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How to brake DC motors and servos

Hello everyone,

I want to brake continuous rotation servos by shorting the leads using the back emf. But I'm wondering how to do this safely without shorting the supply. I could use a switching transistor to switch off the supply before shorting the leads, with another switching transistor? But this seems risky, I'll have to take a voltage hit to the servos from the PN junction drop and then if something goes haywire in the control or transistor then the batteries and possibly other things go up in smoke. Suggestions? Thanks.

-Dave

Reply to
Dave
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If these servos still have their own control guts (you haven't replaced it with an H-bridge of your own) then the motor inside the servo is not directly connected to the V+ and ground leads. It's doubtful shorting out the leads of such a servo would do anything but eventually wreck the servo.

If you are using an H-bridge, some of them support braking as long as the current limits are observed. If you are building a bridge, you might want to Google for the term "dc motor dynamic braking" (no quotes) to look at designs.

-- Gordon Author: Constructing Robot Bases (Forthcoming) Robot Builder's Sourcebook, Robot Builder's Bonanza

Dave wrote:

Reply to
Gordon McComb

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