I am using a 24V DC motor in my application.

I would like to stop my 24DC motor rotation in one direction only i. e. suppose the DC motor is rotating clockwise, in my application, it may happen that it is being rotated anti-clockwise by the user forcefully. Now, I would like to stop that from happening.

I am thinking of using some kind of electronic lock which will latch itself upon receiving an input but not sure about it.

The thing is, it is not supposed to rotate unidirectionally. It rotates in both directions. And when someone tries to rotate it in the direction it is not supposed to rotate forcefully, my sensors detect it and the controller is then supposed to send the command to the lock then.

Any suggestions(I need something which will lock itself upon sensing something like this happening, not at all times)!

Thanks in advance for your help.

  • 1
    \$\begingroup\$ Do you have an electronic velocity/position control loop already? If yes, use that one. Otherwise, consider an electromagnetic brake that is released only when the motor is running. If it is enough to provide some resistance rather than a full lock, it might be enough to use a diode to short the motor winding when going in reverse. A mechanical ratchet might be simplest. \$\endgroup\$
    – polwel
    Feb 6, 2022 at 17:07
  • \$\begingroup\$ How forcefully? Because if the motor is only ever going to be driven uni-directionally, then a flyback diode in parallel with the motor would short it when it tries to motor in the opposite direction causing it to act as a generator. But this force would be speed dependent and ineffective at low speeds. It would just resist the user but not stop them. \$\endgroup\$
    – DKNguyen
    Feb 6, 2022 at 18:17
  • \$\begingroup\$ Can you use a worm gear? Such as machinemfg.com/why-is-the-worm-gear-called-the-worm-gear \$\endgroup\$
    – Ralph
    Feb 6, 2022 at 19:09
  • \$\begingroup\$ use something like a spring clutch \$\endgroup\$
    – jsotola
    Feb 6, 2022 at 19:13
  • \$\begingroup\$ @DKNguyen it isn't. It rotates in both ways. I have edited the question to add more clarity. \$\endgroup\$ Feb 7, 2022 at 3:55

1 Answer 1


If the electronics can sense operating conditions and control the motor at the same time then options are an electric friction brake; or solenoid locking mechanism (solenoid); or maybe switching in a generator braking resistor but that would not necessarily lock the position only increase the torque necessary to turn the shaft. If there is a large gearbox it may be difficult or impossible for a user to turn the output shaft and less braking resistance would be necessary to lock the shaft.


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