Pixhawk / Tx or ESC problem - motors running way too fast

Flydigital

Flydigital

Member
I think I have everything correctly set up but when I arm and power up the motors (without props) scream into action. Very sudden and very powerful If the props were on it would shoot through the roof!
Where might my problem lie?

Pixhawk flight controller.
8 x 45A multistar ESCs
8 x Multistar 330kV motors.
6s lipos

I have the controller configured and testing with 'stabilise' flight mode.
I've calibrated the ESC throttle range and calibrated RC stick range too.

I'm hoping I can dial it down but not found out where. Ideally it should power up at an idle RPM at midpoint, then once airborne the midpoint RPM should be higher to keep it in the air.

Thanks for any help!
 


Flydigital

Flydigital

Member
Thanks. I've tried those settings but nothing seemed to change. I then tried reducing to zero along with the min throttle too but no change. I think I need to try another parameter that can confirm the process is actually working - ie that I am actually able to change parameters and see the results. I will look through the options more carefully to check it's working.
 

Flydigital

Flydigital

Member
Well I've had a look through and don't see any other parameters I can verify as they all seem related to flight.
I've tried changing MOT_SPIN_ARMED, THR_MAX, THR_MID, THR_MIN.
Eventually reducing all values to zero.

Each time I arm I get a tone. No rotation but on slow increase of throttle at about 25% it suddenly starts, very fast. Then at 50% extremely fast - screaming. Beyond 50% it can go even faster but feels like it's probably doing some damage.
Not sure what I can do next to resolve this?!
 
Last edited by a moderator:

Flydigital

Flydigital

Member
Managed to get somewhere. Seems like HR_MAX, THR_MID, THR_MIN do effect changes. You need to turn system on and off for it to have any effect.
 

R

R_Lefebvre

Arducopter Developer
Hello,

Do you have previous MR experience? I'm just curious about what you mean by the motors are screaming. What you're describing is very odd. There should not be any problem like what you are describing unless you have set up your system improperly.

Which flight mode are you testing in?

Rob
 

Flydigital

Flydigital

Member
I have limited experience. Up until now it's been a F550 which has 920kV motors on a DJI Naza. It's an assembly job but relatively easy as it's all designed to work together. This time I been more ambitious with a huge 8 motor 320kV power. When I first armed the power and noise I think freaked me out plus I didn't know the pixhawk at all and all it's parameters. So the 'screaming' is not accurate. Actually I have just done a first indoor power up with blades on. The screeching is replaced by epic fan turbine noise. I'm in stabilise mode and taken it to the point of just airborne.
I plan to try a flight shortly but will read up on auto tune and 'PDI'.

So is stabalise the best flight mode to begin with? From a DJI position is it like manual or atti? GPS for some reason they say don't do until you get stabilise and alt-hold conquered.
Glad to be getting somewhere!
 


SAL568

SAL568

New Member
Flydigital said:
Managed to get somewhere. Seems like HR_MAX, THR_MID, THR_MIN do effect changes. You need to turn system on and off for it to have any effect.
Click to expand...
Hi there is a video on the 3DR support site that walks you through the steps to sync and tune the motors. Without the props on motors will be a bit faster to respond to throttle inputs as the motors have no props to drag them down
 

Flydigital

Flydigital

Member
I managed to get it working in the end. I know there is also an autotune routine which I will try to get it just right. Thanks
 

You must log in or register to reply here.
Top