I took a bit of the morning to run the flux leakage tests. The first pix shows the Turnigy C80100-130 in it's high tech wooden test fixture.
The wires come out what I call the fixed bell. Station zero is the end of the outrunner closest to the fixed bell. The stations move towards the "prop end" in 0.25 inch increments.
For the first graph I aligned the center line (C/L) of one magnet with a pole. I measured down the center line of the magnet on the exterior outrunner shell. I then measured down the line marked 10 degress CCW looking into the motor from the prop end, 20 degress CCW, and finally 25 degrees Counter ClockWise.
For the second graph I turned the fixed bell 10 degrees CCW, and repeated the three measurements above.
For the third graph I turned the fixed bell 20 degrees CCW, and repeated the three measurements above.
My Preliminary Conclusions... don't you love engineers that work in "high risk" areas? Everything is "preliminary", until the project is successful.
From the first graph you can see that things are funky near the fixed bell. You have to get at least to station 5, or 1 inch from the fixed bell to get a decent signal. (Yes, Excel added a 1 to my station numbers. Excel station number 1 = Turnigy Picture station 0. You also need to stay clear of the prop end, but not by so much, s minimum of two stations or 1/2 inch.
If it were me, I would put the hall sensors over station 7, or 1.5 inches from the fixed bell towards the prop end. That looks to me like the preliminary
optimum at this time.
I could just sneak my probe into the assembled motor to measure the surface flux on the magnets when they were between pole pieces, I measured right around 4900 Gauss. I could almost jam the probe into the air gap between the magnets and the pole piece, but I couldn't justify the cost if I ruined the probe, so I didn't do it!
I'll cut the plots a bit different and post them in a while.