what power supplies do you use for lights ,moving scene displays ect!!

[gandy dancer#1]

Greetings: I have severaldifferent items  for my trains, such as rotating light up airport beacon, then have a rotating radar ower, and want to add lights, street lights and several other scene scape items. Some are 6-12 volt dc max. But some are 6-8 volt <AC> max. So what do yoiu guys use power supply wise for all your extra's?? Need al help i can get starting major project soon.

[Jim Banner]

I have used just about anything that gave the right voltage, the right current (ac or dc) and could handle the load.  But my favourites are computer power supplies.  They typically give +3.3 volts, +5 volts and +12 volts, all dc, and can handle reasonably large loads.  They are invariably labelled to show how much current can be safely drawn from each of these outputs.  And if you have a portable layout, these supplies are a small fraction of the weight of a transformer type supply.  However, you will probably need help from  someone experienced in electronics to set one up for model railroad use.

Many of these supplies use a low voltage circuit to remotely turn them on and off.  Neither the method nor the colour coding seem to be standardized, which often makes it difficult to figure out how to turn them on and off.  And many of them require a minimum load to operate stably or at all.  The later is rarely specified on even mentioned by the manufacturer.  These supplies can normally put out hundreds of watts of power, enough to overload model railroad wiring and possibly start a fire.  The solution here is to use multiple outputs for each voltage, and to fuse each output at no more than 5 amps.

Once your electronics guy has overcome the above difficulties, the outputs can be used this way:

3.3 volts is perfect for lighting the bulbs from rope lights, or at least the rope lights I buy.  They contain three strings, each of 33 bulbs across 115 volts which is 3.5 volts per bulb.  At 3.3 volts, the bulbs last, on average, over 10,000 hours which for all intents and purposes is forever on home layouts.  The 3.5 volt bulbs are the same physical size as grain-of-wheat bulbs costing about $1.50 each at the hobby shop but a string of one hundred 3.5 volt bulbs costs only $16 or 16¢ per bulb.  Not an earth shattering difference until you start putting together lighting over a '50 used car lot and need 100 or so bulbs.

5 volts is just right for running 6 volt lighting such as I have been buying for Hong Kong.  Sure, they ship each unit with a dropping resistor to allow operation on 12 volts, but that just means I am wasting as much power as I am using.  By running 6 volt lighting on 5 volts, I save that power and extend the life of the bulbs by about 30 times.  So if they are 100 hour bulbs, I can expect a 3000 hour life and if they are 1000 hour bulbs, I can expect a whopping 30,000 hour life.

12 volts is a good voltage for running switch machines, 12 volt lighting and 12-16 volt dc animation.  An advantage of these heavy duty supplies wired for multiple outputs is that the 12 volts measured at the supply itself changes very little if at all with changes in load and wiring losses in one output do not affect the other outputs.  So throwing a switch machine wired to one 12 volt output does not dim the lights on another 12 output.

-5 and -12 volt outputs may have some use if you are using certain electronic circuits on your layout but generally are not used.

The only down side of using computer power supplies is the lack of ac outputs.  Thinking back on the last five major layouts I have wired, this has been a problem only once.  On my own layout I have a "nodding donkey" oil well pump that came with an ac motor.  Not a big deal though - a 15 volt ac wall wart supply takes care of that.  Otherwise, properly modified computer supplies have been a joy to use.

Jim

     

[NarrowMinded]

I use everything Jim mentioned as well, one tip I will strongly suggest is to pick different color wire pairs for different voltages for instants I use red and black for 12v DC for 5v (old cell phone chargers) I wire everything with purple and Yellow, Etc.  when I buy something new I don't change the wires I simply dip the ends in the paint color (colour <-for Jim  ) I have chosen for the that voltage.

NM-Jeff

[gandy dancer#1]

Hi Guys: You got me to thinking on my own ,thanks for that !! I was reading and ran across doorbell transformers at home depot, fairly in exspensive 15> 30.00 many with multiple ac outputs 6 volt to as high as 30 volt ac all from 110 volt input!! Seeing as how many of my accessorries are varied, this might be ideal. i have several lionel toys that range from 6 volt ac to 12 voltac!! someare dc, but that not a problem wih a miniature dc power supply, it was the ac worrying me.!! BUt think got handleonit now thanks to replies, new would find answers here!!

[NarrowMinded]

Make sure you use appropriate fuse between power and you accessories as well.


NM-Jeff