"miss-commutation" ???

Quote:

The lower the timing the more power You get from the motor (this is why the manufactorers show all power data at the lowest possible timing) but the hotter it will run due to the currents get higher. So does the ESC temperature. Also the probability of a 'miss-comutation' raises massiv -> motor / ESC quits in high load situations.

Does a "miss-commutation" produce a squealing sound from the heli motor? I had my timing set to auto on my 690sx/YGE160 and either my pinion set screw sheared and then happened to catch again or this timing error occurred. While in a turn, my heli started to squeal and I lost all motor power. I went into a very distant auto and about 10 feet from the ground the squealing stopped and I had power again, so I flew back to my landing area.

I couldn't get the pinion set screw out and had to press the pinion off the shaft and drill a new set screw hole....so I couldn't tell if it sheared in flight and then jammed again or not. I've had a pinion set screw shear on my 550 and it sounded similar, but in that case, the power never came back and I finished the auto....after which the pinion spun freely on the motor shaft.

For now, I have set the timing to 18 degrees instead of auto. Any info on the characteristics of a miss-commutation would be appreciated.

Thanks,
KevinB



Edited 1 time(s). Last edit at 09/03/2014 02:44AM by KevinB.

Hi,

a squealing sound together with a loss of power can be evidence for a commutation error. Auto timing, especially with large motors, is difficult.
With a default fixed timing setting, you should have no issues.

Kind regards

Eddi

Born to fly ...
forced to work.

Thanks! I'll leave it as is then on the 690sx with fixed timing.

On my 550sx and 550se, I've always used auto timing ( the last 2 years ) and never had a problem. Have I just been lucky?? Or is the smaller 4025 not vulnerable to the miss-commutation problem like the 45 class motor? If there is a chance it could happen on those as well, I'll set those to a fixed 18 degrees as well.

Thanks for the info Eddi !

Kevin

Hi Kevin,

the smaller motors are not that demanding, but it also depends on the winding, the magnets and a few parameters more.

I have been flying auto timing on my Kontronik ESCs, years ago, on all kinds of helis. Interestingly, if I recall, the bigger machines all had Kontronik inrunners at that time, and the smaller ones hat e.g. Z-Power or Hyperion outrunners. So the comparison is lacking a little. But my style of flying would probably even bore my grandma if she was still living ...

After that, I have been using fixed timing on chinese crackers as well as on YGE ESCs or Castle ESCs.

For example, the YGE 90 when set to VBar Governor Mode, is also using a fixed timing. That is also what YGE recommends. So to be safe, I would switch, and maybe compare back to back what difference it makes power wise, temperature wise and regarding used capacity over time.

Kind regards

Eddi

Born to fly ...
forced to work.

Thanks Eddi.

I did do back to back comparisons with my 690sx using auto and 18 degree timing. The auto timing definitely brings a little more power to the table......but if there is a chance of another complete loss of power, the extra isn't significant enough to take the risk of it happening again where I perhaps don't have a chance to auto.

This first time with the 690, I was over a large bluff of trees when it happened and JUST managed to clear the edge of them before I ran out of altitude.

I'll set everything to a fixed 18 degrees and count my blessings .

Thanks!

KevinB