If you wish to use isolated outside rails for anti-derailing, you will need a CD unit per switch. Using just one resistor and capacitor per switch (the diode is shared over all the CD-units) saves a lot of money.
Daniel Lang
I use 4700 microfarads and 100 ohms with O27 switches. They recover to 95 percent of full charge in only 1.5 seconds, which is fast enough for me.
If you have more than a few of these things, you don't even need a DC supply to recharge them, just a diode off an AC accessory voltage. This substantially slows the recharge if there are only one or two circuits. But when there are many, they recharge each other virtually as fast as they would from a DC supply.
Bob Nelson
A Day Without Trains is a Day Wasted
The capacitor circuit that Fred advises has two other advantages:
It allows you to use control rails for an anti-derailing feature without worrying about damaging the coils.
Its use of DC to operate the coils makes it possible to use diode logic between the controllers and the turnouts. For example, in a yard throat, you can have a single pushbutton for each track that throws all the turnouts out to the yard lead instead having to throw each one individually.
An interesting substitute for controllers is a pair of studs (screw heads perhaps) on a layout map panel and a grounded probe for touching them to throw the turnouts.
phillyreading wrote: Just thought of something else with the H.O. switch controls and that is they have five wire hookups verses three wires for most O Gauge switch controls. Two wires in, both hot & nuetral, three wires out. Lee F.
Just thought of something else with the H.O. switch controls and that is they have five wire hookups verses three wires for most O Gauge switch controls. Two wires in, both hot & nuetral, three wires out.
Lee F.
That's because the power is routed separately to O gauge switches.
The typical HO or N install is one power lead to the center terminal of each toggle switch, then the other 2 toggle switch terminals go to the 2 leads for the switch machine coils. The other power lead goes directly from the power supply to the center terminal (common) on the switch machine.
In O, the power lead goes directly to the switch machine, and the ground (common) power side is tied to track ground. The three wires coming out to the controller are directly tied to the 2 coils and the third ties to the power lead coming into the switch machine.
Works the same in either case. The O systems allows a 3 wire supplied lead to the controller with no wires from the controller directly to the power supply. This allows locating the controller without regard to location of transformer with fixed (always too short!) provided cable.
hope this makes sense.
Fred W
Atlas switch controllers are designed to work with Atlas switch machines of all scales. So unless the Realtrax has an unusually high current draw, it should work.
That said, the Atlas switch controllers are notorious among HO and N scale guys for the button sticking in the "on" or "down" position, and thereby frying the switch machines. Twin coil switch machines are designed for a very brief shot of high current, and have very low resistance. If the controlling switch sticks "on" and there is enough current available the factory-installed majic smoke inside the switch machine will be released, and the switch machine will work no more.
A good way to prevent switch machine smoke releases, as well as getting snappier performance, is to install a capacitive discharge circuit in the power feed. To use a CD system, the switch machine must be set to use constant voltage, or non-track power. CD circuits are an easy 1st time electronics project that cost about $10 in components. Or they can be purchased commercially for about $30. The CD system will limit current once the initial jolt has been sent. The drawback is that the current limiting precludes the use of switch indicator lights powered by the same source.
Friends don't let friends use Atlas switch controllers unless they have CD systems. Nice alternatives for controlling switches are SPDT momentary toggle switches or a pair of SPST normally off push buttons. I recommend control switches be rated at 3 amps or higher for long life. You can use either AC or DC to power your switch machines, with or without a CD system.
Hope this helps
Don't know if it is possible to use Atlas H.O. switch controls on O gauge even if Atlas O switches. The H.O. switch controls work with A.C. voltage so it may be possible to wire them some how, not sure about the amp rating on those H.O. switch controls.
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