开云体育

Don,

So you have temp sensors that turn off when they get hot, and a bunch of extra IRF510's?
An excellent opportunity to better understand what an IRF510 does!

Here's the data sheet:
??

Assume we tie the SOURCE pin of the IRF510 to ground, the DRAIN pin to one side of your fan, and the 12v line to the other side of the fan.
When the IRF510 conducts from DRAIN to SOURCE, the fan will be working.

How do we tell the IRF510 to turn on?
We raise the GATE pin from zero volts (measured with respect to the SOURCE pin, which in our case is the same as ground)
up to maybe 12 volts.? You want 5 volts to turn it on good, anything over 20 volts on the GATE can destroy the IRF510.
So if we tie a 1k resistor between the 12v power supply and the GATE, the IRF510 will turn on and the fan will spin up.

How do we get the IRF510 to turn off?
We can now just short that GATE pin to ground with a wire, that puts 12 volts across the 1k resistor and we waste a measly 12v/1k = 12 milliamps of current.

How can we use your normally closed thermal switches to short the gate to ground when the thermal sensor cools off?
Just tie the thermal sensor between the IRF510 GATE and ground.
When the the thermal sensor gets hot, the switch inside opens up, the GATE is no longer shorted to ground
and so the wimpy 1k resistor can pull the gate up to 12v, which turns on the IRF510, which allows current to flow through the fan.

As a bonus, if you ever blow the IRF510's in the uBitx main board, you know where you can find a couple spares.


30 Watts out?
That's way too much.
The rig is probably distorting badly, and you are seriously in danger of destroying your uBitx.

Jerry