Motors Jittering at ~10rpm After Arming, no throttle control

soler

Member
Hi All,

I have just received a new frame (tarrot 680) and decided to move all my Flame wheel 550 DJI equipment over (motors / DJI ESC / Naza) over to the new mutlicopter. I had everything assembled and double checked and powered up the system.

The Naza went though the normal beeps, I then armed the motors and all the motors jutter round at about 10 rpm. By jutter I mean that they turn 30 degree', pause for 1/4 second turn 30 degrees etc. Raising the throttle has no effect. I tried connecting to PC to see if there are any error messages and there are non.

I have checked the wiring so many times that I gave up and moved everything back to the Flamewheel 550 to double check. Now I have the same problem on the frame wheel using the all the original equipment.

Swapping round motor / ECS's does not seam to have any effect.

Any ideas what to try next?


Thanks
 

soler

Member
Short Update.

I have tested the Naza and the Receiver, these all seam to be good.

I also tied to drive one ESC and Motor from the receiver, eliminating the Naza and I got the same jumping results so I conclude the Naza is Ok.

Next I used a power drill to drive each of the motors and check the voltages between each of the cables, they all measure then same apart from one motor where one lead measured 50% of the voltages of the others. Although this is not correct I do not suspect that this is enough to cause all motors to jump as they were doing before.

This only leaves the ESC's. Any good suggestion on how to test these?
 

OneStopRC

Dirty Little Hucker
Don't you think it is weird, that all 6 ESC's would have gone bad at the same time?

Just a though, maybe your Receiver is bad? What is the radio setup and have you checked your battery voltage? For the Naza to be giving you the correct start-up beeps, tells me the ESCs are responding ok. Hook up to the assistant, check your commands from your radio gear and see if your getting any input.

Some radios have a bind plug, possible you removed this? maybe dropped the bind with the radio?

Give us more information on your setup, we are kinda running blind here.
 
Last edited by a moderator:

soler

Member
Hi, thank you for the reply.

For the radio I have a Futaba 8FG Super and the Futaba R6208SB receiver, connected to the Naza using S-Bus. This seams to be functioning well as I can see in the assistant software that all the sliders are moving normally. No other errors in the assistant software.

I can see that there are commands going out from the Naza as I can try to arm the motors, when this happens each motor jerks 1/4 of a turn and keeps jerking round until I disarm the motors.

At the moment I have tow possible reasons for the failure.
1. The new frame is carbon fibre and some thing has shorted out and damaged all the ESC?
2. Also the new frame has much longer arms so I extended the cables from the ESC to reach the motors, (I have read that extending the cables to the ESC is not a good idea). Even if I remove the extensions now I still get the same results.



Thanks
 

OneStopRC

Dirty Little Hucker
Try removing the S-Bus from this unit, go back to wired... I have read people having issues with S-Bus on them receivers. I think it was with WKM's, but I would be interested to see if this is a receiver issue.
 

soler

Member
Try removing the S-Bus from this unit, go back to wired... I have read people having issues with S-Bus on them receivers. I think it was with WKM's, but I would be interested to see if this is a receiver issue.

I tried connecting the ESC directly to the receiver and have the same issue so I do not think it is Naza related.

Anyway to test an ESC?
 

OneStopRC

Dirty Little Hucker
I just find it odd, that 6 ESC's would fail on you..
When you power up the Naza, I take it your getting all the different flashes on the V-Sen LED? Should end with 4 green flashes I think.
 


soler

Member
I just find it odd, that 6 ESC's would fail on you..
When you power up the Naza, I take it your getting all the different flashes on the V-Sen LED? Should end with 4 green flashes I think.

Yes, getting the normal bleeps and flashes, also no error messages when connected to my PC via the assistant software

Don't you have to hit the link/mode to put it into S-Bus? possible you changed it some how and it is not working how it should?

Check this and make sure your receiver is set correctly.. http://manuals.hobbico.com/fut/r6208sb-manual.pdf

When I tested directly with the receiver I first plugged in a servo to make sure I was receiving a signal, I used the same channel with the ESC.

I will test the large capacitor on the ESC to see if that is working correctly.
 

OneStopRC

Dirty Little Hucker
I maybe wrong, but I thought, if these receivers was in S-Bus mode, the other outputs would only work on S-Bus servos? To test the ESC's, your going to need to take your receiver out of S-Bus mode!

DJI ESC's are not S-Bus compatible.
 



soler

Member
Hi All,

Well I got the new ESC (only ordered 1 to check) and the problem continued. Then I took the motors off the mounting plates and everything worked!!

Must have been shorting out the motors as the screws were too long. I really did not expect that to happen, i would have thought that they didnt not even turn.

Feeling like a bit of an idiot at the moment :upset:
 

soler

Member
Now it seams that in shorting the motors one or two may be damaged, They do not seam to spin up like before and on take off it seams motor 4 is giving very little lift and motor 5 is getting very hot.
 

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