Power Supplies

Model Railroader Layouts and layout building
1

On my layout in progress,i plan on using 12 tortoise machines,about 30 12VDC accessory lights and 6 Logic Rail signal detector circuits. What amp power supply would you recommend. I know i won’t get an exact answer because my info is vague, but a ball park figure would be greatly appreciated.Thank you.

2

Do you require a good answer, or will the LION’S answer do?

12 Tortoises draw almost nothing, the lamps are a different matter. If they are LEDs they too will draw almost nothing. 3 amps should be more than enough for most applications, that is why the LION went with 10 amps for his auxiliary circuits. I have never put an ammeter on those circuits to see what they are doing. Perhaps I should. I have 23 train platforms with upwards of 25 LEDs on each platform, There are hundreds of signals, about 60 relays and bunches of resistors.

POWER SUPPLY OF LION:

Of course that covers about 7 buildings, with two more to be attached to this once we pull down the last of the 4000 Volt overhead wires. The breakers for those buildings are already in that switch panel on the back wall. The big panels in front are the transfer switches in case the city looses power we can run on our own generators. Typically we draw about 20-30 KW with about 45 KW on Sundays. Our generator is rated at 100 KW, so we are good to go.

ROAR

3

Thank you Lion…your answer will do.

4

Here are some 'ball park numbers:

  • Tortoise - Draws about 17-18 ma ‘stalled’ - about 220 ma for all 12 of them.
  • 12 volt lamps - varies, but typical 12-14v lamps can draw 30-80 ma each! Figure about 50 ma for each one - That is 1.5 amps at 12 volts(1500 ma)
  • Logic Rail Detectors - The photocell version draws about 30 ma each, the IR version draws about 100 ma each. 180 ma - 600 ma…

All of the above can be powered by a 12 volt DC power supply. I really would suggest that you just buy ‘wall wart’ power supplies, and buy a separate one for each application.

You can buy ‘wall warts’ quite cheap via eBay - $6-10 is typical for a 1-2 amp 12 volt output unit. Look for the ‘regulated’ voltage ones.

Jim