Just installed a G3 in my K-36 and I believe the temp inside the tender could be getting a little warm. The G3 instructions say I can install a 12V fan and I have a fan from my C-19 that was removed but the instructions doesn’t say how to install it. The main battery is 14.4V
My fan is 12v 0.09 amps
Any ideas on how to install this without burning it up?
Thanks
Bob Russell
There is a section in this forum for “Electrical, Electronics, and control systems”. You might get a better responce, if you posted your question in the proper section…
If you put the two fan wires directly into the motor output of the Airwire board, the fan will speed up and down with the motor. The only time the motor leads get 14.4 volts is when you are wide open. I run 12 volt LEDs on all my engines like that with airwire. And havent burned up the lamps yet. But I never run WFO anyway. Just remember the fan will reverse when you reverse the loco, so check it out before you button it up.
I was thinking the same thing. motor control.
Actually, the output to the motor is PWM, which means it gets pulses of FULL voltage, not good for a fan.
I’d buy a 24v fan, and run it from the battery, will draw less voltage, don’t need high speed, and will draw less current.
Greg
p.s. not all fans will run in reverse with reverse voltage… most won’t
The modern small fans are not motors tied directly to the power source, they have electronic circuits inside to control the speed.
I wouild assume an inexpensive fan would not have reverse power protection, hence a one time smoke generator!!
Greg, Thanks for your suggestion to use a 24 volt fan. That worked perfectly. I am converting several of the new MTH F3s with DCC capability over to 18.5 volt battery power. I installed an Airwire Convrtr-60 receiver which works very well but was running very hot inside the cab. I was just trying to figure out how to install a 12 volt fan when your suggestion came across on LSC. I installed it right from the battery, after the on/off switch and it solved the heat issue perfectly. As you said it doesn’t run at high speed, but it doesn’t need to…just creating a gentle positive air flow across the board is all it needed. Great idea! Thanks, Mark
Did a lot of research on fans, starting in 1978 in a small company called Hewlett Packard. Learned about boundary layers.
Most often just enough to break up the boundary layer near the heat producing element has the most effect.
Greg
That explains a lot. I wondered why the fans in a lot of equipment that I work on don’t run full blast most of the time.