Soldering caps to micrometal gearmotor housing?

For best noise reduction it is recommended to solder small capacitors between each motor lead and the metal motor housing, as well as directly across the leads. I have the 30:1 micro metal gearmotor, and I’m concerned about the plastic endpiece that holds or forms the rear bearing as well as the terminal spacer. Does anyone have experience with the resistance of this plastic part to soldering temperatures?

I’ve successfully soldered caps to motors with metal endpieces and have noticed that it takes a lot of heat for the solder to stick well. I don’t like the idea of disassembling the motor prior to soldering because of the possibility of damaging the brushes.

On the other hand, is motor noise a serious issue with the 30:1 motors? Possibly one cap would suffice.

Thanks, Jim

Hi, Jim.

I’d be concerned about being able to solder to the housing, too. I think just one cap, across the terminals, is fine. On the 3pi, we have a single cap on the PCB (so it’s farther from the motor than if you had it right on the leads), and we run the motor at a fairly high voltage, and we haven’t had any problems. The HP motors are probably noisier, but I still wouldn’t bother with the other two caps.

- Jan