PowerPro Belt Alignment

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PowerPro Belt Alignment

Post by DLB »

My PowerPro (PP) was running fine but I was aware that the lower belt (motor belt) was not running true. I had installed the system according to the DIY video instructions. For background, I want to refer to this other thread: viewtopic.php?f=10&t=24090 but it is long so I want to paraphrase a couple of important points:
1) The DIY video instructions for adjusting the Belt Alignment screws on the PP motor are completely different than those in the manual.
2) The OP reports in a conversation with the primary SS maintenance person that she does not use the method in the manual.

I had tried the method in the manual, and only succeeded in making an annoyance into an actual problem. In that method, you are essentially tilting the motor so that a straightedge held flat on the pulley will line up with the correct intercept point on the Idler. In doing that on mine, it took the axis of rotation of the motor way out of alignment with the axis of the Idler and Drive Sleeve. I ended up with two wrongs not making a right. There were two primary contributors to the actual problem: one was that the motor pulley was not installed against the snap ring (by about 1/16" in my estimation) and the other was the motor off in the motor mounts by about three or four times that much. These two errors were additive, placing the pulley off to the right of where it should have been by roughly 1/4". The Belt Alignment procedure will not correct this though it may appear to, it misaligns the axis of rotation of the motor rather than aligning the pulleys.

To correct this condition, I first moved the motor pulley to be in contact with the snap ring (this is discussed in the other thread and is correct per SS). I added blue loc-tite to the setscrew, also discussed in the other thread. (Note- this is a 2020 DIY kit and there was no evidence of factory loc-tite. SS has been recommending loc-tite to customers for years, and I was expecting to see it as part of the factory installation of the pulley. So I also pulled the fan and added loc-tite there as well.) I moved the motor as far to the left as it would go in the motor mounts by loosening the setscrews that secure the motor in the dove tailed mounts. At this point I was close, but not happy that I had the pulley as far to the left as I could move it and the alignment showed it still slightly to the right of where it should have been.

Measurement method: In the DP configuration, I used a Wixey angle gauge and 3-3/4" lathe faceplate to first confirm that the axes of rotation of the Idler and Drive Sleeve were the same. Then I put the Wixey on the motor pulley and adjusted the Belt Alignment screws to match the motor axis of rotation to the others. I then used the straightedge held on the pulley to see where it intercepted the Idler. If it had been possible, I would have moved the motor until its pulley aligned with the correct intercept. Unfortunately, I ran out of adjustment without reaching that point. (Neither DP nor Wixey, nor faceplate is required, just what I used)

Conclusion - In my opinion, the Belt Alignment procedure in the manual can only solve 'the problem' if it is the exact right problem. If it is not the right problem, it is going to make it much worse. The only correct answer is that the axes of rotation need to all be parallel, within a small tolerance, and the pulleys need to be in alignment so the belts run true. I would only use the Belt Alignment screws to change the motor axis of rotation if it was provably wrong, measured in relation to the axis of rotation of the Idler.

- David
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