I have installed tortoise switch machines on my layout and now I'd like to put in some Tomar G/R dwarf signals to be controlled by the tortoises. I have done preliminary wiring on the tortoise's - positions 2,3 & 4 for the signals. These are all connected, along with the 1 & 8 power positions, to a terminal strip for each tortoise. The tortoise's are powered/controlled by Digitrax DS-64's. Questions - will I need a separate DC power supply for the signals? I have one ready. Do I need to put resistors on not just the red and green LED leads but the common as well?
If anyone has experience with this type of setup I'd appreciate your help.
Dave
'there's something happening here, what it is ain't exactly clear' Modeling the Hard Knox Valley Railroad in HO scale http://photos.hardknoxvalley.com/
No extra built in resistors in a tortoise. The current draw of the motor is limited by its inherent impedance. The current through the LED cannot exceed that of the motor. Luckily the draw through a tortoise is pretty close to perfect for an LED.
A two lead bipolar LED simply goes in series with either #1 or #8. Reverse leads or orientation of the LED and color changes. For a three lead LED you should be able to use just the two outer leads. I am not familiar with the Tomars. If four wires just treat them is in the diagram linked in David's post.
Experiment a bit. LEDs are cheap.
Karl
The mind is like a parachute. It works better when it's open. www.stremy.net
With some help from a thread on the Trainboard forum I was successful in wiring up my first signal last night.Here's what I did in case anyone else is planning to run Tomar dwarf signals from tortoise switch machines.I used a separate DC power source - a PS-12 to be exact, although the folks at Tomar told me I could use an old power pack. If this were the case and all it had were the variable DC connections they said to just turn the throttle all the way up.Anyway, using the PS-12 I snipped off the connector on the end and split the wires. I attached them to individual terminal/barrier strips. The common from the signal attaches to the DC negative strip and the number 4 (in my case at least) position on the tortoise is wired to the DC positive strip. The red and green wires from the signal (be sure to use the resistors recommended by Tomar) go to the 2 & 3 positions on the tortoise. You just reverse the 2 & 3 position wires if the signal lights don't match up with the direction of the turnout. If you pre-wire the tortoise to a terminal strip before installation this is pretty simple. The end result is very cool, the switch moves and the light changes color. Also, I have to say, having used many different types of dwarf signals in the past - mainly NJ International - the Tomar signals are the best I have come across.
Dave [:-banghead]