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Tramcar Trev
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I have learned quite a bit today.
1) Variable focus glasses are a waste of time when doing fine work; yes it’s taken me till now to work that out! From here on I’ll take the magnifying lamp out with me…
2) Plastic overhead fittings do not make the grade, my nifty little plastic Section Isolator, herein after referred to its common name of a “Cut Off’ broke the instant I tried to put some tension on it..

So lessons learned I made a new cut off and used some stainless steel that I scrounged from the stuff that stiffens windscreen wiper blades; I just knew I would have a use for it. It’s still a “copy’ of the really old type that was made from porcelain way back when trams were just hitting the period of electrification. I had some nice pictures in an old catalogue (which of course I cant find now) basically a U shaped length of porcelain upside down so the trolley wheel ran inside it, the trolley wire went up through a hole and was terminated so that the 2 sections of wire were insulated by the porcelain. They were not particularly successful; the porcelain proved too fragile and had poor tensile strength. There is only one of these in the LVET to separate the eastern and western sections and I’ve substituted the porcelain with a plastic channel. I’m not actually sure what is going to happen when in use, as the Pulse Width Modulated controllers seem to modulate the negative supply so as the trams have at least 4 wheels the 2 sections will be “joined” while the car passes over the joint, marked by a marble strip between the rails. This as we have discussed before is a hang over from the days of cable trams where marble strips gave the Gripman a visual clue when to drop the cable. They eventually were all replaced with signs suspended from the overhead. Sydney Light Rail has the word “Coast” on signs where they don’t want current drawn….

Anyway it’s another major milestone getting the overhead work started on the Eastern Section. Enough ears (made in WA while I was touring) are in position to support the wire; more will have to be placed to hold the trolley wire central over the bends. Some of the span wires may appear slack too, simply because there is no trolley wire there to provide some tension….
I decided after much agonizing that I would not solder any of the support wires as it would make repairs difficult, and I’m sure repairs and adjustments will be essential.

Pictures are on my blog as well as the sordid detail as to how I made my ears and other fittings....

http://trevs-tramway.blogspot.com.au/

http://trevs-tramway.blogspot.com.au/2012/05/trolley-ears.html

Tramcar Trev
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Ok advice from those more experienced please. I was going to use brass wire for the trolley wire. It is the multi strand stuff used to hang pictures.... Ok so I have about 100metres of it around 20ga but it is springy and would have to be annealed then it's going to tarnish pretty quick, almost as fast as I can string it....

So I now think I should use either tinned coper or Nickel silver wire. The solid nickel silver would be superior as the plating wont wear off and it's fairly tarnish resistant.
I'll have to check the rersistance I guess whuich may put the tin plated coper ahead....
Thoughts?

Herb Kephart
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Trev-

I have been told by numerous "experts" that copper wire for overhead won't work "too soft" will "stretch all out of shape".  One fellow--who's opinion I respected highly-- looked at the wire on the layout that I had back then, and recognized that the running wire was copper--and told me that I had better replace it, for the above reasons. The subject changed quickly when I told him that that particular section had been in use for something like ten years. This was in a loft above my shop, where the temperature sometimes ranged from below freezing, to over 100*F--that's why that layout no longer exists. It was the temperature effect on ME, not the wire that was the ultimate reason for "abandonment".

The secret is to stretch the wire before hanging it. Put it under tension COLD--not electrically heated as I advised in my bit about overhead elsewhere on FreeRails. That advice is for phosphor bronze wire. As you pull on the copper, you will feel the resistance to the pull increase slightly--this is the material work hardening, --quit then and you will have nice straight wire that won't be likely to stretch more.

One of the beauties of large scale is the amount of detail that you can incorporate.

One of the downsides is the amount of detail the you HAVE to incorporate.

Herb

Tramcar Trev
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Herb Kephart wrote:
Trev-

One of the beauties of large scale is the amount of detail that you can incorporate.

One of the downsides is the amount of detail the you HAVE to incorporate.

Herb

Don't I know it....

I bought some of the nickel silver wire from the local beading shop (they supplied all the porcelain insulators) today.
They say its tarnish free and contains no silver. So that may be killing 2 budgies with 1 stone as I wont have to clean it as frequently. Conductivity seems to be comparible with copper but no where near as soft but unrolls very neatly without kinking. The supreme beader was amused when I produced a meter to measure the resistance.....
Should do the job but unlike the brass multi strand it won't hang in a 'catenary" manner "One of the downsides is the amount of detail the you HAVE to incorporate." which would have looked nice......

GUTMACH
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:doh: After reading the above, I much rather go third rail and not string overhead in order to avoid going :Crazy:

BUT, one of my favorite part of watching videos on YouTube is the raised pans.

-Wayde

Tramcar Trev
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Sorry, you will have to put up with trolley poles writhing sensually as the cars perambulate along the line....:glad:

Across the Bridge
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Tramcar Trev wrote:

"I bought some of the nickel silver wire from the local beading shop (they supplied all the porcelain insulators) today......."



What gauge N-S wire are you using?

Will

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It's .712mm dia.... soft... But I will run out the entire length of it and will straighten it by clamping one end, run the other end through a sheave and tie a brick to it for a day or so.....

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OK, so about AWG 21 gauge - Thanks Trev! :2t:

Will

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On the packet it says .075mm 22awg. Confused. So am I.....

Herb Kephart
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Trev--

.075mm equates to .0029".

Nickle silver wire has a relatively high electrical resistance VS copper or phosphor bronze. You are going to have to put feeder wires every couple feet to keep the voltage drop from becoming a problem.

Overhead wire is something that does not scale down successfully. I have never heard of someone using wire that small, even with an indoor layout with more moderate temperature changes. If you are insistent on scale size wire, I would think that stainless steel would be better--lower coefficient of expansion, and a lot stronger. Still would need an inordinate number of feeders, and solder joints will be a weak point mechanically with any wire that small.

Interesting experiment. I shall be watching--

Herb

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Herb Kephart wrote:
.075mm
We are talking about ~0.7mm diameter wire here Herb, not ~0.07mm diameter!

Will

Herb Kephart
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Gollywillikers-

I thought that I read-

"On the packet it says .075mm 22awg. Confused. So am I....."

Now I understand--you wrote that just to confuse me--

OR-----??    That is maybe-------     But if-------

Oh heck! Wake me up when it's all over.

Herb (I think)


Tramcar Trev
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SZTREWTH ( thats Czek for Strewth) now I'm really confused.... the wire actually measures .715 mm using my digital verynears.... I can feed the trolley wire @ every pole if need be by running a bus underneath and soldering to the base of the brass poles.... Excepting the aluminium poles which I could solder too but I'll "do" a mechanical joint there if necessary. If that dosen't work I'll go back to the multi strand brass.... Maybe I could tin plate it? I used to tin plate PCB's in a hot bath of something.... Electroless tin plate....

Across the Bridge
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Trev, I don't think you'll have much of a problem with wire resistance if you put a feed in every few metres or so. You shouldn't need a feeder on every line pole.

Will

Herb Kephart
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Agreed.

Herb

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Well, yesterday was a historic moment; Car No1 ran about 2 metres under the overhead with complete success several times hey even backpoling without dewiring. I still have a long way to go but I have made afew major advancements to my soldering technique and now use a modified pair of artery forceps to hold the ear to the wire while it is soldered....
Avery brief clip on utoob;
http://www.youtube.com/watch?v=C5Veb6iIcwA&feature=youtu.be

Dan D Sparks
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Wow! We are in sync! I also have started stringing overhead on my HO layout. How exciting is it to see those trolleys take their first steps! Man- exciting stuff!




A forest of poles ready for overhead wire.

Dandy

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I have removed all my overhead, viz: http://trevs-tramway.blogspot.com.au/?zx=1aa433e65a193286

Why don't I listen, I knew that the tinned copper was gunna stretch....

I'm also making an improved trolley wire holder upper....


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