spectacular fire, flaming oil dripping to the ground. 
Fortunately, the errant unit was in an open area away
from houses and streets.

This was between 1984-95, and I've forgotten exactly
how many times it failed, but it happened often enough
that I came to expect it every year--sort of like the
4th of July.  After one such summer failure, I noticed
the replacement unit was much bigger than before.  The
transformer never failed again.  I guess somebody
finally got a clue.

If the smaller, failure-prone unit was overloaded by
peak summer demand, why didn't the protective devices
kick in?