Reduce Fan Speed With Resistor

3 pin male to female.

Reduce fan speed with resistor.

3 pin male to female resistance. Designed with a resistor on the cable. However the motor will draw more current when starting up and as the load increases causing higher voltage drop and reducing speed even more. I have a 5v usb fan and i want to reduce the speed.

Quite practical and useful. This highlights one potential pitfall of this method you can t safely use 1 4w resistors for this unless you make up the target resistance using several smaller resistors of equal value in series. The only thing that has to be done is to connect a resistor in series with the power supply of the fan. Emmawatsun sep 20 2018 6 48 am in response to rayjai you should put a big size resistor on the 5 volt side.

The resistor will cause a voltage drop across its leads. Among all circuits i have make this is the simplest one. Use the 3 pin cable to connect the power supply to your cooling fan it will reduce the speed of the fan and cut the noise output dramatically. This voltage drop will be subtracted from the overall voltage on the fan and therefore the voltage across the fan will be reduced.

Quite practical and useful. If the motor draws constant current then the resistor will drop a constant voltage and the motor will run at a fixed lower speed. In our psc example we would likely have had to slow the fan speed by 7 15 to give us the ability to get much closer to our target of 350 cfm ton. Designed with a resistor on the cable.

Ecm motors typically offer all the same speed adjustments as psc s with the added ability to reduce speed in smaller increments from the low medium low medium high and high settings.