Sudden ESC issue

[SamCassidy]

Been working to get my 550 back in the air since christmas (Compass Atom 550). Got a new Scorpion HKIII-4020-1100kv installed and some new packs for it.

Did my first three test flights yesterday, First flight just ran it wide open with blades off to check and make sure everything was okay and smooth. @70% throttle for 3m 30s

Second flight (first actual flight) got the blades back on, was breaking in my second pack. Just hovered @75% throttle for 3m 30s.

Third flight still wanted to take it somewhat easy on the packs, Flipped into IU2 which was 95% flat throttle curve, WOW. Talk about a heli coming to life, it was like it got a direct IV of meth. Almost a little too much.
ESC still came down very cool (less than 80 degrees id say) the motor was a little warm but not much even for scorpion standards.

About halfway through my third flight I did a single forward flip (just for the heck of it) then flipped into IU1 from IU2. As soon as I did I started to loose all power (I assumed that I over-amped / shut my ESC down, managed to do a half decent but pretty crappy emergency auto after trying to re-start my ESC in air on the way down. Turns out my pinion just slipped on the shaft.


TODAY, went out and flew two packs, all went well except for some minor vibe issues on run up and run down from my blades being out of balance. (potential bent feathering shaft, from yesterday can't get them to track).

Then third pack my ESC shut down, for no reason, no fire, smoke, etc. This is a Castle Talon 90 I have been running since the release with no issues whatsoever.

Figured it might just be an anomaly, came in and did some tinkering and worked on a few potential problem areas I noticed, charged up two packs and went back out.

Instant shutdown 30s into flight, every single time. Took it inside and took the blades off, spooled it up and ran it wide open for 2 minutes and could not get it to shut down again.

Only thing I have changed is my gyro gain down by 5% (tail was unhappy yesterday).

Even tried putting 500 blades on and running at only a 70% flat curve, same thing, instant shutdown.

Any ideas? Im pretty pissed.

Compass Atom 550 - Scorpion 4020-1100kv - Castle Talon 90 - Align DS510m's (cyclic) - DS520 (tail)

[RedOctobyr]

What's your LVC set to, for threshold, and behavior? Simplest test would be to temporarily disable LVC, and see if it goes away. Then turn it back on, and figure out the real cause, of course

Without logging, things get trickier. Is it correctly identifying the cell count, for LVC purposes? Do you have a bad connection somewhere that's causing added resistance, and triggering LVC?

I'm assuming it's not a current-limit type of problem. What's that limit set to? Any binding in the drivetrain?

[SamCassidy]

Originally Posted by RedOctobyr

What's your LVC set to, for threshold, and behavior? Simplest test would be to temporarily disable LVC, and see if it goes away. Then turn it back on, and figure out the real cause, of course

Without logging, things get trickier. Is it correctly identifying the cell count, for LVC purposes? Do you have a bad connection somewhere that's causing added resistance, and triggering LVC?

I'm assuming it's not a current-limit type of problem. What's that limit set to? Any binding in the drivetrain?

1) Threshold for LVC is 4.15 I believe. Only ever hit LVC once that was flying an already depleted pack for an extra 2 minutes. Id check but can't find my damn castle link at the moment

It is a soft-cut-off that sounds / acts like hitting LVC however but I don't think it is, otherwise I would have had issues before I swapped motors, correct? Not sure why changing motors would affect / cause it to hit LVC. This is right when I take off, not even 30s into the flight.

2) It is correctly identifying cell count

3) Don't believe I have any bad connections as I re-did all my solder joints when changing motors (esc leads going to esc have to mount on wires that have bullet connectors on the other side for the scorpion motor leads). The ESC wire going to VBAR is in braided wire wrap / shrink wrapped so I don't thinkk it could have gotten damaged in any way. Plug going into vbar is fine.

4) not sure on the current limit? It should be at the default setting for the Talon 90.

5) No binding in drivetrain

[SamCassidy]

Like I said, never had any trouble out of this ESC up until today. First four flights on the new motor after the swap were fine.

[SamCassidy]

This couldn't be PWM / timing related, could it? Or even endpoint travel?

I set the pwm, timing, and endpoint travel when I first got the esc and was using it in the 550 with the stock compass 5016-1100kv.

On the first 4 flights everything came down cool and the motor had plenty of power, assumed the PWM and timing were fine and my endpoints would still be correct...

[SamCassidy]

.....why I post things in the main forum.. lol

[Xrayted]

Originally Posted by SamCassidy

This couldn't be PWM / timing related, could it? Or even endpoint travel?

I set the pwm, timing, and endpoint travel when I first got the esc and was using it in the 550 with the stock compass 5016-1100kv.

On the first 4 flights everything came down cool and the motor had plenty of power, assumed the PWM and timing were fine and my endpoints would still be correct...

Set the amp cuttoff to "Insensitive" if you haven't already. Also consider a slipping one way bearing. They will cause these ESC shutdown symptoms when everything looks perfectly normal otherwise. The bearing will slip then grab, causing enough of a sudden spike to shut down

[SamCassidy]

Thank ya! I will check into that and report back with any progress. Between this and my other thread ( https://www.helifreak.com/showthread.php?t=595171 ) I'm pretty stuck right now, have a lot of work to do on it
Thanks again!

[Xrayted]

Originally Posted by SamCassidy

Thank ya! I will check into that and report back with any progress. Between this and my other thread ( https://www.helifreak.com/showthread.php?t=595171 ) I'm pretty stuck right now, have a lot of work to do on it
Thanks again!

Here are a couple post having similar issues that might help you out. Its tricky because the ESC always gets targeted, yet the real culprit may actually be completely unrelated to it..

https://www.helifreak.com/showthread.php?t=546577

http://www.rchelination.com/forum/mo...ng-punch-outs/

[SamCassidy]

thank you all for the replies. Took a bit of a break, going to dig back into it soon.

[CharlieK]

An LVC of 4.15v per cell is too high! It should be about 3.2-3.3 for Lipos.
Even then, if the lipo is too heavily loaded for it's actual capability,
LVC may trip.