Need help with a wiring question/relay

[btaylor]

I need some help,I am wanting to wire some yellow led lights into my track walls, to signify a caution when the power is knocked out due to a track call . (trackmate system) It was easy enough to figure out the green lights as they go off and on with the track power, However,where in the world can i pick up power when the track power relay is in the off position?.
off course i want the yellow to go off when track power comes back on. anyone have any ideas?
http://www.ebay.com/itm/310954071636?va ... 1497.l2649
thanks in advance
Bob

[HomeRacingWorld]

C'mon electrical wizards...there is an answer? :)

Try emailing the folks at Trackmate. He might have a lead (get it?) for you.

[btaylor]

[HomeRacingWorld]

I'll be here all week! Try the veal :)

Good counter....well done!

[btaylor]

I took your advice and dropped them a wire, :oops:

[btaylor]

For future reference,Anyone using a trackmate interface system,that wants to to turn on any other 12 volt accessory.
when the track power is off,can do so by using this little unit right here.
it is brand name, BWD (Sold at NAPA) PART #R3177
This is a 5 pin normally closed relay. it allows power to run through the contacts After energizing power is removed.{track power wire} At that point it will turn on your accessory,in my case flashing yellow lights signifying caution. when track power is turned back on, the yellows go out and the green lights come back on.
If used in conjunction with a COBO brand transistorized flasher relay,you can make the yellow lights flash when on, when using 12volt LED bulbs. Just tap into the positive wire that turns on your yellow lights.
This may not be needed by a lot of folks,but the info is tough to get! thought i would share just in case,as it does work.

Bob

[RichD]

This will work, the relay coil would be connected in parallel with the coil of the track power relay. Use yellow LEDs in place of the red LEDs. The values for the R1 and R2 resistors would have to be adjusted for the track voltage that you are using. If you expect to vary the track voltage at the power supply you should use a separate power supply for the LEDs. Green and yellow LEDs operate at different voltages so the values for R1 and R2 would be different.



If you used 117VAC lamps instead of LEDs you could power them directly from a wall outlet. You would need to be careful about exposed wiring when using 117VAC.

[btaylor]

Thanks Rich! I will be using a separate power source for the led's, i had thought about the fact that i will be varying the voltage now and then.
In fact,i can use two different power sources if the Leds's require different voltages. both could be triggered by the TPR?
I also wanted to keep as much under table wiring in the low voltage range.
Bob

[RichD]

The coil of the relay for switching the lights would be connected the same way as the track power relay. Red LEDs usually run at 2 volts or a little more, yellow LEDs run at 3.5 volts if I recall correctly. The LEDs will burn out immediatly if the voltage is 1 volt too high and even a half of a volt too much will shorten their life, so you will have to be careful. Look up the current and voltage specs for the LEDs that you intend to use. Unless you intend to use adjustable power supplies to power the LEDs you will need to measure their actual voltage output under load, that can often be different from their nameplate voltage. I bought a 12 volt regulated power supply to power my track lights, but it was actually 13.8 volts. My lights would have gotten cooked if I had used that power supply without adding dropping resistors. Here is a calculator for sizing resistors: http://www.quickar.com/noqbestledcalc.htm