On Friday, January 31, 2020 at 7:27:53 PM UTC-5, Eric Greenwell wrote:
Dave Nadler wrote on 1/31/2020 12:15 PM:
On Tuesday, January 28, 2020 at 9:59:56 AM UTC-5, wrote:
How hard could it be?

Here's an update from another skilled practitioner:
http://www.streifly.de/news-e.htm

Any idea what the "electromagnetic disturbances" are disturbing?

Some controllers use Hall sensors for position sensing and phase control.
Others sense back EMF generated by the motor to do the controlling. If those signals aren't "clean", not so good stuff happens.
That is the "simple" explanation.
UH