Report on Hobbyking 40A ESC 4A UBEC 9261000003 / BC3540-14 brushless drive

This article documents some a test on elements of a drive system which is the basis for one of my flying quads.

Test configuration:

  • Gemfan 11×4.7″ SF propeller;
  • BC3530-14 1000Kv motor;
  • Hobbyking 40A ESC 4A UBEC 9261000003 (BEMF caps removed);
  • SimonK commit 02bd8e4ca36a06722efe51bc7cd5130d72a184b8 bs.hex with 2000ns dead time; and
  • 4Ah 4S Lipo battery.

The dead time was chosen for compatibility with F-40A which I also use. Dead time of 1200ns is sufficient for the 9261000003.

This is quite a low cost drive, the 300W+ motor cost about A$14 and the 40/60A 6S ESC just under A$20 at the time of purchase.

The tests were conducted at 4S as a stress test (up to 170% of rated current), the quadcopter uses 3S.

The tests were ‘scripted’ by an Arduino RC servo ramp generator.



Above is a graph of current and rotational speed from Elogger.

The drive system is very responsive and shows not signs of sync problems (evidenced by erratic current for instance).

The ESC comes with 4700pF BEMF capacitors which had to be removed for best performance.