I want to use SPDT toggle switches to control about 10 tortoises. A dual polarity supply is expensive but would two wal warts do just as well? What have others used?
73
Bruce in the Peg
Our club uses a 9 volt DC supply with DPDT switches. You could use two 9 volt supplies with the SPDT switches.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Bruce,
A pair of matched 'wall warts' with plus and minus tied together will work just fine for dual polarity. One 'plus' & 'minus' lead tied together are your common. Just make sure each wall wart is plugged in the same so you do not 'ground loop'. I have a 18VAC wall wart that I use, and have a pair of diodes to 'rectify' the output. This give me about 8VDC on each side and runs the Tortoise motors just fine. My 'wall wart' came from an old charger, and has a 850 ma output - enough for almost 50 Tortoise motors at 'stall'. Wall Warts are quite inexpensive on the Internet, and sometimes you can fine them for under a $1 at places like Salvation Army.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
Why do you need a dual polarity supply. Simply put the Positive and negative on the Normally Closed contacts. Then solder jumpers criss crossed to the Normally Open Contacts. The common wires go to the Torti. The single power supply will supply both polarities that way.
Springfield PA
Hamltnblue Why do you need a dual polarity supply. Simply put the Positive and negative on the Normally Closed contacts. Then solder jumpers criss crossed to the Normally Open Contacts. The common wires go to the Torti. The single power supply will supply both polarities that way.
He said SPDT toggles - no place for the crossed wire method there, which works with DPDT switched.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I guess his answer would be to use DPDT switches then.
Thanks Randy. Hamiltnblue, I have 25 SPDT toggle switches already. DPDTs cost money.
I like the idea of using an AC transformer with two diodes. It saves a wire from each tortoise to the panel!
But... does the half wave power cause any heating problems or noise?
They may but how do you propose hooking up spdt switches to a torti and having it reverse power?
You could do the same thing that is done in the US for 220 volt. A physical arm between the switches. You could glue a piece of plastic between the arms of 2 of your SPDT switches making it a DPDT.
Hamltnblue They may but how do you propose hooking up spdt switches to a torti and having it reverse power?
Two ways to do this. One is to use a pair of DC power supplies, hook the plus of one to the minus of the other and run that as the common to all Tortoise motors. The free plus to one side of the SPDT, the free minus to the other side of the SPDT, the center of the SPDT to the other motor contact on the Tortoise. SImple.
Or, AC power supply, connect a paid of diodes together on one side, anode of one to the cathod of the other. (stripe side and no-stripe side). COnnect this ocmmon to one sode of the AC supply. Other side of AC supply is common to all Tortoise motors. Free lead of one diode to one sode of the SPDT. Free lead of the other diode to the other side of the SPDT. Center of the SPDT to the other motor contact. Both methods are shown on the Tortoise instruction sheet that comes with them.
If you use say a 9V AC power supply, any noise or hum should be minimal. It's not really noticeable on a friend's layout and he has a 12VAC bus that powers everything with the diode method. Tortoises draw too little power to get warm. You can use a pair of 1 amp diodes and run a bunch of Tortoises, or do as my friend did, those cheap low power glass diodes that are in liek 100 packs and use a set of diodes for each toggle. Not sure what the rating is on those small diodes but they've been running his Tortoises for a couple years now.
Blind Bruce Thanks Randy. Hamiltnblue, I have 25 SPDT toggle switches already. DPDTs cost money.
Power supplies cost money, too, and extra wiring costs time and money. All Electronics has panel mount DPDTs for $ 1.85.
If you're replacing twin-coils and plan to re-use the SPDT toggles, think again. Twin-coils use momentary-contact toggles, whereas Tortoises want standard toggles. Make sure your SPDTs don't spring back to the center.
It takes an iron man to play with a toy iron horse.
The nice thing about this type of machine, you can put an LED in series with one lead and know which route is active.
At our club, we use bi-polar 3mm green/red LED's. Green is main, red is diverging. You can also use separate green and red LED's. No resistors needed with 9 volts. I think the machines draw about 25ma when using a 12 volt DC supply.
MisterBeasleyBlind Bruce Thanks Randy. Hamiltnblue, I have 25 SPDT toggle switches already. DPDTs cost money. Power supplies cost money, too, and extra wiring costs time and money. All Electronics has panel mount DPDTs for $ 1.85. If you're replacing twin-coils and plan to re-use the SPDT toggles, think again. Twin-coils use momentary-contact toggles, whereas Tortoises want standard toggles. Make sure your SPDTs don't spring back to the center.
..... Bob
Beam me up, Scotty, there's no intelligent life down here. (Captain Kirk)
I reject your reality and substitute my own. (Adam Savage)
Resistance is not futile--it is voltage divided by current.
SeamonsterI'm sure I'll get some disagreement here, but momentary switches could work. I have a couple of Switch Tenders on my layout and I've found that they hold the points against the rail quite securely when the power is turned off. I would suspect that any geared turnout control, including the Tortoise, would do the same because the mechanical advantage of the gearing is from the motor to the shaft, and that makes it hard to move the shaft against the gears.
I can say for certain that this doesn't work with Switchmaster stall motors (I don't use tortoise, can't comment). The points will move as the motors are unpowered. I have noticed that this is a random thing depending on the particular turnout (I have 70 turnouts) Some stay snug with no power, some don't. They will cause derailments if they don't hold the points snug against the stock rail.
RE Bi-polar supplies: I use the two wall wart system described earlier to produce a positive leg, negative leg and a common ground. I can use DPDTs to provide polarity to the frog and turnout throw from one switch. I use one speaker wire (or other 2 conductor cable) from the switch to the motor. Common ground buss wire around the layout gets a feed to the motor independent of the DPDT Works quite well for my application.
I recently upgraded my wall warts to regulated supplies to eliminate the voltage drop problems that were cropping up.
Guy
see stuff at: the Willoughby Line Site
In general, a Tortoise should have plenty of force to hold the points even when it is not powered. I've been installing my first half-dozen Tortoises, and before I had them wired to the panel that was certainly the case. However, this is going to depend on the geometry of the mounting, including how long the wire is, whether the Tortoise is well-centered below the points, and where the fulcrum is positioned between the points above and the driver below. The thickness of the wire used might also be important.
One thing I like about using a non-momentary toggle is that the toggle itself tells me the position of the turnout. I don't need a LED. With a momentary contact, I don't have that visual feedback. Also, a momentary contact with a Tortoise forces you to hold the toggle until the points are all the way over.
Tortoised will wok with momentary buttons, as long as you aren't using large code rail with all-rail turnouts (where the points aren't hinged - you literally 'bend the iron'). They can hold just fine against typical track with hinged points like Atlas. But the problem with pushbuttos in that unlike when used with a twin-coil solenoid motor, you have to keep holding the button untilt he Tortoise is thrown all the way.
Power supplies are CHEAP - do not EVER buy one from Radio Shack unless it's a life or death situation - they are so overpriced it isn't funny. I just picked up a couple of 14V 3A DC power supplies to use for accessories for $8 each. They're meant to power some small LCD monitors, but they are all over eBay for under $10, shippign included. Sure it comes from China, just liek my servos I use instead of Tortoises that I get for under $2 ea, shipping included. 14V at 3A is too much for a Tortoise but there are similar or even better deals on 9-12V 1-2A supplies. For the price of a single 12V supply at Radio Shack you cna get 3, maybe even 4, and have a spare on hand!
Go to Radio Shack and buy a 12volt DC 500 milliamp AC/DC plugin adaptor. They are cheap and will power 25 + "Torties" with no problems.
Split Reduction
You can use SPDT switches and a single power supply to control your switch machines. You will also need 2 resistors for each machine.
Rob Paisley has a circuit on his web site,
http://home.cogeco.ca/~rpaisley4/StallPower.html
Tom
I went that root when I first started building my layout and have since simplified all my turnout controllers by using Tam Valley Depots Quad Decoder. Th initial up front cost isn't all that bad $28.76 for the decoders you add in some fascia controls for $2.5 each (around the price for a DPDT mini toggle) and extensions if u require them. You draw power right from your dcc buss wires and your done. You now have the option to either control the turnouts via the fascia controllers and or by a dcc command form your throttle. I had to bite the bullet when I purchased my fist quad decoders like you I had pretty much everything I needed to start wiring up all my Tortoises .switch machines but soon realized that this system would save me a lot of money and aggravation and give me a lot more flexibility then wiring them up with a DPDT toggle
http://tamvalleydepot.com/products/quadservodecoder.html