how to remove electrical continuity of a circuit when not under power

Thread Starter


Joined Jul 8, 2016

I have a motor which I need to drive at 18V, the current draw is typically 0.25A, the motor produces a electromechanical break when the circuit is connected through the main control box even when not being run as the motor in theory shorts out, or that’s what I believe!

If I connect a wire from the positive to the negative of the motor without any power it produces the same break effect, so this is what I believe is happening through the controller,

I’m wondering if there is anything I can implement into the circuit which will remove the continuity of the circuit when its not live, possibly some sort of electrical switch in the loom which only connects the circuit when it detects a voltage supply?

The supply is from a control box which I don’t want to modify, if I run the motor with a bench PSU and a manual switch I can get it to perform correctly as I need it too and backdrive freely, but with the main control plugged into the motor it produces the break, and therefore wont backdrive when not being powered …

Any ideas?



Joined Jan 27, 2019
How about a relay between the controller and the motor?

This seems the most obvious route but I hesitate to suggest anythings specific without knowing the components becaus there could be something not yet known that would change things.

[EDIT: added an “n” to know so that it doesn’t seem like English is not my langue maternelle]
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