Batboard

I am looking for a schamatic for a fan speed controller. I have tried adding a thermostat(93-107 degree) sensor to the heat sing. It starts but then never turns off.

I think I would be better off using a thermistor on the heat sink and a speed controller.

The fans are 12 volt.

Any sugestions appreciated

Mark
KB1IOZ

Use a 2-speed timed setup.

Run the muffin fan through a 20 or so ohm, 20 watt resistor for low speed and run it full time at this speed.

Add an ELK960 timer board and connect the N.O. relay contacts across the 20W resistor. Now take the PTT/transmit lead and run it into the ELK timer's trigger lead. Set the ELK timer at 30-60 seconds.


The fan will run at about 1/2 speed all the time. When the unit transmits, the ELK timer will bypass the resistor for (X) seconds and run the fan at full speed.

Works great.

Yes I guess having the fan run at a slow then switching to hi during tx makes sense. Many PA problems are caused by heating and cooling and the related expansion and contraction.

So it makes sense to try and keep it from getting hot in the first place.

Thanks
Mark
KB1IOZ