Motor stops while flying

[nielsoe]

Hi

Im pretty new to Multiwii and have manged to build a Quad set in X-config. The thing has flown once, with reasonable control, so I guess the overall setup is OK.

My problem is that suddently one motor stops while in flight mode (not idle). This offcourse results in a crash.
I have tried to investigate the problem by holding the quad by hand. When idling there is no problem, but when throtteling up, one motor ususally stops within around 10-40 seconds. Not always the same motor.

I saw some that the shaft of the motors were a bit blurry when running high speed, and thougt it was due to vibrations in the frame, as it was build by aluminium T-bars.
I have build a new frame i rectangular bars, and it is much more stable. The motors keeps stopping thoug..

After reading on this forum, I now susspect the ESC/motor combination.
As I build on a budget, I might have bougt to cheap components from DealExtreme.
Maybe they do not match very well. The motor was chosen after reading on a site (?) that one should go for low KV for a quad.

The ESCs are 4x FLYING 30A (http://www.dealextreme.com/p/flying-30a-bec-electronic-speed-controller-for-brushless-motors-esc-11981)
and the motors are Mystery A2212-15 930KV Outrunner Brushless Motor (http://www.dealextreme.com/p/mystery-a2212-15-930kv-outrunner-brushless-motor-35706).
The propellers are 10x4.5"

I am not sure how to calibrate and program the ESCs, as there no documentation.

I am not sure what to do next. I hope to get it in stable flying condition with the current setup, as I hate to buy new motors/ESCs right now.
I browsed the long thread on flashing ESC, but it seems too overwhelming to read, and I am not shure it will help.

Any suggestions will be appreciated!

[PatrikE]

Try to increse minthrottle to avoid inair stops.

Code: Select all

#define MINTHROTTLE 1150 

[mr.rc-cam]

I am not sure how to calibrate and program the ESCs, as there no documentation.

The throttle range needs to be calibrated in order for the ESC to work in harmony with the MINTHROTTLE setting. You also need to ensure the ESC is programmed correctly or the ESC's low voltage cutoff (LVC) feature may incorrectly shut off the motor. I used Google and found the instructions.
http://club.dealextreme.com/forums/Foru ... did.338371

[mgros]

I had the same problem and the only solution was change motors and/or regulators.

If the problem affect only to one motor could be a solder problem, but if it affect to all randomly, it seems an electronic compatibility problem.

Try to reflash the ESC.

[mr.rc-cam]

My problem is that suddently one motor stops while in flight mode (not idle). This offcourse results in a crash.
I have tried to investigate the problem by holding the quad by hand. When idling there is no problem, but when throtteling up, one motor ususally stops within around 10-40 seconds. Not always the same motor.

Shortly after you posted this problem I had it too. The motor that stopped would be random. It caused a few inflight crashes while I was sorting it out.

It was *very* intermittent and would never occur during bench tests. While flying, motors would randomly stop (which causes a dramatic flip/crash). Sometimes they would not start up when they were first armed (or would cog more than usually before they started). I was planning to replace all the motors and ESC's. But fortunately I found the cause before wasting my time with that shotgun solution.

It was the BULLET CONNECTORS on the motors. Doubtful, you say? Well, on my bullets the Male side of the connector pair are actually composed of two pieces, a machined center hub and stamped expanding tip (the flower part). The two pieces simple fit together with a mechanical crimp. This results in an unreliable electrical connection especially considering the high motor currents we use. The problem cannot be seen by visual inspection so it is a very difficult thing to diagnose.

Since new bullets would probably have the same issue after a few flights, I repaired ALL the existing bullets by carefully soldering the mechanical crimp. All the weird symptoms went away instantly after doing that. If I was smart I would have just removed the bullets and eliminated them, but I like the convenience of unplugging motors for quick repairs.

Long story short, trust nothing and test everything. It is all suspect.


- Thomas

[UndCon]

I said it before and will say it again - never use bullet connectors.

I had my share of crashes due to bad connectors and always solder wires since then.

//UndCon

[mr.rc-cam]

I said it before and will say it again - never use bullet connectors.

Wise words indeed.

- Thomas

[jevermeister]

I have this kind of problem with the following combination:
Hobbyking SS 18/20 (not programmable) and EMAX CF2822 (either with 8" and 10" Props)

Sometimes the motors stop without the ESC beeping, I can recreate the problem by holding the copter in hand and tilt or pitch it fast by force, the motor that has to throttle up to compensate the movement simply stops, I need to disarm and rearm to get it working again. Any ideas?

This is very strange, I planned to switch to Hobbywing Flyfun 18A quite some weeks but it is a lot of work though :-/ They are programmable so it would better to use them, wouldn't it?

Nils

[mgros]

Nils, you should read this
http://www.multiwii.com/faq#One_motor_stops_suddenly_in_a_flight
It seems you should change ESC.
Or try the new Output mod at less frec. as you can see in this post.
http://www.multiwii.com/forum/viewtopic.php?f=8&t=1427&start=10

Have luck.

[UndCon]

Sounds like a timing issue

http://www.undcon.com/2011/04/01/turnig ... ogramming/

[jevermeister]

Okay,
I switched the ESC to programmable 18A form Flyfun.

Okay the motors sound WAY differeent now, they give these humming noises while flying. Is this connected to the higher timing?
The Minthrottle had to be adjusted to 1300 in Multiwii Code or you get bad wobble of death pretty easy.

All Parameters needed to be revisited (had not done that yet due to bad weather in Kiel).

Everything seems smoother now.

Nils