switch controls

[Anonymous]

I'm building a new layout and want to use toggle switches to control turnouts. I wired my panel using DPDT-center off-momentary toggles and when the power was turned on-cooked all my turnouts. What did I do wrong and how should they be wired?

[Leon Silverman]

Sounds like you have solenoid-type switch machines, such as Atlas, Peco, or NJ International. These machines snap the points of the turnout from one side to another. These machines are meant to be powered only momentarily and will burn out if the powered is left on for any length of time. You need to utilize a momentary contact type switch (push-button for example) to control the turnouts. Those DPDT toggles would have worked if if they were spring loaded and returned to center position when you released the pressure on them.
Slow motion switch machines, such as Tortoise, are designed to be powered all of the time and will not burn out under these conditions.
If your toggle switches were actually spring loaded so that the power did not stay on, then there was a wiring error. The wire going to the center of the solenoid does not have to routed through a switch. All of the switches can be fed through a single bus wire off you power source. The outer terminals of the switch machines have to go through the momentary contact directional switch.

[NZRMac]

I've just wired my turnouts with twin coil switch machines.
I used pushbuttons from a used electronic washing machine and a capacitor discharge circuit.
If you leave your finger on the button no burnouts because the capacitor sends a quick pulse of current then shuts off till the next charge, after you release the button.

The circuit would work with your dpdt switches ok

I have a simple circuit if you want.

Ken.

[trainmaster66]

I don't know how you are wiring the DPDT switch you mention, which may be the burnout problem. I would use only a miniature SPDT momentary 2 sides switch or you can use a regular size, although more expensive. I find that the miniature one by Miniatutronic Corp., Deer Park, NY 11729, model number 36-220-02 have worked fine on my layout with 54 twin coil machines. I am not nor have ever been a representative of Miniatronic Corp. The center lug would go to one side of a DC or AC terminal of a power supply giving not more than 17 volts. Less down to about 12 will quite often work on a single machine. The center tap of the machine goes to the other terminal of the power supply. Then each side lug goes to the outside lugs of the machine. Each machine should have a very good instruction sheet supplied. If you follow that to the tee, you should be fine. But, when you mention a DPDT switch, you got me confused there.
Jerry

[SpaceMouse]

I'm a total newbee and the most extensive wiring I've ever done is a net work in my business. But does anyone ever use a telephone wiring block to organize their swithes. It seems taylor made for the job and they are cheap (although I guess the tools are a little costly.)

[Anonymous]

If wanting to use toggle switches to operate turnouts, I would use SPDT (single pole, double throw) rather than DPDT to do the job.

But, like the warnings in the other posts, they must direct power to the turnout only momentarily. This can be accomplished with a switch designed to spring back to the center whose positions are "momentary-on, off, momentary-on." Obviously, the turnouts can still be destroyed if the switch is accidentally or intentionally held in either "on" position.

NZRMac's idea seems like a good one.

[nobullchitbids]

Best way to wire solenoid-type switch machines for reliable operation is to use a capacitor-discharge circuit, a diode matrix to route the charge to all the machines relevant to a selected route, and momentary push buttons to put the "jolt" in motion.

What you did was allow current continually to flow through the switch-machines' coils, and for size and economy, these devices do not have heavy enough wire to take such a load.

By using the discharge unit, current used is FAR beyond the rating of the machine but works for so short a time that the "volume" of heat created in the coils cannot become excessive.

A discharge unit is not difficult to build from scratch provided one remembers to observe polarity when plugging in the capacitor. Capacitors used for such devices -- usually on the order of 1,000 to 2,000 mfd -- are "electrolytic" (only one of the plates in the device is competent to take the charge). If the polarity on such a device becomes reversed, the electrolyte will boil and the capacitor explode.

For route control, a diode matrix can't be beat. The diodes are arranged in logic groups on the TRACK side of the pushbutton, so that when one button is pushed for a selected route, all the relevant turnout coils get their jolt of juice. A diode matrix can control everything from a single crossover to a complex yard throat (just make certain the capacitor selected for the discharge unit has enough of a rating to be able to handle the maximum number of switch machines in any possible chain).

[Anonymous]

I don't use switches at all. I simply set up a schematic on a sheet of acrylic (hardboard will work too) with machine bolts at each switch location. I use a hot probe (I used a 1/4 inch phone plug that I had laying around but any metal thin thing like a nail could be made to work). The probe is attached to the same circuit as the hot (common) line on the turnouts. In operation you just touch the head of the machine screw on the line of track you want to go to. That activates the turnout to move the train to that line. I find that a pair of nuts on the machine screw (its really a fine bolt) will hold bare wire from the switch machine but a crimp on terminal of some sort is a little more elegant. Just as with a switch you only want to touch the head of the machine screw. You can burn out a machine if you hold the probe on the head of the machine screw but the tendency is not to do that. As a Scot by ancestry and nature I find this a much less expensive solution.