Not Right

If I understand your schematic correctly I see short circuit when the switches are pressed. You have the power supply connected to each side of the switches.

In the second diagram the solenoids have continuous power. At least until the switch is closed and shorts eveything out.

+ +

Here is the correct wiring for 2 switches/1 turnout

Marc Fournier, Quebec

Beat me to it

I was doing the same Photoshop rearrangemnt of his drawing when I saw your post come on. Marc's got it Paw.

Here is my take on the three

Here is my take on the three switch  / two sol.  And do not use AC.  Use DC power.   .

Now did we win anything ....

Marc Fournier, Quebec

Once the turnouts are thrown,

Once the turnouts are thrown, is there someway to tell which route is selected (besides looking at the turnout points)? A problem with pushbutton control is that without some extra circuitry and LEDs (or lamps) you can't tell, from a control panel, what the selected routes are.

Charlie

That probably explains the

Thank you to everyone who took the time to respond.

LKO, that probably explains the burning smell...

Marc, my undying gratitiude.  Thank you very much for going above and beyond with the diagram.  Drop me an email some time soon.

George, I'd read a little about diode matrices but as you might imagine from my short circuit above, the more I read the more I realized that I could pronounce the words but still got no meaning.  Only two turnouts will be controlled at any one time.  But protecting the turnouts would be a good thing.  Sigh.  I keep telling him that scenery and structures are my thing and I keep getting sucked into wiring.

Charlie, no.  No indicators.  The layout is only 5' x 8'.  If I understood wiring, then I'd probably add in the extra bonus of lights and the capcitor discharge but I'm hoping that the switches will do the trick.

Again, thank you all for your help.

Cheers,

Michael

Twin Coil Control

I think this is one of the best Twin Coil Control options I have seen.  Momentary burst of power, no danger of burning out switch machines.  Route indication from toggle position and the ability to add illuminated indicators easily. 

twin coil control

Several comments after reading all of the responses.

AC or DC does not make any difference in this simple system.  AC has the advantage of buzzing when the power is applied to the solenoid--an audio indicator that something is amiss.  I don't see any necessity for a diode matrix or more complex system so DC is not necessary for the layout as drawn.

When switching a crossover, two of the buttons need to be in parallel so both buttons throw both coils for the straight route.  As shown in the diagram, the two green wires from the buttons need to be tied together.  Otherwise ech of the outside buttons will only throw one of the solenoids.  No electrical issues tying buttons in parallel as the buttons are open circuits unless depressed.

Current rating for the buttons is an issue.  Use buttons with at least a 2amp rating on the contacts.  Contacts with an inadequate rating will work for a while, but will fail earlier and more often.  The failure mode is normally a short with the contacts welded together.

I believe there are toggle switches with momentary contacts that contact as the toggle is thrown,  but do not keep making contact when the lever is in the detent thus giving an indication of point direction without having a more complex system.  This needs to be researched as I have CRS (can't remember anything) and the last I looked for this feature was years ago.  Other simple options require the addition of contacts with a mechanical connection to the switch machine.

The way I run on a railroad without turnout indicators is to press each button on my route or look at the points.  I also try to use some discipline to remember to throw the turnout back to the normal route after I use it.

Terry Roberts

About the twin coil control

Very good, Kevin. After examining this briefly (device 751D), I am convinced the circuit is of excellent design. For $8.00 each, Ken is selling them for almost no profit. His claim is that they are fully tested before shipping - that is a plus. In addition, his circuit provides for remote connection of LEDs to indicate the position of the points on the turnout.

@Terry - About using AC - you are correct that it will work and perhaps the buzz will give some audio feedback on the power status of the switch machine, but the use of DC would be quiet and the advantage is that an electrolytic capacitor could be employed for a capacitive discharge type powering of the switch machine (use of a large capacitance gives the switch machine all the energy it would need while not allowing a continuous powering of the solenoids). An added advantage of using DC power is the ability to put a diode across the coils so as to absorb the high voltage back EMF generated by the coils (often it is this back EMF that causes arcing in the switch, resulting in the fusing of the contacts).

The Atlas Deluxe Under Table twin coil switch machines (model #66) or equivalent have additional contacts to use for LEDs to indicate the position of the turnout points.

Electronic Turnout Switch (751D)

For those who are comfortable working at the component level, soldering circuit boards,  Ken also offers a 10 pack that includes one assembled kit and 9 unassembled kits for $4 each.

I second: diode Matrix - plus

Kalmbach: Wiring for DC (or similar title) explains a diode matrix... Oh, also consult NMRA on Any subject you need background in... they let us see lots of their good ideas.

Plus a Flip-Flop circuit operating position indicators.

 I'd like to see a modular solution to my 2nd suggestion: - Wish Answered! See Kevin's post above... looks good and should do Exactly what I had in mind.  (thanks Kevin!)

It would work with my wiring... Use Double pole- double throw Momentary contact switches ... use one pole as diagrammed above to control turnout motors.   The other pole (in my case) is reserved for a simple flip-flop circuit to control the display of LEDs.   Thus, push switch lever up : throws turnout and changes lighted indicator.  Using 2 circuits makes the operation of lights independent of current through the coil (which would overheat it).

About the twin coil control

Bill,

I agree with your comments. However I was going for simplicity. Some of my rationale:

Two atlas coils isn't much of a load and should be easily driven by a 1 A supply.  The buzz is a warning if someone leans on the control panel or something else happens.  If a DC supply is available use it.  If it's AC use it.  No need to spend more time or money.  As an aside, pulsed or unfiltered DC will buzz or sing at you.  DCC running a DC locomotive is a prime example.

In this simple layout there is no need for a diode matrix.

I built a cap discharge supply for the Mt Hood Model Engineers (Portland OR) with a really big capacitor and a current limiting charging circuit.  The biggest problem we had was breaking the mechanical linkage on the twin coil machines--one can go too far with a good thing.  We had one push button failure in the 15 years I was associated with the club.  We did not have any reverse diodes in the system.  I used 2A 250V push buttons in the design. 

I'm not sure which is worse for a switch, the make,break current or the high emf spike.  I know I would take both into consideration in a commercial design.

Enough rambling for now--gotta go play "gofer" for the fire chief.

Terry Roberts

"I think this is one of the

"I think this is one of the best Twin Coil Control options I have seen.  Momentary burst of power, no danger of burning out switch machines.  Route indication from toggle position and the ability to add illuminated indicators easily. "  Kevin Rowbotham ...

Kevin,

Thank you for pointing me towards Ken Stapleton and his Twin Coil Controls.  They appear to be just the thing to solve my particular problem.  When I get them in place, I'll post a photo and let you know how they worked out.

Again, thanks to everyone for taking the time to offer your thoughts on the best way to solve the problem.

Cheers,

Twin Coil Controls

Michael,

Happy to be able to help.  I look forward to seeing photos of your installation.

Has anyone been in contact

... With Mr. Stapleton?   I don't know if I have the problem, but my email bounced.

(Maybe I need to use my alternate account.)

Here's hoping he's still building these!--

subsequent edit:

 cool, I'm off on a short trip, so I'll be looking into your results... and will likely follow up when I return. 

-Peter

Contacted...

Michael has been in touch with Mr. Stapleton to place an order I believe but I'll let him elaborate on that if he wishes.

Yes, I went to Ken's site and

Yes, I went to Ken's site and exchanged a few emails about what I was trying to do.  Ken was extremely helpful and I've made an order.  When the order arrives and I've made the control panel, I'll let y'all know how it worked out.

Cheers,

Michael