Can a Tortoise Switch run on AC?

Model Railroader Electronics and DCC
1

Can a tortoise switch run using AC current?

If this is possible what will I need to convert AC to DC current in order to make the tortoise work.

Thanks in advance.

Alez

2

No, the drive motor is DC only. You can use a pair of diodes to rectify the AC, diagram here:

https://ogrforum.ogaugerr.com/fileSendAction/fcType/0/fcOid/26349031919048951/filePointer/26349031952843887/fodoid/26349031952843882/imageType/LARGE/inlineImage/true/Tortoise_using_AC.PNG

Or you can just get a cheap 9-12V DC wall wart and use that to power them. A 1 amp wall wart will run over 50 Tortoises. A half amp (500ma) one will run 25 Tortoises.

–Randy

3

Unless you get a multi amp 12v power supply for these and lighting, just use a 12v 1A walwart. Add a 3/4A inline glass fuse and operate 30+ Torti. If you add series LED indicators the Torti will see about 9v and move at a moderate pace.

CORRECTION: My Circuitron walwart is 1/2 amp, which can power 30 Torti.

4

As was said DC only. I put a two lead bi-polar red green LED in series with one lead to indicate path. No resistor needed.

Instructions below.

http://www.circuitron.com/index_files/INS/800-6000ins.pdf\

Rich

5

Since DC power supplies are so readily available, why would you even consider trying to modify the Tortoise to run on AC power?

Rich

6

you can use a 12V AC supply with “steering diodes” to produce half-wave rectified +12 and -12. sorry - see randy already mentioned this

this avoids needing a 2nd supply and probably cuts the current in half

7

I seem to recall an article where someone used an AC “center tapped” transformer to run tortoise switch machines.

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The point was that you could use a SPDT switch to run the tortoise this way rather than a reversing DPDT switch as typical, so wiring would be simpler.

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It seemed like a solution to a problem that nobody had. DC power supplies are plentiful and easy to obtain. I have used the same MRC Tech II 1500 to run the tortoises on 3 layouts so far, and intend to use it on my next one. I use the “track output” so I can adjust the speed to a point that seems best.

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-Kevin

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8

Hello

I am trying to install crossing gates using a tortoise. As the speed of the train slows down so to do the gates to the point of not moving at all, the train still crawls along.

I realize the speed of the crossing gates is based on how much power is coming from the power pack to move the train.

I have a 1A wall watt and like the idea of separating the tortoise DC from the main line DC.

Could you explain more about setting up the wall wart with an inline glass fuse.

I am fairly new to electronics of model train but am determined. Run DC trains.

Thanks in advance.

Alez

9

I use a 12v DC walwart, in my case the 0.5A DC output one that Circuitron sold in 2012. It has 2 output wires, perhaps to a small plug that gets cut off. The 2 wires go to barrier strips, which I use as the 12v connection source for each Tortoise. It is advertised as able to power 30 Torti.

http://circuitron.com/index_files/Tortoise.htm

Note: I used similar “regulated” 12v 1A walwarts for my 3 LED lighting circuits. So I would have been better off buying one 5A power supply, which would be more reliable than the walwarts (I think).

In ONE of the wires from the walwart, cut the wire and connect to a glass fuse holder such as this. Note this one is for 1/4" x 1-1/4" glass fuses.

https://www.radioshack.com/products/radioshack-chassis-type-fuse-holder-2-pack

Insert a 0.5A (no more, ideally a tad less) FAST-blow glass fuse, of correct 1/4" x 1-1/4" physical size.

https://www.radioshack.com/products/radioshack-0-5a-250v-fast-acting-1-x-glass-fuse-4-pack

Here are the barrier strip types I added to my control panel. I put one above another one, so one was positive and the other negative.

https://www.radioshack.com/products/radioshack-8-position-dual-row-barrier-strips

Note that each pair of terminals is separated, so to make the whole strip common (DC plus or minus), “jumpers” are neede

10

Alez Auto stores have both inline fuses and fuse holders. They look a little bit different than the one posted above in that they are enclosed in a little plastic cylinder.

Here in the US, Radio Shack used to be everywhere. They have declared bankruptcy 2 or 3 times and the nearest stores are now 90 minutes away in small towns.

11

Paul

Do I need to attach a fuse if I only plan to use this wiring to run the tortoises ?

Thanks

Alez

12

OK… Help me out understanding this…

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You say you are using the same DC for the Tortoises that you use for the track power.

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If you change train direction do all of your tortoises switch to the opposite route?

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How does that work?

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-Kevin

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13

I have not but it is your choice. Just cut one wire from the power pack and insert the fuse. No big deal.

Rich.

14

The trouble with wall wart supplies, and even other larger supplies we use, is that they don’t have circuit breakers or fuses of their own. So, if you accidentally short or overload the supply, it will become an ugly paper weight without much other value.

You don’t need a fuse, really, but a fuse is cheaper than a new supply.

15

The key questions are:

a) whether you can guarantee you will not short something in your wiring; e.g., when hooking things up (best to have the power off then) and/or when you turn it on and have miswired something

b) whether you prefer to install the fuse to preclude possibly having to change out a bad walwart due to an error, versus the trouble of installing the fuse

Same for Tortoise wiring or lighting wiring. Do you want to take the risks or add the fuse that limits the walwart output pretty quickly, hopefully avoiding the damage. Depends perhaps on how conservative one is, definitely my leaning.

BTW, suggest to get a booklet on model train wiring to understand the basics. It would not go into the detail above but be a foundation for issues that you need to address. Everything you need is available on free websites but they can easily overwhelm with volumes of detailed info, so I suggest a starter book. Perhaps one of the folowing. If not planning to go DCC, perhap’s A. Sperandeo’s “Easy MModel Railroad Wiring”. The current Kalmbach "Wiring Your Model Railroad (Essentials) gets into DCC also.

https://www.amazon.com/s/?ref=nb_sb_noss?url=search-alias%3Dstripbooks&field-keywords=model+railroad+wiring&rh=n%3A283155%2Ck%3Amodel+railroad+wiring

16

I’m going to attach an inline fuse holder to the 12V 1 Amp adapter wire, but at the moment I only have a 2 amp fuse available.

Will this fuse be to large and does it matter which wire the fuse holder goes on?

Thanks

Alez

17

No, you need a fuse no larger than the current rating of the supply, and preferably a bit smaller to give you some margin. For a 1-amp supply, use a 3/4 amp fuse. The voltage rating of the fuse is a maximum, so it’s probably not going to be a problem.

18

Either wire. The electrons are just flowing from and back to the walwart, through the wires, barrier strip, DPDT switch, LED (if there), the Tortoise, the fuse, etc. The fuse can be anywhere in series. If it is intact, the flow is just going through it. If it blows, the wire inside burns to open up, so there becomes a gap in the circuit and the flow stops. It does not matter where the gap (fuse) is as once the fuse is not intact, the circuit is open and electriicty flow stops.

19

Ok, all is good. I have attached an inline fuse holder with the correct fuse to the Wal wart and even attached a DPDT switch. The tortoise runs great forward and backwards.

The next question I have is there a simple devise that will slow the tortoise down.

Thanks for the help.

Alez

20

A LM317 voltage regulator, couple resistors, couple capacitors. Use resistors to set the regulator at nine volts DC or get a nine volt wall wart. Some have done both. Online calculators for setting the regulator.

I have used these regulators many times for different voltages.

Rich