YGE 90 LV over current cut off (with video)

[HeliAxe]

Well I have been flying my Goblin 420 with the Turnigy Nano Tech 2650mA 45-90C batteries for some 60 flights no problem. Motor is the KDE500XF-925-G3.

I also recently purchased some SAB 2500mA 50C batteries to give them a try and I could tell straight away that the SAB batteries had way more punch. Now that the SAB batteries are finally run in nicely I thought I'd push it a bit today (a hot 90 degrees Fahrenheit) and 15 seconds into the flight I lost all power to the motor. The BEC output was fine as I was still able to control cyclic and managed a bumpy auto with thankfully no damage what so ever to the heli.

I disconnected the battery, conducted a close visual inspection which was all good, reconnected the battery and continued with a softer flight no problem.

I suppose I am on the limits with a powerful motor and batteries that can actually deliver on a power spike maneuver

Has anyone seen this before?

YGE90LV Current Overload ? (0 min 35 sec)

[HeliAxe]

The more I look into this the more I am thinking its a commutation error

[KevinB]

the more I am thinking its a commutation error

Given the sound, that would be my guess. You aren't running the YGE with Auto Timing enabled by any chance ???

The same thing happened to me twice on my 690sx. After I switched the timing to a fixed 18 degrees instead of using the Auto timing feature, I haven't had the problem since.

KevinB

[HeliAxe]

Good point. I actually thought the sane thing and checked. My timing is set fixed to 6 degrees.

Given the noise it made after it lost power, I don't think it was a current overload issue. Weird ???

[KevinB]

One other thing I've been told regarding YGE ESCs......their timing numbers don't correspond to other brands.

For low/medium/high timing settings on a YGE, you should be using;

-for an in-runner motor, the 0/6/12 timing settings should be used for low/med/high timing settings

-for an out-runner motor (like the KDE and XNova motors....where the motor can spins and the armature is stationary), the 18/24/30 timing settings should be used for low/med/high timing settings


So, you may want to try 18 degrees and see how that works for you. I've been running my KDE600XF-1100-G3 motor at 18 degrees timing on a YGE120HV ESC for well over a year now and it's been flawless.

I know the KDE timing recommendation for your motor and mine is 5-15 degrees. However, check out the timing recommendations from XNova's website: (http://www.xnovamotors.com/xnova-motors-esc-settings)

Timing:

Normal or low timing is ok for the Xnova motor on Castle Creation. You can experiment with your setup to see which mode produces the most efficient operation.

Additionally setup samples for Castle-Creation:

Xnova 40** series: 3 or even lower for timing and 12KHZ.

Xnova 4530-500KV-8D or 450KV-8D : 3 or 5 for timing and 12KHZ.



YGE:

18* for timing ,PWM Start with 8.

P and I gain = default.

..........so there is obviously a difference in how YGE measures their timing.


That's about all the ideas I have on this one.

KevinB

[HeliAxe]

Wow, fantastic information Kevin thanks for sharing Makes sense.

I usually run auto timing or at a fixed value around 6 degrees and this is the first time I personally have had an issue. I will definitely change my timing on all my YGEs including G570 (YGE 120HV) and Urukay (YGE 160HV) from auto to 18 degrees, just to be on the safe side.

Although not directly related to RC Heli's, this is still a good read on commutation of brushless motors and ESCs.

http://blog.aerotechmotioncontrol.co...linear-motors/

[KevinB]

You are welcome!

I always used auto timing myself on my first larger electrics. (a Logo550sx and 550se) Never had an issue there.
I flew my Logo690sx for almost a year before it happened the first time right near the end of the flying season. That summer I had been getting more aggressive in my flying style and in my collective setups and that may have contributed to it. The heli was out quite a ways and there were nitro planes flying so I never heard "the sound". All of a sudden the heli rolled on its back and I could see the blades slowing. This was at near tree-top height so there wasn't time/room for a auto. I rebuilt over the winter. The next spring it happened again but I was able to auto safely. This time I heard the sound and then learned about the bad commutation phenomenon and changed all my larger helis with YGE ESCs to fixed timing. (all to 18 degrees)

I haven't had it happen since.

Happy Flying! I'm still waiting for spring here. It's currently -20C outside.

KevinB