Originally Posted by
John Wallace2
Re ran my R1 21.5 on my Motorlyser at real 43* timing I got a 3.5 degree variation reading. However, that appears to be the average variation of each sensor from the average (3.5) because two poles were at ~40 degrees and one was at almost 48. Asymmetry reading was 15 (not good)
Your sensor assembly probably looks just like Torg's I posted. Let's say the lower yellow sensor is #1, clockwise to #2, then further to #3.
Making up numbers for the explanation...
Distance between #1 -> #2 = 10mm
Distance between #2 -> #3 = 8mm
Distance between #3 -> #1 = 12mm
With the endbell set so #1 is ~40*, #2 would be ~40*, but the distance between #2 and #3 is shorter - resulting in sensor #3 being far more advanced than #1 & #2. The secondary problem is the ESC having to wait longer for #1 to return due to the longer distance between #3 -> #1. At high timing settings, this is where the cog develops.
I'll see if I still have any of the bent/twisted/non-level ones left in my motor box and post some pics.
The super-junk rotor from my 1st 13.5 was waaaaay out there. First test on an i-Gauss made me change the battery thinking it might not be reading correctly. Second test on a different i-Gauss was similar, 3rd test on a RMS fell right in line with the i-Gauss readings. I think the Motolyser showed asymmetry in the 60's. That rotor now lives in the ceiling rafters at MRH.
Also, to clarify, the one sensor assy I found with <4* variation was the actual numbers, not the Motolyser's variation reading. I also observed the variation to actual advance discrepancy on the Motolyser and no longer rely on that reading. It's good for a quick glance/ballpark reading but the individual advance read from each pole is a little more accurate.