Tried a new torque sequence on a Dover gearless motor and it ran quieter

I was working on a Dover gearless unit in a Phoenix high-rise and decided to follow the bolt tightening pattern from an old service bulletin, not the usual cross pattern. The motor noise dropped by about 15 decibels after the adjustment, which was a surprise. Has anyone else had a specific sequence make a noticeable difference on a gearless drive?

2 comments

2 Comments

kelly_chen1mo ago

We had a similar thing happen on a Kone unit in a San Diego hospital last year. I mean, we used a star pattern from an old manual instead of the standard cross, and the vibration just went away. It's crazy how much the bolt order can change the whole alignment. I always check for those old bulletins now, idk why more people don't talk about it.

cole_mitchell81mo ago

Yeah, the bolt order thing is huge. I read an old forum post where a guy said switching to a star pattern on a similar unit cut noise by like half. Makes you wonder how many fixes are just buried in old papers.