@@ -14,7 +14,18 @@ The image below links to a video of the target mounted with under 10um of perpin
And [here's another video showing the first step of sweeping the turned delrin encoder mount](https://gitlab.cba.mit.edu/davepreiss/ldcoder/-/blob/master/images/rotorNoTarget%20.mp4) that's sitting underneath the rotor. It took some adjusting with a flathead screwdriver to dial it into under 10um error, but seems stable and should be fine for initial testing despite just being a press fit at the moment.
Before mounting and testing the encoder
Before mounting and testing the encoder I wanted to test some parameters of the new coils (inductance, quality factor, and ESR) which are important for properly configuring the encoder. I was able to borrow an impedance analyzer from Signal Kinetics for the day and was able to do these measurements, although strangely was seeing an order of magnitude change in inductance when measuring at 10kHz and 200kHz. To sanity check this I measured an OTS wire wound surface mount inductance rated at 10uH which measured spot on at 10.028uH and 10kHz and 10.071uH at 200kHz, so something is definitely amiss and I still haven't quite figured it out.
It's worth noting that inductance numbers were definitely asymptoting off around 200kHz (at 150kHz we had dropped to only 1.133 from 1.044
Two explanations I thought of could be:
Because the coils are unshielded (unlike the SM component) at high frequencies we are casting flux further and therefore being more effected by pieces of metal on the order of 10's of mms away
Because the top and bottom coils are only 0.8mm apart and highly parallel, at higher frequencies we are getting more of an effective parallel plate capacitor effect
