I have six Atlas remote turnouts on my layout and I am thinking of junking the Atlas switch boxes in favor of a series of SPDT momentary contact switches. Anyone have any experience/suggestions as to a part # (Radio Shack preferred) and how to wire them up in series the way the Atlas boxes allow. Undertable machines of any kind are not in the equation. I plan to wire the turnouts to the AC terminals of a DC power pack. Trains will run on DCC.
Thanks for any help.
I can’t be much help on the part number, but the wiring is relatively simple. One side of your power supply goes directly to the switch machine’s center terminal. You can simply jumper them, one to another, for multiple machines. The other side of your power supply connects to the center terminal of the SPDT switch and again can be jumpered, one to another, for multiple machines. The other two terminals of the SPDT switch simply connect to the other two terminals of the switch machine.
PS: You can use either an AC or DC power supply for Atlas type switch machines. They’re simply a pair of electromagnets.
Unless you have a large Radio $hack store in your area, they’re not going to have the type of toggle switch you’re looking for. I purchased mine from Mouser Electronics at http://www.mouser.com
You can also get the SPDT center-off, momentary toggle switches from Jameco Electronics at http://www.jameco.com
Jameco’s catalog numbers are 75889, priced at $1.99 each or 75951, priced at $1.49 each. The 75951 is a DPDT, but the function is exactly the same.
Whatever source you get them from, be sure the package or catalog listing says they are momentary in both directions. This is designated by the use of parenthesis, thus: (ON)-OFF-(ON).
And don’t depend on a Radio Shack employee to select the switches for you.
Try Radio Shack part # 275-1547. That should be a SPST Momentary Normally Off.
Thanks for the help. I just ordered from Jameco.
TomDiehl,
I can hardly wait to solder all those jumpers.
No, he really needs a SPDT (Single-Pole, Double-Throw) Momentary.
Incidentally, getting rid of those Atlas sliders is a good move. They have a nasty habit of breaking with the contacts closed. The first time this happens, you’ll say, “What’s that smell?” as your switch machine melts down. The second time, hopefully you’ll remember the smell soon enough to pull the plug and save the machine.
It depends on how/what way you wire the Atlas Switch Machine.
In the 1990 book, “Your Guide to Easy Model Railroad Wiring” by Andy Sperandeo, on page 73, Fig. 9-3 shows both the use of Two SPST momentary push buttons or one SPDT momentary toggle.
Prior to conversion of use of Tortoise Slow Motion Switch Machines, I used the Atlas switch machines and two SPST momentary push buttons as suggested by Andy’s diagram and they worked just fine!
Yes, you can use a pair of SPST’s instead of a single SPDT. The OP specifically said SPDT, though. Generally, 1 SPDT will cost less than 2 SPST’s, and it will take up less real estate on your control panel. However, if you like buttons rather than toggles, then the SPST route is the way to go for you.
I have heard the same thing about Atlas switches getting stuck and melting, which is why I want to go the toggle switch route. Control panel area is also a consideration since I admit that I blew it when I planned my layout and didn’t put enough thought into the location and size of the control panel(s)
Take a look at demarelectronics.com I and others in my operating group have purchased hundreds of a variety of toggle switches from them. Great and fast service and very reasonable prices.
For years I used push buttons from Rat-shack (RED&GREEN)They work fine just dont hold them down they will burn up your switch machines!
JIM
Heres some pics from my site… might help:
…and Use the DC terminals, AC won’t (Shouldn’t) work.
AC or DC will work. The only time you have to use DC is with a diode matrix setup. A simple switch activating a twin coil switch machine will operate on either.
The symbol you’re showing for your power supply is actually for a battery/dry cell, which is where you may be getting confused.
…Hrm, maybe I am missing something, but I just dont see how Unidirectional Torque is produced in a coil (with a permeable core) when AC is applied to it… any help?
And no, I used a battery as a symbol on purpose. It signifies a universal 12Vdc power supply. Its easier for beginners to understand.
"Its easier for beginners to understand. "
I wired up one switch with an Atlas connector box just to make sure it worked, used the AC terminals of the power pack and it worked with no problem. As for me being a beginner, how did you know that?
Outstanding! Great to hear.
The Beginner’s comment was in reference to the schematics, which I drew up for a series of Basic Electrical Tutorials. (link in sig) Based on the questions you have asked, I thought the schematics would be of use to you.
On the theoretical side of the house, I am still earnestly curious to have a discussion about how a unidirectional torque is developed in a coil with AC applied… obivously it works, although I have never gotten it to, and have been bitten by the curiousity bug. Any help?
You’re not applying torque to anything in an Atlas switch machine, you’re activating an electromagnetic coil to pull a steel rod one direction or another (depending on which one of the twin coils you activate). Through a simple lever assembly, this pulls the throwbar to one side or the other.
My point about the battery schematic symbol is that DC isn’t necessary for the Atlas switch machines, in fact, the original Atlas instructions for hooking them up shows the supply wires going to the accessory terminals of the power pack, which on most packs is AC.
Hrm, well its my understanding that if you push current through a coil, a magnetic field is created. This magnetic field will act on either another magnetic field or a permeable core (in the case of a solenoid) and thus a torque is created. If the core is allowed to move, this torque is translated into motion. If you apply DC to said solenoid, then you get a stationary (unidirectional) magnetic field, but if you apply AC to it you should get a fluctuating magnetic field whos torque angle changes by 180 degrees 60 (or 50) times a second… hence why I am confused. Putting terminolgy aside, the magnetic fields created from AC & DC power should NOT yeild the same results… so the AC thing has me stumped.
Okay then, good info about the Atlas Switch machine instructions. I am gonna keep all my tutorials DC since there is very little need for AC (or the theory behind it) on a layout. Thanks though!
Edit:
Never mind, i figured it out. There is a winding on the permeable core that allows a voltage to be induced on it, thus causing current flow, thus causing a secondary magnetic field to be created in opposition of the coil, thus attraction. Both fields will reverse with each other on the half cycle. Straight induction motor theory. Didnt know that the core of the switch machines were anything fancier than a metal slug. Whoodathunkit.
Actually, Claymore, I had already checked out your link well before you responded to my question. It’s very nicely done and I have linked to it on my favorites for future reference. As for the discussion between you and TomDiehl, I don’t understand much of it, and don’t intend to try. When it comes to certain issues, I admit that all I want is the recipe without any explanation as to why the recipe produces a cake instead of a cookie, for example. But, the Atlas switch schematic on the packaging does show the turnouts hooked up to the AC terminal of the power pack.