Jump to content

A single Power Supply - power rating?

Recommended Posts

Rather than have several wall mounted plugs for my NCE starter control, 12V DC AUX layout power supply and overhead LED layout lighting, I was thinking of using a single power supply.


A 25W Single Output Switching Power Supply from RS Online - RS-25-15 provides 15V and 25W and should suffice for NCE (13.8V, 24W) and DC 12V (with a suitable resistor). My layout is small (1 loco running at a time) and without much lighting on the layout,


BUT with a strip of LED lighting 3m is 25W sufficient?


Any advice most welcome.

25W Single Output Switching Power Supply.pdf

Link to post
Share on other sites

I agree with Iain, the power supply that you are looking at is barely sufficient to meet the needs of your NCE system.  It is not suitable if you have any other power needs.


At 15 Volts the current range is 0 - 1.7 Amps.


If the NCE Command station consumes 24 Watts at 13.8 Volts, then this means it can draw up to 1.74 Amps (24 Watts / 13.8 Volts).

Link to post
Share on other sites
On 21/02/2020 at 20:31, Crosland said:

Don't use a resistor to try and drop the 15V to 12V. Just use the correct power supplies. They are so cheap these days it's foolish to do anything else.



Or LM2596 voltage regulators.


I actually went the other way to the OP as it gives me some redundancy and keeps everything below 2a so isn't a problem for the multicore cable used. Plus the uncoupler uses a solenoid and would cause other accessories to dim if on the same supply.


Powercab- 13.8vDC, ~1.7a,

Tortoise/uncoupler- 14vAC, 2a transformer,

Overhead lighting- 12vDC, ~0.7a draw,

Layout lights/accessories, 12vDC, ~1.3a draw, this then splits to 10v for LEDs, 7v for filament bulb street lights, and 4.5v for electroluminescent controllers and anything that nominally runs on 5v.



Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.