Hi Guys,
I've been "away" for a while and need some help regarding lighting up the buildings on my layout. I have 6 power packs feeding DC power to my Aristo-Craft walk-around throttles (I built my layout 8 years ago before DCC was as popular as today). Now, I want to light up buildings along the layout and wondered if I can just tap into each of the power pack's "accessories AC" output, WITHOUT disturbing the DC voltage each pack supplies to my power blocks. I seem to recall that the "accessories" are a separate function on the power packs and shouldn't effect the DC output, but I want to be sure.
I would guess that each pack can only light up 7-8 buildings (12 volt bulbs) but again, I have 6 power packs, which should accommodate the 50 or so structures I need to light up. I realize that if I wire the lights in parallel, the total brightness of each bulb will be diminished as I add more to the "string". As I recall, parallel wiring means that each light has a wire connected to both the positive and negative coming from the power pack. I don't want to wire them in series because then, I believe, if one light burns out, they all do....correct?
Any help would be appreciated.
Thanks,
Mondo
Your power packs may or may not be able to support eight or so lamps on the accessory output without adversely affecting the DC power available. Each pack should have a rating probably expressed in VA (or Watts) - a Tech II I just checked is rated at 13VA, with 14VDC and 18VAC outputs. Translating, that means that at full throttle, there will be a tad less than one amp available for train propulsion and lighting if there is no load on the accessory output. Any load on the 18VAC terminals reduces the power available to the attached throttle. If your (fill in name of passenger train here) has two powered units and a dozen lighted cars, the example I cited would probably be over-maxed trying to provide track power. (My DMU express only has six cars, but three of them are powered by 1960s-issue open frame motors. It would overload this pack if I ever ran it at full voltage. It would also be WAY over the line's 90kph speed limit!)
A better solution for fixed lighting is to use what I refer to as 'junk' transformers or powerpacks - old wall warts that once powered now-dead devices, toy train transformers acquired at yard sales and the like. Over the years I have gathered about a boxful, and they are being recycled as necessary to power switch machines, panel indicators and (when I get to the point that I have some scenery) street and structure lights. Another possibility is to use a low voltage light transformer - the type meant for low-intensity outdoor lighting - or small filament transformers if you prefer distributed power.
As for running lamps in series, that allows the use of low voltage lamps. Yes, the whole string will go dark if one lamp fails - but finding the failed lamp is as simple as touching the leads of a good bulb in parallel to each one in the string. (I bring all my electricals out to terminal blocks at the layout edge, so I can do my testing right at the fascia. No need to lift a roof unless you're sure which roof covers the dead bulb.)
Just my . Other opinions are sure to differ.
Chuck (Modeling Central Japan in September, 1964)
Chuck,
I see you haven't lost your touch at providing clear, well thought out responses to questions.
Thank you so much,