Maiden flight = almost instant ESC burnout

[hogster]

Hi all,

Some not so good news I'm afraid

I very carefully setup my X8 (w/ AQ) in my garden, made sure I had good GPS lock, and then gently spooled up.

Firstly all the motors spat into life at different intervals, and with enough speed to start to tip the X8 over. Then after a few attempts, one of the props stopped turning, and the ESC was emitting a constant *beep beep beep beep...* noise ... Thinking the ESC had just somehow lost sync with the motor, I power-cycled the system, and this time all 8 ESCs seemed to respond ok again.

Curiously, on putting my finger on the ESC heatsinks, they were all slightly warm to the touch, which seemed slightly odd as the motors had hardly spun for more than a few seconds.

On my next attempt to take-off, almost immediately smoke starting pouring out from one of the ESCs

My EagleTree logger showed that the current was peaking at 30-60A (!) during the initial spool up period, and up to 90A (!!!) during the second attempt where one of the ESCs burned out.

Is this a problem with the AQ PWM demands (was it trying to spin the motors up too quickly?) or are the ESCs just too cheap? The Cortex manufacturer hasn't had any other problems with these ESCs before ... I'm now worried that all 8 ESCs have been overstressed and I'm not sure if it's wise to use any of them again The starting PWM is 1125us – maybe this should be a lot lower? All 8 ESCs were calibrated by plugging them directly into a receiver and moving the throttle stick to full and back.

I've attached the EagleTree log file, and the AQ log files can be accessed here:

http://www.horizonimaging.co.uk/rcgroup ... les/4-5-14

I will upload a video file later where you can see these non-take-offs ... I'm not sure if it was just me, but the motors sounded quite rough, certainly on spool-up, as if the ESCs were really struggling to drive the props.

If case this was a combination of inadequate ESCs and too high PWM demands from the AQ, can anyone recommend easy-to-get-hold-of 30-40A opto-isolated ESCs that are good on 6S? Maybe ones which have a built-in soft-start and so can handle starting big props without burning out?!

Many thanks in advance for your support,

David

[chschmid]

[joebar.rc]

I dont think David did use esc32..
But if you where able to sue that defacto calibration it probably where not multirotor esc's anyway. Multirotor esc's (simon-k blheli, ultraesc and esc32 of course) dont use throttle calibration anymore.

Slow start is kinda a problem, all reflashed esc's did remove such features. Our esc32 can handle big props by using a start voltage to 'kick' the props and motors but as Christof mentioned only to 5S.

Maybe caste creations phoenix ice esc's with multirotor fw. Hopefully other will suggest some possible esc's for 6s

[hogster]

Hi guys,

Thanks for the replies.

I'm not using ESC32s, I'm using the unbranded ESCs that came with my X8, which have already given me once before ... I've no idea what make they are, but even CarbonCore, the manufacturer of the X8 said they were quite cheap Chinese ESCs which is why he supplies 9 with the X8!

This looks like quite a good alternative?

http://www.electricwingman.com/tiger-mo ... simonk-esc

25A (35A burst) should be sufficient for my X8 or not? From the sounds of it, the average draw for a setup like mine draws around 5A per motor (I'm aiming for around 5.5-6kg AUW):

http://shop.carboncore.co.uk/Videos

Many thanks

David

PS. Video just uploading now ...

[hogster]

Here's the video:


Password: hogstercortex

Thanks! David

[LPR]

David

I've use these ESC with good success on two quads with U8 T-Motors and 6s batteries. I'm thinking they will work for you.

http://www.foxtechfpv.com/dys-40a-opto- ... -1110.html

Larry

[hogster]

Hi Larry,

Thanks for the recommendation. Just did a quick Google and found this video:

https://www.youtube.com/watch?v=Q_0JpqDuy7k

Seems he had a FET problem with one of these ESCs - no big deal in itself, but what concerned me more was the other comments about the DYS 40A's on 6s ...

Hard to know whether these are isolated problems, or a hint towards a design issue – particularly as you've had no problems with them!

Thanks, David

[LPR]

David

The DYS ESC are low cost and you can expect not the best quality. Buy an extra one or two and in a few months the ESC32 V3 will be available.

Larry

[hogster]

Thanks Larry

What do most people use as their 'start PWM' value? The default is 1125us, but maybe this is too high and results in giving the motors too much of a jerk? I would have thought the ESC would just deal with that though ...

Many thanks for any other suggestions, David

[axelnied]