Controlling Tortoise Switch Machines

[Big Train]

Any opinions about controlling a Tortoise switch machine with DPDT switches? Specifically pros and cons about using a momentary centre off switch [(on)-off-(on)] or a thrown [on-off-on] type? After using the solenoid type (Tenshodo/NJ International/Park) for so long I thought using the momentary DPDT seems a natural choice, but I'm not too sure if it's appropriate now that I see a Tortoise in action. It seems you have to have the "timing" just right with a momentary to ensure the points stay in position before it rebounds off the stock rails.

Would using a thrown type keep the motor inside the Tortoise energized?

Thanks!

[LKOrailroad]

[(on)-off-(on)] NO
[on-off-on] YES
Tortoise is a stall motor. It is designed to have current flowing continuously. The stall action assures the points are fully thrown and held tight against the stock rails. If you like the operation of a momentary switch (as I do) see this post: http://www.lkorailroad.com/tortoise-control/. Look specifically at update #3. My arrangement utilizes one set of the Tortoise internal switches so that I may use a momentary push button. You could use a momentary SPDT instead of the Tortoise switch to actuate the relay if you want the flip up/flip down feel.

[peteski]

Big Train, have you actually read any of Tortoise's literature (like installation instructions or wiring)?  It is a stall motor machine which is designed to be continuously powered.  Without any power its actuating arm could actually creep towards the center.  The feature the it is always powered is often utilized for indication its position while only using 2 wires going to the switch machine.

Even without reading the manufacturer's literature, just do a Google search for tortoise machine circuit (or similar search) and you'll find many examples.

[Big Train]

Thanks for the responses. Never encountered a stall motor before. The instructions did say "Any type of DPDT switch....can be used."

[jagged ben]

Tortoise is a stall motor. It is designed to have current flowing continuously.

It may be designed for continuous current, but it functions just fine without it. 

We have hundreds of turnouts at our club that are operated through momentary push buttons.  Some are controlled through decoders that are programmed to send power for 4-5 seconds.

The only issue with using momentary buttons is that you have to press the button until you see the points throw all the way, or usually about 5 secs.

The advantages and disadvantages of the various approaches are too myriad to go into. 

[nickelplate759]

An old topic, but it seems like the right heading for my question, so here goes.

I am looking for a small-ish double-push-button DPDT switch to mount in my control panel to control Tortoise switches.  Even better if I can mount an LED to illuminate the push buttons (switch doesn't need to control the LED's directly).  I want to have one button appear in each turnout route in the track diagram, so I'd like the buttons to be about 2 cm or so apart (needn't be exact).   Something like this crude picture where the buttons are represented by the circles (yellow is "lit").

Any idea where to find such a thing for not too many $$$?

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[peteski]

An old topic, but it seems like the right heading for my question, so here goes.

I am looking for a small-ish double-push-button DPDT switch to mount in my control panel to control Tortoise switches.  Even better if I can mount an LED to illuminate the push buttons (switch doesn't need to control the LED's directly).  I want to have one button appear in each turnout route in the track diagram, so I'd like the buttons to be about 2 cm or so apart (needn't be exact).   Something like this crude picture where the buttons are represented by the circles (yellow is "lit").


(Attachment Link)

I don't know of a source and I suspect that if you find one, it will be quite pricey (especially if the buttons are back lit).  It reminds me of the really old fashion household wall-mounted  light switches which had this sort of arrangement.



If you really want to go this route, I think it would make sense to use simple SPST momentary push buttons which would then interface wit some sort of electronic controller which would then drive the tortoise motor and the LEDs in the switches.

But while not as clean, a much simpler and less expensive solution woudl be to use individual LEDs and DPDT toggle switches. Here is how we did this on Ernie Poole's layout.









The LEDs are not even protruding through the clear control  panel, which is back-engraved, so it has a very clean  look.  The electrical wiring is a simple standard tortoise wiring scheme with the indicator LEDs in-series with the motor.  The DPDT switch reverses the polarity to throw the switch. The LEDs become dimmer as the machine is in motion, then become bright when the movement stops and the points are at rest.  That is a very handy feature.  The cost is minimal since 3mm LEDs and DPDT toggle switches are plentiful and inexpensive.   And the control panel IMO looks pretty darn good.

[nickelplate759]

Those old pushbutton wall switches were exactly like what I had in mind, but they are too large, and only SPDT, not DPDT.  I realize that there is a way to control Tortoises with only an SPDT, but still.  Also, they're not lit, and they tend to cost over $10 each.

I like the look of Ernie's control panel.  Thanks for the example.  I'll probably do something similar if I don't find a pushbutton switch soon.

Is that Cat5 (or maybe Cat6) ethernet wire?

[peteski]

Is that Cat5 (or maybe Cat6) ethernet wire?

Yeah, it was either standard 4-pair phone cable, or a CAT-something network cable. Back when we wired it up it was probably only up to CAT1.5. 

[Cajonpassfan]

Slick panels, Peteski.
Big Train, I used SPDT switches on the older portion of my layout, with color LED's fed through the Tortoises, see pics.
Also including wiring options FYI. I used #3. Fewer wires...
Otto K.

[nickelplate759]

While we are on the topic - I noted above that Ernie's control panel used something like Cat5 (or maybe thermostat) wire.   This is usually about AWG 24.
Since Tortoise current draws are pretty low (Circuitron says 16ma at stall), am I correct in assuming that even 20' or so (figuring up to 10' from the Tortoise to the switch)  runs with such small wire (although I'll probably use AWG 22) are not a problem?

[peteski]

While we are on the topic - I noted above that Ernie's control panel used something like Cat5 (or maybe thermostat) wire.   This is usually about AWG 24.
Since Tortoise current draws are pretty low (Circuitron says 16ma at stall), am I correct in assuming that even 20' or so (figuring up to 10' from the Tortoise to the switch)  runs with such small wire (although I'll probably use AWG 22) are not a problem?

Correct. No problems with voltage drops on Ernie's layout.  We also seem to be over-designing our track feeders. I posted my opinions on this subject in this thread along with some sample wire resistance charts.

While not specifically showing the 16mA draw, I do include 24 AWG wire in those charts. You can easily calculate voltage drop of 20mA (for ease of calculation) on whatever length of 24 AWG wire you will be using.  Just use the 12" chart and the 2A current and move the decimal point to get 0.020A (20mA).

[nstars]

Those old pushbutton wall switches were exactly like what I had in mind, but they are too large, and only SPDT, not DPDT.  I realize that there is a way to control Tortoises with only an SPDT, but still.  Also, they're not lit, and they tend to cost over $10 each.

I'm not sure, but I think that alpha system from DCC Concepts is doing exactly what you're looking for.

Marc

[ChrisKLAS]

If you want to use a pushbutton instead of a toggle, you can interface the Tortoise motors with a Digitrax SE8C (or similar) board. Each press of the button will throw the points to the opposite position and keep them there. I use that method for some of the switches on my industrial spurs.

For hand-throw switches that touch the main, I wanted a more prototypical solution so I'm using a Timelock circuit from Iowa Scaled Engineering (http://www.iascaled.com/store/CKT-TIMELOCK). This neat little gadget allows you to keep the points locked for the main unless a key is turned and the system has run time (amount of time before they unlock is customizable). It also provides a facility to shunt the track block when unlocked, which turns both signals at the end of the block red and illuminates a track light on the dispatcher's board. It may be a little bit of overkill for a model, but it is fun to play with and offers the added benefit of slowing local crews down a touch.

[mmyers]

Touch toggles from Berritt Hills Shops http://www.berretthillshop.com/