I have a 230 Volts fan from EBM papst. It is a fan that can be controlled through a PWM signal (between 1 and 10 kHz). I have built the circuit that is in the manual (see image)
I did get this working using a 5.0 Volt arduino clone. I have been able to change one of the timers, so I am able to get a clean 4 kHz pwm signal on digitalOut 4. The fan responds nicely.
But I would like to get it working on another arduino clone that runs on 3.3 volt, currently I am getting no response at all from the 3.3V circuit.
The only thing I can think of that is different is the PWM voltage. The 3.3 volt arduino clone only makes 3.3 volt peak-to-peak, whereas the other arduino does to at 5.0 volt.
My question, can this be solved by choosing a different transistor? And if so, what specifications should I look for?
And otherwise, what other information is useful to know? I have some basic measurement equipment including a simple oscilloscope, but I don't know what to look for.
Edit: http://datasheet.octopart.com/R3G310-AI01-81-EBM-Papst-datasheet-15198448.pdf
Page 4, not the exact same fan, but the same schematic, could not find the correct one at the moment.
Best Answer
According to the above drawing, it looks like the fan wants to see a 0-10 volt swing on the PWM input (yellow wire) and will supply 10 volts DC on the Voltage output (red wire).
simulate this circuit – Schematic created using CircuitLab
If you simulate the above circuit, it looks like a 3.3 volt input to R1 should be enough to saturate the transistor and provide almost a full rail to rail swing on the fan's PWM input.
Can you verify that your connections match the above schematic?
Some tests to try...
Disconnect the pin from the input to R1 and use a wire to connect the resistor's input directly to the 3.3 volt power supply. Does the Fan come on full speed?
Now connect that same wire to ground. Does the fan turn off?
Attach a volt meter to to the collector of the transistor. You should see 10+ volts there when the input to R1 is connected to ground, and 0 volts there when the input to R1 is connected to +3.3 volts.