I have an ESC like in the picture and I want to test a motor with it. I don't have any PWM source. Can I connect something simpler (like a DC source) to it to make the motor rotate?

(Red arrow points input of interest but it's not obligatory)

enter image description here

  • 1
    \$\begingroup\$ please post ESC part number and link to its datasheet / documentation, if you want a more meaningful answer. // This is a little cheesy, i'm not a fan of the 555 nowadays, but here \$\endgroup\$
    – Pete W
    Commented Jan 26, 2021 at 13:34
  • \$\begingroup\$ "Red triangle" points ambiguously at three wires. \$\endgroup\$
    – JRE
    Commented Jan 26, 2021 at 13:53
  • \$\begingroup\$ You need to buy a servo tester \$\endgroup\$
    – DKNguyen
    Commented Jan 26, 2021 at 14:13
  • \$\begingroup\$ Even if you succeed in testing it with an other signal than is specified, you aren't actually testing what is was made for. Get a servo tester, or create a proper signal using a 555 or an Arduino or some such. \$\endgroup\$
    – ocrdu
    Commented Jan 26, 2021 at 14:17

1 Answer 1


No - Almost all hobby grade ESCs require some form of PWM (or digital, for multirotor ESCs) input in order to drive. As mentioned in a comment, you can make a "servo tester" with a 555 timer, or with a microcontroller to generate the waveform.

If you have the information for your ESC, it may be supported by BLHeli, you can modify the source code to handle any input you choose, and reflash the on board microcontroller. BlHeli is open source, so there may already be a branch that handles alternative inputs.

Important to note:

  • Don't drive the ESC to full throttle unloaded. Timing/field weakening can cause issues/de-sync that may cause damage
  • Don't do your testing with a propeller on, brushless motors spin quickly and can very rapidly cause damage to the degree of lost fingers.
  • If the motor is stuttering for a long period of time (more than a second), stop what you're doing an disconnect power. This will damage the ESC if left to continue.

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