Inspired by drewjets video, I tried fitting sensors inside the astro too.
It turned out to be a pretty fiddly job to get the timing right
, but it works well on the bench now
I had a couple of attempts at fixing halls to a circular piece of strip board that was machined to fit inside the end cap.
The second attempt worked better.
I needed to get the sensors further away from the stator fields.
Hall positioning was complicated by having to avoid a large lump of snot stuck to the end of the rotor, -presumably for balancing.
To sum up:
wye current was 0.6 A, delta current was 4 A (was 0.6A and 3.5A with external hall setup and also with sensorless controller), so efficiency looks pretty similar so far. With This method it took about 1 hour to make the parts and the rest of the day trying to get the timing right! -sort of the opposite way round to the external method.
I can fit both internal and external sensors to the same motor, so should be easy to do a proper comparison of performance when it is fitted to a bike.Edit update:
This internal fitment does not work well in practise, it is upset by the magnetic field from the stator
See more info later in the thread here viewtopic.php?f=30&t=14210&start=180#p545457