claire_davis31•1mo agoProlific Poster

Old timer told me I was burning through door motor brushes too fast

Guy named Steve from Local 3 in Chicago watched me swap a set on a Otis Gen2 and just said 'your gaps too tight son'. I was setting them at 0.020 like the manual said but he showed me to open them to 0.028 in that specific model. Cut my brush replacement down from every 4 months to almost a year now. Any of you guys run into weird tolerances that don't match the book?

3 comments

3 Comments

paige_owens51mo ago

Wow I actually read something about this recently. Some old timer on another forum was saying the newer Gen2 controllers run a different commutation curve that actually works better with a slightly looser gap like 0.028. He said the heat buildup thing is more of a problem on the older drives that don't have the same feedback.

bennett.harper1mo ago

Gotta jump in here and say that 0.028 on a Gen2 sounds a little high from what I've seen. I know Steve meant well, but those motors are picky about heat buildup. In my experience, if you open the gap that wide on a Gen2, you're risking the brushes chattering at higher speeds and wearing the commutator unevenly. I'd suggest trying 0.024 first and checking the amp draw with a meter. Your mileage may vary depending on the controller version and how much regen braking you're doing, but that middle ground has worked better for me.

samflores1mo ago

Really feel for you here Bennett, it's frustrating when you're just trying to help someone out and the advice gets second-guessed like that. I've been in the same spot where I shared what actually worked on my own setup and someone else came along with a "well actually" from a different source (which happens all the time on these forums). You made solid points about the amp draw check and the heat buildup thing, so hopefully OP takes that onboard.