Asked — Edited

Do You Use Protection?!

I've been looking at a lot of robot projects here and around the net lately and one thing really surprises me. I've yet to see anyone use servo savers on their robot. I'm sure there are people that are, but it seems really uncommon. I don't get why. We use servos in ways that put them under loads way beyond their design, like mounting an entire robot arm hanging off a servo. Or a robot head stuffed with cameras and sensors directly mounted to a servo or servo gear. This seems like a perfect place for a servo saver. Especially given the tendency for people to grab the robots and accidentally force servo driven parts to torque against the servo.

Can anyone shed any light on this for me? Thanks!

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They are probably used as often as people calculate the correct servo torque...

@Technopro, they are available in the EZ-Robot store.


@Technopro There are several types, but the basic function is the same. They allow the output hub to rotate independent of the servo shaft IF the force on the hub exceeds a set threshold. Usually that will be set at some point just below the rated torque of the servo. See here for an example on one type of servo Saver.

Servo Saver Example


There are lots of types of servo savers. They are like a clutch that releases under certain strain. There are also versions that use rubber bands. I guess there are situations to use them but I haven't. The only place I would use it is one moving sensors like radar in case it got caught on something. Like Rich is suggesting you probably won't need a servo saver if you had the right one for the job to begin with.


I have only seen the clutch type. And, they were only available for the micro servo to my knowledge. It would be nice to have them on all servos.


People that do a lot of R/C truck racing/jumping and stuff use servo savers to protect the steering servo's gears from getting stripped out. Imagine you're turning right on a high speed run and the truck slides, causing it to hit the curb (or pipe) pretty hard with the left front tire. This impact will momentarily try to turn your wheels, fighting against the servo. This can strip out the gears inside a servo. A servo saver is a plastic wheel with a fairly stiff spring inside. Any sudden hard jolts and the spring allows the wheels to move. It then snaps the wheels back to the proper position.


Servo Savers are widely used on RC car/truck and RC model airplanes. While I am a hardcore RC airplane guy, I too never realy use the servo savers but I know of fellow flyers who do. When needed, I tend to use slight overpowering servos for my needs anyways.