MisterBeasley Most supplies have an internal one-time fuse that can not be replaced, and when it goes you are left with a fairly ugly paperweight with wires coming off it.
Most supplies have an internal one-time fuse that can not be replaced, and when it goes you are left with a fairly ugly paperweight with wires coming off it.
Not if you cut the wires off once it's kaput.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I have too many power supplies, because I started with re-purposed wall warts and just kept adding more. Phase 1 of my layout is a mess. On Phase 2 I learned my lesson and bought a "real" power supply, 4 amps at 12 volts from an online electronics place. My incandescent structure lights and streetlights are all 16-volt, so running them at only 12 volts gives me a softer, dimmer and "warmer" glow, and prolongs bulb life. While the look of the bulbs is "warmer," the temperature is actually cooler.
My Miller Engineering signs take either 3 or 4.5 volts. I run them off the 12 volt bus, too, by using a resistor.
I've also got a few Kadee electromagnet uncouplers. These are a special case. They take a lot of power, and I found that when I connected them to the same supply as my lighting, the lights dimmed all over town when I wanted to uncouple a car. So, those have their own supplies now.
Another consideration is the physical arrangement of your layout. Mine has now grown from a single "table" to 3 walls. That would be a lot of bus wire between the supply and the lights, so I've broken my lighting into three segments with separate supplies. This also lets me distribute the load so I don't put too much on one supply.
And, speaking of putting on too much load, it's a good idea to add fuses to your lighting bus. Get a fuse rated lower than the supply can handle, to give yourself some margin of safety. Most supplies have an internal one-time fuse that can not be replaced, and when it goes you are left with a fairly ugly paperweight with wires coming off it.
It takes an iron man to play with a toy iron horse.
cedarwoodron With a DCC-wired layout, to provide power for remote switch machines, lighting, etc- how much power (12v, 16v, etc) should an auxilliary DC power supply have, to allow for these various other electrical operations? Cedarwoodron
With a DCC-wired layout, to provide power for remote switch machines, lighting, etc- how much power (12v, 16v, etc) should an auxilliary DC power supply have, to allow for these various other electrical operations?
Cedarwoodron
Rich
Alton Junction
I use a Zephyr for running all trains. I use a 12 volt power transformer from Radio Shack for all switch machines, and an old MRC power pak for lighting and signals.
Another issue is whether you want specific voltage or control of same for different type things. I have a MRC 1300 I just use for testing things (a DC loco, lights, etc). But I wanted the Circuitron DC power supply for my 20-some Tortoises. I think it is a regulated walwort so the Tortoises behave the same (speed of movement) as I added turnouts. I put some turnout indicators (signals) on a separate 12 regulated Miniatronics walwort. And I'm now adding several more for some structure lighting circuits, each with a 1a 12v walwort, adding a 3/4 amp fuse. Each will handle up to scores (75 or so) of 9ma christmas LEDs w/resistor, or about 30 of the 25ma 3-LED/resistor strip lights. I like the idea of having multiple aux setups, so any problem is confined to one area. It costs a bit more (about $20 per setup) than maximizing utilization of MRC type devices. Of course my regulated voltage walworts are not adjustable, other than adjusting the resistors added to the LEDs.
BTW I'm learning that structure lighting can vary lots on how much lighting (and power) is desireable. On my first small industry office I think 2 9ma LEDs (18ma) will do. On a larger "crane & shovel" industry shop, three 3-LED strips (75ma) seems preferable. So it's a learning process. One more reason I like the building block approach, with a number of subsystems.
Paul
Modeling HO with a transition era UP bent
As NeO684 has stated, it depends on the total amperage of all the devices you want to power, and the type of devices you want to use. Tortoise machines use about 15ma (1000ma =1 amp) lights can use up between 30-50ma per bulb. LEDS use considerably less but I have very little knowledge is this area. After adding up everything you want to power add about 20% for a safety factor. It is a good idea to go even bigger to allow for unforeseen additions. This can be done by using one larger power supply or adding smaller ones as you go.
well, the voltage doesn't really matter, in the sense that you can always add a dropping resistor to the mix. The kicker is the amount of amperage that the power supply is capable of supplying.
You can run 100 tortoise machines off one supply, if it has a high enough amp rating (1.75A or higher), but if you have just a tiny 500 mA wall wart, it can only run like 35.
-Dan
Builder of Bowser steam! Railimages Site
Most DC power packs like MRC's can power solenoid switch machines from the Accessory (AC) terminals. Tortious machines can be operated by the same pack if it has a fixed DC supply or by leaving the throttle in the full power position. I would recommend getting a capacitor discharge unit like circuitrons snapper for the solenoid type.