Most walwarts do have protection in them - usually a one-time fusible link, so if you overload it you end up with no output and a small paperweight.
I have some 12V 3amp power supplies I got on eBay for about $10 each. That's enough for over 100 Tortoises. I think they were meant for some small LCD monitor.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinker But you do indeed not want to run right at the max. 75-80% max is usually best. Similar to house wiring - 15amps on a 20 amp circuit, 12 amps on a 15 amp branch.
Randy,
That's something to consider. My experience is that I run as many Tortoises as they will support by moving them effectively, then moving one to start the next circuit as I described earlier.
A quick check shows them to be very modestly warm. But some have been in place 20 years and I don't recall one ever failing. I suspect the design provides a built-in safety factor. The more recent ones are, IIRC, required to meet more stringent standards, but can't really speak to the details of all that. YMMV
Mike Lehman
Urbana, IL
Check flea markets and second hand street markets. A few years ago I purchased a box of wall worts, AC and DC, various voltages, for $5. I've used about half of them. Also, watch when someone in the house or friends are tossing old electronics and save the wall worts from those, too.
D
Thanks everyone for the replies. Now that's very kind to offer the Wall Wart. Private message sent.
I see that Amazon has cell phone and laptop converters, but correct that isn't what I want?
You aren;t even close if you allow 60ma for a Tortoise. You're using less than 50% of your wall wart capacity, more liek 20-25% - a Tortise draws less than 20ma stalled, typically 15-18ma. A series LED does not add any additional current draw - which is why you can use series LEDs with no resistors. 18ma in the Tortoise means 18ma in the series LED. Not even a guess, it's the Law.
But you do indeed not want to run right at the max. 75-80% max is usually best. Similar to house wiring - 15amps on a 20 amp circuit, 12 amps on a 15 amp branch.
I use a factor of 60ma for each tortoise and bi-colored LED. I also leave a 10% safety factor for the wallwort. Only using 90% of the available amperage.
I picked up a 12 volt 3 amp power supply part# PS-1260 from allelectronics.com for $14 a while back to run my Tortoise machines and signal controls. An old computor power supply would also work, but the voltage may be too high. They also have a dual voltage 12 volt-5 volt - 2amp power supply for PS-0512 $6.
Initially, I used new RS ones, too, but the pricing got somewhat ridiculous. Like Carl, I keep a box that I throw wallwarts from old, out of service devices into. 9 to 12 volts work well.
Also consider the amperage. If just a few Tortoises, virtually any will work, but once you have a couple of dozen, consider what your surplus wallwart box offers and the locations where they'll be plugged in in terms of dividing things up between them.
Here's a tip. You don't really need to keep exact track of how many you add to a wallwart. The Tortoises work well with them, until you add one too many. Then when you throw the switch controlling it, it will either move reluctantly or not at all -- you've reached capacity and need to add a new wallwart circuit then. That's also a good reason to add each new machine and test operation of it before moving to the next one, so you'll know when you've reached the limit.
I've been saving the wall warts from all the crap I've thrown out over the years. I have a free lifetime supply.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
Nine to twelve volts DC will be fine. The Tortoise draws about 20 ma.
Some like 9 volts DC as the point movement is slower. Cheap wall warts are everywhere.
An unloaded wall wart will show a higher voltage with a meter. Regulated wall warts will show a constant voltage.
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.
Lee,
If you have an MRC power pack laying around you could use that to power your switch machines. If you don't, a MRC Railpower 1370 can be had on eBay for around $20.
Tom
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
Do I need Wall Warts or something similar to operate a series of tortoise switch machines in DC? If wall warts, what type to purchase and from where? Radio Shack has them for nearly $30 which is too high.
I welcome easy to wire alternatives to wall warts also.
Thanks,
Lee