DC Power Management

The Beautiful Golden CO Model Railroad

12 Volt DC Power Bus Management

The other night I was working on the layout connecting a device to the 12 volt DC power bus I have on my new layout. Soon I smelled something electrical over heating. I immediately shut'er down. I knew where the problem was and was able to fix it easily. Then I began to think that there needs to be a over load/short circuit protector. I have my track power fully protected but not my 12 volt DC Bus. I thought of putting a automobile light in series in the circuit which will "light up" if too much current is being drawn through the circuit. Then I remembered I had a DC Amp meter laying around too. So I designed a 12 Volt DC Power Management panel with a power switch, amp meter, and an current over draw/short circuit light.

The DC Power Manager.

12 VOLT DC SUPPLY

There are a lot of uses for 12 volts on a layout. I do not want to draw the 12 volts from my DCC system so I set up an independent 12 volt power supply. I want a supply that will give me about 8 amps which I hope will be plenty of current to run the devices such as switch machines, building lights, and other 12 volt things I will eventually add to the layout. I have about 11 amps of total available but I will not want to draw more than 8. My amp meter goes up to 10 amps so I should be able to monitor the amperage I use (The switch above the DC Power pael is the Master'; AC Switch).

The Hay Wire.

THE CIRCUIT

I bring the both the positive and negetive 12 volts into the panel. Most of the ciruit is on the positive side. It first goes to a pwer switch. I have a green led on top of that which indicates that I have power. The negative side of the led goes to the negetive terminal. The current then goes to the amp meter and then to a positive "out terminal. I use the "European" style terminals which allows secure bare wire binding. I put a electrolytic 220 mirofarad capacitor across the positive output and the negative to "clean up" the DC voltage from any left over AC sine wave. The capacitor may be a little too large as it adds a "momentum" effect of a few seconds to the shutdown.

PART 2

Devices using the 12 volt Bus.

DC Power Eaters

Here are two devices that draw 12 volts from the bus.

The Power Supplies

The DC Power Supplies

Here is a view of the power supplies. I have an old battery charger along with two 12 volt 3.3 power supplies I got from All Electronics on sale. These are all connected in parallel so that the voltage remainds 12 volts but the amperage is added together.