Lighting My Layout

[jonathan]

Well, here I sit on a Friday night.  The kids are at Nana's, my wife is upstairs playing something called 'bunko' (sp), and what am I doing?  Making trees!  Yes I said I would take a break.... but I'm procrastinating.  The time has come to consider lights and signals for my layout.  The structures are nearly done.  I have 'repaved' the streets and parking lots.  The trains are running fine.  So it's time for lights.  I knew this moment would come.  So.... here are my questions.  I am a little ignorant on electricity.  I have read this forum, Wiring Made Easy, and a host of other on line advice on lights to prepare, but the truth is  I just want to keep it simple.  Here's what I want to do, please show me the error of my ways:

I have four accessory connections (AC) available from four transformers for my DC system.  I want to run lengths of wire under my layout from the AC outputs.  Then, I want to connect any lights I use in 'parallel?' along those lengths of wire.  Is that connecting to a bus?  I wish to continue connecting to the same length of wires until the lights start to dim.  Then I'll use the second accessory output to wire more lights until THEY start to dim, and so on and so on.  My head hurts from trying to figure out voltage, milliamps, resistors and the like.  It seems to me, if my LHS sells a light for my layout, they ought to work without having to worry about blowing up a bulb right away.  Am I naive?  Again, to keep it simple, will that work?  I am planning street lights, as well as interior lights for my buildings, and oh yes, some tower lights for my freight yard.

Also, I want a crossing signal where my road crosses the tracks.  I like the NJ International lighted crossbucks with gate.  I won't even think about operating the gate, but I want to make the signals flash.  Can I hook the flasher unit up to my accessory wires as well?  Do I need a toggle to turn these things off and on?

If I'm on track so far,  The final question is, with four accessory outputs, do I have enough juice to run a few dozen leds or GOWs plus a crossing signal?

Sorry for rambling.  Here's a pic for being so kind as to read this.

Regards,

Jonathan

[buzz]

Hi Jonathan
I have a separate transformer for lights and accessories this way they don't interfere with the trains.
The First light I wire in series then after that they go in parallel this will dim them a bit to start with the lamps last longer and you get a better appearance when they are lit

All the bits for the level crossing can be wired to the accessories transformer but really read an digest the manufactures instructions.
they will probably be electronics and may be voltage type and or polarity sensitive.
All the bits to have the trains turn the crossing on and off are available.
look for a flash light mast with LED's it will look better the same goes for train signals.
From your description you should have plenty of available power.
But afraid your going to have to find the formulas and do the calculations to find what you can run on each transformer
regards John

[Jim Banner]

A photo like that will calm me down and fire me up, both at the same time.

As far as your lighting goes, you are on the right track.  But I would not rely on the lights looking dim as a way to avoid overloading your power pack.  A much better way is to measure how much current your lights are drawing from your power pack.  A digital multimeter is a good, low cost investment.  Some of them will measure ac current, but many will not.  An alternative is to wire a one ohm, five watt resistor in series with the power pack, i.e. between one of the power pack connections and the bus wire that would normally connect to it.  With such a resistor in the circuit, you can measure ac voltage across it and read it as current through it - the number will be the same.  Alternately, run the bulbs off the dc (track) terminals.  Then you can measure the dc current the bulbs are using (all multimeters read dc amps.)  Just remember to keep the speed control turned full up.

Normally, there will be a rating on each power pack.  It may be in volts and amps or it may be in VA (which is volts times amps.)  If the rating is in VA, just divide by 16 - that is how many amps the pack is good for.  Many small power packs are rated at about 16 VA which means they can put out 1 amp.  Some are more, some are less.  Grain of wheat bulbs rated 12 to 16 volts usually draw about .065 amps each but this can vary quite a bit.  (I would not advise you to use 12 volt grain of wheat bulbs - they will burn out too fast with power packs rated at 16 volts.)  So you could expect to run at least 10 and maybe as many as 15 grain of wheat bulbs on a 16 VA power pack, or half that many on an 8 VA pack. 

Once you have calculated how many amps each pack can supply, it would be a very, very good idea to put a fuse rated for that current or less in series with its output.  While power packs are supposed to have self resetting circuit breakers built in, the circuit breakers are not very reliable when it comes to protecting the pack itself.  It will keep you house from burning down, but not your pack from burning up.  A fuse will protect both your house and your power pack.  And if you really don't want to fuss around with meters and amps and volts, it will also tell you when you have added too many bulbs to that bus.

Bottom line, four power packs, four fuses, four buses and, if you want, four toggle switches on your control panel.  The alternative for the toggle switches is to plug everything into one power bar and turn that on and off.  Now go back to your own post, admire that photo for a while, and relax.  Then get to work.   

Jim

p.s. You might want to reserve one of those power packs for operating turnouts (track switches.)  This is a good way to keep the building and signal lights from dimming when you throw a switch.

J

[jonathan]

Great advice!  Thanks Buzz and Jim.  I'll print these and start working on the proper ohms, amps, multimeter, etc.  I hate electrical math, but I knew this day was coming.  Thanks for the tip on the turnout motors, too.  I was going to try to run lights and turnouts thru one pack, but no longer.  I have enough juice to keep them separated.  Thanks again.

Regards,

Jonathan