Does anyone know how to wire a switch master using a Red and Green LED. The way I have it wired both LED's stay on all the time. I'm using a DPDT switch.
First, welcome!
I can only speculate as I have Tortoises run with DC, about 12v. My 2-leg bicolor LEDs are wired in series into one of the DPDT outlet wires to the Tortoise. The LEDs provide about 2v drop so the Tortoise sees about 10v. No resistor required in that setup as the voltage is in the range for the Tortoise. The LED switches color as the DPDT switches the polarity it and the Tortoise see. Don't know if this analogy will help with your SwitchMaster setup.
Are these separate versus bicolor LEDs. If separate, are both lit when powered in one direction and neither lit when the switch is thrown the other way? If so, one needs to be reversed so it lights when the polarity is the other way.
If bicolor, are you powering with DC, what voltage to the circuit, where/how is the LED (2 or 3 leg) wired in, using a resistor in the circuit? May help someone knowledgeable with these to see the problem. I see they provide a 1200ohm resistor for taking 9v of a 12v supply, leaving the spec 3v for the motor. If adding a LED (or two in parallel, reversed polarity), the resistor value I presume should be reduced to take approx 2v less drop (i.e., 7v) and allow 5v for the LED plus motor. But I kinda doubt that is why the LED(s) has both sides working.
Or try e-mail with the vendor (no phone number on the link below). But someone here can likely clarify pretty soon.
http://www.builders-in-scale.com/bis/sm-home.html
Paul
Modeling HO with a transition era UP bent
Just connect one of the wires from the DPDT switch to the bi-color LED between the toggle switch and the switch motor.
The LED will be very dim as the motor is moving, but will brighten when the motor reaches its stall position.
Attached sketch is from Switchmaster Instructions, power source 12v, resistor value 1200ohm.
regards, Peter
Oops, Sorry, revised sketch, guess I'd better get some more coffee in
Peter,
First I assume your power source is DC. (In fact I don't think a Switchmaster would work, otherwise.)
I am not enough of an electrical engineer to explain why your set up doesn't work. But what I suggest is that you wire the LED's in series rather than in parralel as drawn. You will want to have a pair of the LED leads, either both short or both long, facint each other. That is if say the long lead is A and the short lead is B you want them wired A-B-B A or B-A-A-B.
Belt and suspenders: one wire will go from the DPDT switch, then to the LED's wired as above, then to the Switchmaster. The other wire goes from the DPDT switch directly to the Switchmaster. You should not need any resistors as the switch motor will provice adequate resistance to protect the LED's.
Disclaimer: This is how I have wired a couple dozen Tortoise machines. I am aware, however, the Switchmasters have a much higher current draw (amps) than the Tortoises. I don't think that changes the LED wiring but if it does hopefully someone smarter than me will pipe up and say "Roger's nuts!"
Good luck.
jrbarnes,
The sketch I posted earlier today was drawn from Switchmaster Installation Instructions REV. 2/91, Figure H Accessory Wiring, this works just fine assuming you have the correct valued resistors for the DC power source. There may be more and better ways to panel light Switchmasters, but I followed the Mfg. instructions back in 1992. BTW, as you probably already know, the motor requires it own resistor.
Do you need panel indicator lights? Most my buddies and I use switchmasters and none of us have panel lights. We just let the toggle indicate positon of the switch points on the pamel. Very simple an much less complicated to wire.
Guy
see stuff at: the Willoughby Line Site
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