I have a linear actuator that I'm using two relays (Wired as a h-bridge) to control the movement of my actuator. Is it ok to leave power to it all the time, or do I need to cut the power once it reaches its travel limit?

Thanks! -Brennan

  • $\begingroup$ Motors often behave differently when stalled, which is what would be happening if you drive it to the end of its range of motion and continue to put power into it. Whether it will harm it depends on the type of motor and possibly on the driver electronics. If the actuator does not back-drive (some ball screws can), turning off power is recommended. $\endgroup$
    – Pete W
    Apr 20, 2021 at 19:16

1 Answer 1


Using two relays combined with limit switches implies that the movement is caused by one relay engaging until the switch is tripped, while the control commanding the movement is also engaged. When the switch is triggered, power to that relay should be removed and power use should cease.

When moving in the other direction, the control engages power to the previously unpowered relay, allowing movement until the limit switch is once again triggered.

During this period of movement, both relays are capable of being powered, but the movement control should be designed to prevent simultaneous actuation.

If your system is not designed in this manner, I'd be surprised, but if it is not, consider to post the electrical diagram in use.


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