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Common power bus for switch motors and LEDs or separate?

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  • Member since
    May 2024
  • 2 posts
Common power bus for switch motors and LEDs or separate?
Posted by pintoks on Thursday, May 23, 2024 12:33 PM

Hello: I am wiring a small (~2' x 13') HO switching layout and currently have a separate power bus, using a 9v 300mA "wall wart", to power 10 Tortoise switch machines. I will next be adding LED lighting to the scenery and was curious if the group would recommend running a power bus for the LEDs that is separate from the bus used for the switch motors, or if it would be ok to use the same bus.

I anticipate having around 150 small LEDs ("grain of sand" type bulbs or slightly larger). If a separate bus would be preferred, would another 9v 300mA bus do the trick?

Thanks in advance for your comments,

Brent

  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Friday, May 24, 2024 7:45 AM

Tortoise switch machines require ~10 ma.   Modern LEDs may require < 5ma.

While a 300 ma wall wart would not be sufficient for 150 LEDs, there's no reason you can have multiple wall warts, each proving power to some section of the layout.   Each should be the same voltage. 

while you could have separate supplied for the LEDs and switch machines, there's really no need to have a single bus around the entire layout for just the switch machines.

greg - Philadelphia & Reading / Reading

  • Member since
    September 2002
  • From: Maricopa, AZ
  • 269 posts
Posted by DanRaitz on Friday, May 24, 2024 9:23 AM

As a rule, I would use separate power supplies for each.

On my modules I'm using a 12VDC .5 Amp wall wart for the tortoise switch motors and a 6VDC 300mA wall wart for accessory lighting.

 

Dan

If women don't find you handsome, they should at least find you handy .... Red Green
  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,484 posts
Posted by MisterBeasley on Friday, May 24, 2024 1:08 PM

I too prefer separate bus lines for separate purposes.  I use 12 VDC lines because I like the warm look of incandescent bulbs.  For a few LEDs I put in resistors.  I also use this bus for my Miller Engineering advertising signs, again lowering the voltage with resistors.  I also installed separate bus lines for streetlamps so I can turn those off separately. 

I run power from a small separate supply directly to the control panel, and then power the Tortoise machines individually from there.  I power twin-coil machines first through a Capacitive Discharge circuit  and then the control panel.  Each turnout gets its own cable.  I use 4-conductor phone wire for that.yes, ther are extra wire, but having them neatly bundled in a cable is cheap.

It takes an iron man to play with a toy iron horse. 

  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Friday, May 24, 2024 3:55 PM

DanRaitz
a 6VDC 300mA wall wart for accessory lighting.

it makes sense to use a lower voltages supply for just LEDs considering that few LEDs require more than 4V

greg - Philadelphia & Reading / Reading

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,484 posts
Posted by MisterBeasley on Saturday, May 25, 2024 10:35 AM

gregc

it makes sense to use a lower voltages supply for just LEDs considering that few LEDs require more than 4V

I use a 12 volt supply for my 16 volt incandescent bulbs.  That gives a softer, warmer glow and the bulbs basically never burn out.

It takes an iron man to play with a toy iron horse. 

  • Member since
    May 2024
  • 2 posts
Posted by pintoks on Monday, May 27, 2024 3:52 PM

Many thanks for the comments. Very helpful and much appreciated.

Brent

  • Member since
    February 2020
  • 31 posts
Posted by know2go on Monday, July 1, 2024 3:47 PM

Hi,

I am a electronics professional of simple solutions. Simple solutions provide for simpler, cheaper and faster troubleshooting and repairs.

On my layouts I ALWAYS use just one common power source. There's no reason or Use Case that cannot be resolved by using a single power source. In either DC or DCC mode.

All the best!

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