I'm attempting to build a 12v fan and I'm looking at controllers to drive the 3 phases of the motor. It seems every ESC i find has a potentiometer included. I want my fan to always run at full speed and be turned on by a simple relay.

Can I just short the positive and signal legs on the board in lieu of connecting the pot in order to simulate a pot at 100%?

  • \$\begingroup\$ What does the data sheet for the BLDC motor suggest is the correct way to power/connect it? \$\endgroup\$
    – Andy aka
    Sep 8, 2018 at 10:22
  • \$\begingroup\$ Unfortunately there isn't one available. It's a proprietary motor on a car. The control board failed and i'm attempting to use a cheaper, common alternative as a replacement for just the board. \$\endgroup\$ Sep 9, 2018 at 8:42

1 Answer 1


If you have an ESC that is suitable for the motor you can use it without a potentiometer by connecting the potentiometer input to the terminal that would normally be connected to the clockwise end of the potentiometer. Check the ESC information to be sure that the CW end of the potentiometer is normally connected directly to a terminal.

You also need to check the ESC information to determine how the motor is started and stopped. Your start/stop relay must supply that command. It is unlikely that you can start and stop by connecting and disconnecting the motor to the ESC or the ESC to power.

It might be a good idea to start with the ESC connected exactly as recommended using a potentiometer. Make sure the motor runs well and then change the speed setting method.


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