rrinker 30V is a bit high to power regulators, most of them don't go that high. A few diodes will drop the voltage a bit, 20 of them will get you down to about 16 volts. Seems nuts but a couple dozen diodes with an amp rating high enough to handle the pwoer suppyl will only be a coupel of bucks, cheaper than a different power supply. They also won;t get hot. Once does to a range a voltage regualtor can handle, you can feed it into those and further reduce it to specfic requirements. --Randy
30V is a bit high to power regulators, most of them don't go that high. A few diodes will drop the voltage a bit, 20 of them will get you down to about 16 volts. Seems nuts but a couple dozen diodes with an amp rating high enough to handle the pwoer suppyl will only be a coupel of bucks, cheaper than a different power supply. They also won;t get hot. Once does to a range a voltage regualtor can handle, you can feed it into those and further reduce it to specfic requirements.
--Randy
Depending on what you're driving, those 20 diodes will still generate heat. Alternate is to simply use a power resistor or two and build divider to get the vdc you're after.
rrinker 30V is a bit high to power regulators, most of them don't go that high. A few diodes will drop the voltage a bit, 20 of them will get you down to about 16 volts. As for using it to power a CD switch machine supply, be careful about that. Especially if it is an AC power supply - when rectified and fed into the CD unit, the peak voltage is much higher than 30V. CD supplies meant to be powered with 12V use 25V capacitors for a reason. If you build your own and power it from a 30V power supply, use 50V capacitors or higher, 25V ones and even 35V ones will be overstressed and fail. Spectacularly I would block a higher voltage with a few diodes before feeding say a 16V bus into a regulator set to deliver 1.2 volts though, the excess is all dissipated as heat and reduces the load capacity of the regulator. Ideally you only want a few more volts going in for headroom, not a massive difference between input and output. Feed a 5V regulator from 18V and it will get rather warm even with no load. --Randy
30V is a bit high to power regulators, most of them don't go that high. A few diodes will drop the voltage a bit, 20 of them will get you down to about 16 volts.
As for using it to power a CD switch machine supply, be careful about that. Especially if it is an AC power supply - when rectified and fed into the CD unit, the peak voltage is much higher than 30V. CD supplies meant to be powered with 12V use 25V capacitors for a reason. If you build your own and power it from a 30V power supply, use 50V capacitors or higher, 25V ones and even 35V ones will be overstressed and fail. Spectacularly
I would block a higher voltage with a few diodes before feeding say a 16V bus into a regulator set to deliver 1.2 volts though, the excess is all dissipated as heat and reduces the load capacity of the regulator. Ideally you only want a few more volts going in for headroom, not a massive difference between input and output. Feed a 5V regulator from 18V and it will get rather warm even with no load.
Right you are Randy. I should have been more thorough in my initial response. Luckily we can all count on you to fill in the blanks. Good info as usual!
Expanding on my first post, regualtors are commonly available in 15, 12, 9, 6, and 5 volt versions, plus there are the adjustable type which can deliver a wide range of voltage, determined by the values of resistors used. So you cna get any voltage you like, from your full supply voltage on down to 1.2V. I would block a higher voltage with a few diodes before feeding say a 16V bus into a regulator set to deliver 1.2 volts though, the excess is all dissipated as heat and reduces the load capacity of the regulator. Ideally you only want a few more volts goign in for headroom, not a massive differnece between input and output. Feed a 5V regulator from 18V and it will get rather warm even with no load.
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I use old PC power supplies as well. I have tapped off the 12V and the 5V and run a pair of power busses around the layout. Then when I add a structure it is just a case of connecting to the bus.
Simon Modelling CB&Q and Wabash See my slowly evolving layout on my picturetrail site http://www.picturetrail.com/simontrains and our videos at http://www.youtube.com/user/MrCrispybake?feature=mhum
very good info Guys...
CharlieM90 I use multi-tap (+5vdc, +12vdc, -12vdc) switching power supplies sourced from surplus electronics distributors such as Alltronics. That usually takes care of most things. For the odd stuff such as 9v, 3.3v, 18v, etc. I usually just use an adjustable regulator or (if really off-the-wall) a dc-dc transformer and then regulate. I hate wall-warts. Hate managing them. Hate having to sort out what goes to what. Would rather just build my own supplies and not keep buying multiple outlet strips that quickly get loaded with various sized bricks plugged in.
I use multi-tap (+5vdc, +12vdc, -12vdc) switching power supplies sourced from surplus electronics distributors such as Alltronics.
That usually takes care of most things. For the odd stuff such as 9v, 3.3v, 18v, etc. I usually just use an adjustable regulator or (if really off-the-wall) a dc-dc transformer and then regulate.
I hate wall-warts. Hate managing them. Hate having to sort out what goes to what. Would rather just build my own supplies and not keep buying multiple outlet strips that quickly get loaded with various sized bricks plugged in.
I use old PC power supplies. Some of them require a load to remain on so you have to add a resistor to keep them from shutting down. I get 12V, 5V and even 3.3V out of the ATX supply I am using. Cheap, clean, reliable power.
hobo9941 Question: I have a nice 30 volt power supply from a Lexmark printer I threw out. Any suggestions what it could be used for?
Question: I have a nice 30 volt power supply from a Lexmark printer I threw out. Any suggestions what it could be used for?
It might do for a Capacitor Discharge power supply if you use twin coil switches? Is it 30V AC 0r DC? You could use it as an accessory supply with a regulator circuit to drop it down to what you need. If it's AC and you need DC add a rectifier to the mix, as others have mentioned.
I have a 12 volt power transformer from Radioshack, for powering the turnouts.
I have a 4.5 volt wallwart to power a couple Miller Engineering signs.
I have a Zephyer for train power.
And I have an MRC DC power pack for lights around the layout.
I also have an old Lionel transformer for 18 volts ac for a couple accessories, like Walthers Traffic Signals.
Old transformers and power packs are readily available at train shows, for not much money. Using a voltmeter, you can dial up whatever voltages you need. Running 12 volt lamps at a little less voltage makes them last a lot longer.
My subway station lights are track powered because I always want them on when the track is powered. Everything else, lights, DS-64s, etc., is powered by 14V wall warts, one for each 8 foot section of my layout. My switches, both tortoise and snap, are powered by the DS-64 that controls them.
Dave
Lackawanna Route of the Phoebe Snow
I have standardized on 12 volts for my lighting. That handles all my buildings and streetlights, as well as the interior lighting in the subway stations. I use 16-volt bulbs for all of these. The Walthers Cornerstone streetlights are also 16-volt. By running them at 12 volts, I hope to have them last forever, and they look much better at the lower voltage, anyway.
But, I still have not one but two power strips full of wall-warts. I've got an old powerpack I use for the turntable motor and to power turnouts, through a CD circuit. I need both 3 and 4.5 volts for my Miller Engineering signs, and I run my Tortoises on 9 volts. The Kadee electromagnet uncouplers need a beefy 16 volts at 3 amps, so they've got their own power. And the Walthers traffic light circuit needs the completely bizarre 18 volts, which I pull from an old train transformer.
Standardize what you can, but until the manufacturers stop asking for oddball voltages, there's no choice but to comply.
It takes an iron man to play with a toy iron horse.
Good info/post Randy, multiple power strips with multiple voltage wall warts is what I'd like to stay away from. Just look through the Walthers catalog in the lighting, signs etc sections and your taken aback by all the different voltages. Not only do they have different voltages, but some have there own power sources, some have battery hookups for 9v or other batteries, some run off of track voltage. Some things where designed to run off of the accessory side of a DC power pack, which I believe is usually not more than 14-15v. If your using DCC, you need yet another power source for these items.
With the trend towards LEDs in everything, this isn't nearly the problem it once may have been. I plan on heavily using LEDs for structure lighting - just not the bluish-white ones, they look all wrong except for certain modern situations, and I model the 50's. Back in the day, you tended to use the same voltage bulbs for everything. No need for a plethora of different powr supplies. Now that there are many other electronic/animated thigns besides simply putting lights everywhere, it's a little tougher. The easiest thign to do is standardize on some certain top voltage, say 16V, and never buy anythign needing more than that. For things that need less, you can build small voltage regulators and tap off the 16V bus, regualtors are avaialble in most any of the common voltage requirements, and the circuits are fairly simply. A TO-3 cased one (the black square with 3 legs and usually a metal tab) are good for about an amp with a heat sink, half an amp without, and also automatically shut themselves off if overheated (not really a substitute for a proper fuse or circuit breaker, but an extra level of protection). For ultimate compatibility maybe the bus run would be AC, for each regulator then you'd also need a rectifier bridge and filter capacitor. Still only a coupel of bucks per regulator, and it beats multiple power strips full of varying voltage wall warts plus multiple runs of wire around the layotu to power various things. For a larger layout, you might need multiple main power sources, with each oen feeding a section of the layout, much like a DCC power bus.
Today there are sooo many items such as streetlights, interior lighting for buildings, street signals, special effect lighting, signs,turnout motors, turn table motors, vehicle lighting, signals, sound systems etc,etc, etc, for our layouts that operate on different voltages. So the question is, how do you manage all these different voltages? Do you have a couple of power strips full of wall warts? Do you only buy items of a similar voltage? I would like to hear how you folks manage this. This thought came to me as I was thinking of making my own streetlights and was trying to decide what voltage bulb to order. Opinions please.Pictures would be nice.