I need a power pack to run accessories only. But I am not sure what size to get
how many Amps or Volts. I want to get one strong enough to expand later.
Well, it would depend on what "accessories" you are planning to use.
I have a lot of structure lighting, which I was running from an ancient (like Truman Era) Lionel transformer. I had maxed it out, and every time I added another bulb everything got just a bit dimmer. So, I went to a local electronics place and picked up a 12 volt DC, 1.5 amp wall wart. This cost all of $20, and my lights are all much brighter now.
While replacing the old transformer, I discovered that I was also powering my Walthers traffic light controller. To my surprise, that thing wants 19 volts! It's an odd voltage indeed, so I've still got Mr. Truman's Lionel running, just for that.
There is really no "standard" voltage for things. I have some Miller Engineering electroluminescent signs, which take 3 or 4.5 volts. I found an old wall wart for that. The Kadee electromagnet uncoupler draws a whole bunch of current, so I dug into that wall wart box to give that its own power supply, too.
If most of your need is for structure lights, I'd go with a 12 volt supply. Remember to look for bulbs in the 12-16 volt range to light your buildings, and you should be fine with an amp or so.
It takes an iron man to play with a toy iron horse.
Mr Beasley,
What is a wall wart? I am being serious. I have a lot of building lights as well.
Not only does the Walther's traffic light module take a lot of volts but it will not run many traffic lights either. Is the limit about 4 to 6?
Chris
A "wall wart" is a wall transformer that plugs into a 110V outlet and "transforms" the current usually from AC to DC and are availalble in a number of different voltages and MA (milliamp) ratings .Anywhere from about 3VDC up to 18VDC and usually up to 1000 ma. I use them a lot to power accessories like street and structure lights - its a fairly low cost efficient way to power these. If you have street lights (I have quite a few model power lamps) that operate on 12V DC and draw 30ma each (like most model power lights) you can run 15 or 16 from one 12VDC 500ma transformer.. The AC or accessory output of most power packs can vary up to about 18 or 20 volts and is unregulated. I use some old DC (I'm into DCC) ones to power my Walthers traffic light controllers (and you're right one controller only does about 4 lamps) and turntable.
What size to get depends on what you will be operating.
Once you decide what you will power with it, you need to add up the current draw that the accessories will demand. Total the wattage required, divide by the volts (probably 12 or 16 volts) to get the amperage. Buy a power source with that much amperage plus a little more.
For example (and I'm just making up figures, so don't use them in your calculations!), if you will be powering 10 turnout motors drawing 5 watts each, using 50 2 watt bulbs for various lighting on the layout and have two accessories that use 20 watts each, your total wattage is 190 watts. Divided by 12 volts gives you almost 16 amps required. I would buy at least an 18 to 20 amp power supply. If using16 volts, you will require 12 amps of power. Buy a 15 amp power supply in that situation.
The formula is: watts/volts=amperage (W/V=A).
Hope this helps.
Darrell, quiet...for now
RDG1519 What is a wall wart? I am being serious. I have a lot of building lights as well.
Right, it's a transformer, and often includes a rectifier (AC->DC) as well. In general, the transformer unit is a lumpy box with the wall plug built right in, so the box goes directly into the wall outlet, and a low-voltage wire runs to the device you want to run. They are commonly used for cell phones, desktop electronic phones and computer accessories. As these things wear out, I save the wall warts to use for things like trains. If you look at them, you'll find the voltage and current ratings stamped on the units, hopefully.
I'm running 6 traffic lights off of my Walthers controller, by the way. I think it's rated for 2 full intersections, which would be 8 lights. Since the lights are LEDs, the current draw should be very small, and you might get away with more lights than it's rated for.
I use DCC, and I use a tiny Bachmann power pack that comes with train sets to power my accessories... Even if I used DC, I wouldn't use my track power pack to run accessories.
My approach, on a large-ish model railroad with a lot of lights, is to power the accessories in a zone from a dedicated power supply. Where the load is just a few signals and building lights I use one of my motley collection of toy train controllers. If the load is too much for those (typically) 0.7 amp units, I go with filament transformers, which can be had fairly inexpensively. I mount mine inside plastic freezer boxes, since there are 120VAC input connections as well as low voltage output connections. The heaviest one presently in service has a maximum output of 3 amps at 12.6VAC. It powers the turnouts for two hidden yards as well as panel indicator lamps and minimal netherworld illumination
A good source of higher voltage, high capacity wall warts are the leftovers from cordless tools and devices that have failed.
My sister used to haunt yard sales, so I ended up with a number of toy transformers and $0.10 wall warts. (I also was gifted with the ruins of the toy sets those transformers were sold with.)
Chuck (Modeling Central Japan in September, 1964 - as cheaply inexpensively as possible)
Here are some links to a wall wart search. There are a lot available. Some are AC, some DC, some regulated. The unregulated ones will measure somewhat above their rating with no load which confuses some people. The voltage will drop down when a load is connected to the wart. A wall wart with 1.5 amp to 2 amp would probably be sufficient for most home layouts. Voltage may be dependent on what your are operating. A club I belong to uses and old mrr power pack for operating slow motion switch machines and lighting, about 12 volts, DC. I connected 5 volt regulators I made to the 12 volt DC buss to control IC logic for signal lighting.
http://www.google.com/search?hl=en&q=wall+wart+transformers&btnG=Search&aq=f&oq=&aqi=
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
I've got a bunch of old Tyco power packs I intend to run accessories with, not to mention several unused wall warts from old tools and guitar stomp boxes.
Flea markets and yard sales are great for picking up all that junk noone else wants and turning it into useful junk under our layouts!
PS: thanks for the formula Darrell, that's going to come in very handy when wiring up all that junk!
dgwinupThe formula is: watts/volts=amperage (W/V=A).
Not too shabby of an explanation!
Do you have any idea how many model railroading electrical handbooks you have to read to see it explained this simply?
Conemaugh Road & Traction circa 1956
I use a 500 Watt computer power supply -- puts out 12 and 5 Volts regulated DC at up to 30 Amps, which is perfect for Tortoise switch motors, signals, crossing gates, sound modules, building lights, etc. -- anything that needs up to 12 Volts. If you have an odd-ball requirement for 16 Volts AC, then any old power pack should suffice.
Most wall warts are limited to only 1 Amp or less and can easily be overloaded and go up in smoke or fail from heat buildup. There's the additional problem of having no way to turn the wall wart off other than unplugging it.
cacoleThere's the additional problem of having no way to turn the wall wart off other than unplugging it.
I use an outlet strip w/on-off switch.
Kenfolk cacoleThere's the additional problem of having no way to turn the wall wart off other than unplugging it. I use an outlet strip w/on-off switch.
Wirh my larger layout (double garage filler) I have a separate 120VAC circuit which powers several of those outlet strips from a single socket through a single master switch that controls power to the rails and all other on-layout circuits. Since it was intended to power the garage door opener that isn't there, it has ample capacity. Since it isn't attached to the structure of the building, the local Codes enforcers consider it to be a (rather complex) extension cord.
Room lighting and machine tool power are on separate circuits
Chuck (Modeling Central Japan in September, 1964)
Hello,
I possibly have the same quandary regarding powering accessories on my layout. I plan on running my trains using a DCC controller, though I've heard that I should definitely not try running accessories from the DCC bus. With that in mind, I've also read that you can use wall warts to cheaply power A/C accessories, though I'm wondering exactly how I'd connect them to accessories such as railroad crossing and traffic signals.
dadret A "wall wart" is a wall transformer that plugs into a 110V outlet and "transforms" the current usually from AC to DC and are availalble in a number of different voltages and MA (milliamp) ratings .Anywhere from about 3VDC up to 18VDC and usually up to 1000 ma. I use them a lot to power accessories like street and structure lights - its a fairly low cost efficient way to power these. If you have street lights (I have quite a few model power lamps) that operate on 12V DC and draw 30ma each (like most model power lights) you can run 15 or 16 from one 12VDC 500ma transformer.. The AC or accessory output of most power packs can vary up to about 18 or 20 volts and is unregulated. I use some old DC (I'm into DCC) ones to power my Walthers traffic light controllers (and you're right one controller only does about 4 lamps) and turntable.
I like to use DC power supplies like this:
DC Supply
They have quick acting overload/short protection and can be adjusted slightly up or down from the 12V. output.
Good Luck, Ed