Author Topic: Lighting Question  (Read 2070 times)

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wm3798

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Lighting Question
« on: May 05, 2007, 04:30:30 PM »
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I just picked up some Miniatronics light fixtures, with 1.5v grain of wheat bulbs.
The plan is to add a light to the turn table bridge, and run it off the track power, which is DCC so it's AC at 14v
I know I have to add a resistor, but I'm not sure where or how to add it. 
Here's the situation...
The bridge has an auto reverser built-in, so the +/- polarity changes.
I know that with an LED, you put the resistor on one side.
I'm all thumbs with electronics, and these lamps were relatively expensive, so I don't want to sacrifice any for trial and error experiments.
A quick wiring diagram would be very helpful. 



You can copy this one and edit it, and re-post it in your reply...

Thanks,
Lee
Route of the Alpha Jets

Lee Weldon www.wmrywesternlines.net

Chris333

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Re: Lighting Question
« Reply #1 on: May 05, 2007, 05:20:36 PM »
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Resistors are non-polarized so are those bulbs so it shouldn't matter what side you put it on. Any further I'm of no help.

SquirrelHollow

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Re: Lighting Question
« Reply #2 on: May 05, 2007, 08:07:49 PM »
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With a grain of wheat bulb and AC power, it doesn't matter where you put the resistor.  You'll probably want to use a bigger resistor than the minimum though, so heat doesn't become an issue.  Some of those bulbs heat up pretty fast. 
Resistors also can get hot in some cases (moreso with AC if I recall), so try to locate it in an area where it can dissipate well.
Radio Shack used to sell variety packs of resistors for about $0.75.  You could find the pack with the most resistors close to what you need and experiment for next to no cost.  Now-a-days it would probably be about $2, but well worth it for a test or three.
-Robert

Uintah Railway, Utah Railway.

up1950s

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Re: Lighting Question
« Reply #3 on: May 05, 2007, 08:28:58 PM »
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When I had my HO , I added lights to the turntable . 3 on each side . 1 near each end so the rail alignment was lit and 1 on each side of the arch . All were about handrail height and mounted on a a tube attached to the handrails . Putting 1 under the arch top becomes useless once the loco is in its way , not that that is what you are planning . The whole idea is to see the wheels and track , as well as provide a lit walkway on either side . 

wm3798

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Re: Lighting Question
« Reply #4 on: May 05, 2007, 08:37:51 PM »
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I hadn't thought about putting lights at the end... maybe if I put them in a series (for a total of 4.5v) then step the circuit down with a resistor to about 3.5v, that would give them a longer life, and cut down on the heat...  It would also look cooler with the lights on the ends of the bridge! 8)

I'll be heading up to the laboratory soon...



meanwhile, the fleet grows anxious waiting for the electricians to finish their work!

Lee
Route of the Alpha Jets

Lee Weldon www.wmrywesternlines.net

up1950s

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Re: Lighting Question
« Reply #5 on: May 05, 2007, 08:57:46 PM »
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Here is one with lights on the arch , one facing in an opposite direction of the other , but offset to the side so the loco doesn't block the illumination . With the Walthers arch this would need a bracket  or 2 . Some have them on a candy cane lamp post with a conical shade so the are above a humans head .

 http://pc.smellycat.com/pics/equip/pc4800.jpg

bsoplinger

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Re: Lighting Question
« Reply #6 on: May 05, 2007, 09:24:32 PM »
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If you end up wanting to go with LEDs, I'd suggest a few goodies from Ngineering: http://www.ngineering.com/accessories.htm

Walthers #'s for these items:
514-N301S2     1/2 Amp Bridge Rectifier -- 2-Pack - Less Than 1/4" Square    1.85
514-N302S2    140ma Micro Bridge Rectifier -- 2-Pack    3.95
514-N31006     100uf Tantalum Capacitor -- 6-Pack    4.95

It is very easy to wire the bridge rectifier. The 2 inputs go to the track power, the 2 outputs go to the resistor & bulb. If you want to use LEDs, the bridge rectifier is marked + and - so you just wire up to the correct LED leads. Very easy. The cheaper (and larger) bridge rectifiers aren't so small they should be a problem to solder. You can add capacitance (600 to 800 uf) to keep the lights from flickering. The Ngineering page shows pretty clearly how to do it all.

Its just as easy to wire up lighting for passenger cars this way. Flicker free constant lighting for about $5 a car and a few minutes. Add in a buck or so more if you have to buy the LEDs and aren't using existing lighting.

... and if you want to put tiny LEDs directly on the bridge, consider:
514-N10212     Super White LEDs 2 x 3mm -- 2-Pack    7.00
514-N10112    Micro Super-White LEDs 030 x .060" -- 2-Pack    4.95
514-N10312    Nano Super-White LEDs .020 x .040" -- 2-Pack    6.75

and in an orange yellow version:
514-N10222    Super-Incandescent LEDs 2 x 3mm -- 2-Pack    7.00
514-N10152    Micro Super Yellow-White LEDs -- 2-Pack    4.95

Many of the items come in larger packs (10 for the rectifier and LEDs, 24 for the capacitors) at a slightly cheaper per item cost.

up1950s

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Re: Lighting Question
« Reply #7 on: May 05, 2007, 09:56:26 PM »
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At the risk of being drawn and quartered , this shot is from the fine book Union Pacific , Official Color Photography Book 1 by Robert A. LeMassena and Robert J. Yanosey , Morning Sun Books .

This shows the light set up at one end of the turntable , the other end is similar . But this was more of a each turntable had its own setup than a standard .


wm3798

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Re: Lighting Question
« Reply #8 on: May 05, 2007, 11:35:40 PM »
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I'll look more carefully at the information I've compiled about Hagerstown, and I'll report my results whenever I feel like it.  I want to be faithful to my prototype... however, I also need to be able to install the system so it looks right and works... With me, the two goals are often mutually exclusive!

Lee
Route of the Alpha Jets

Lee Weldon www.wmrywesternlines.net

up1950s

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Re: Lighting Question
« Reply #9 on: May 06, 2007, 12:11:23 AM »
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Hagerstown eh ... here are some shots of it with lights .



« Last Edit: May 06, 2007, 12:16:17 AM by up1950s »

Chris333

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Re: Lighting Question
« Reply #10 on: May 06, 2007, 01:56:12 AM »
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Must be so you can line up the tracks at night.

wm3798

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Re: Lighting Question
« Reply #11 on: May 06, 2007, 02:48:07 PM »
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Mmm. Goose Necks.  The MP ones are a tad large for this application... I'll have to see what I can dream up.

Lee
Route of the Alpha Jets

Lee Weldon www.wmrywesternlines.net

sirenwerks

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Re: Lighting Question
« Reply #12 on: May 11, 2007, 11:33:11 AM »
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Lee,

You should definitely consider making those goosenecks using Ngineering's tubing to remain faithful to such a unique lamp construction.
Now seeking Pacific NW N scalers to create a Modutrak-style modular club featuring NP's shared mainline between Seattle and Portland. PM me if interested.