Turnigy CA120-70-15 with Monster 2000 controller

[DaleKramer]

See attached test data.

Other than trying a second Monster 2000 controller to see if the controller is bad, can anyone suggest a potential fix for the fact that the controller just seems to cut out randomly?

Only option we haven't tried to fix problem is the PWM switching rate, could that be it?

Latest test was:

Low cut-off voltage = 36 v
Current limiting = insensitivity
Brake Type = soft
Timing = High 15-30 degrees
Cut-off = soft
Soft start = soft
Governor mode = auto
PWM switch rate = low

 

[Jeremy Harris]

My guess is that this controller is pretty typical of the relatively cheap, supposedly high power, stuff branded with HKs own label. I've yet to see any controller with that brand label perform close to the supposed spec figures and suspect I'm not alone. My guess is that the Turnigy Monster *might* handle short duration peak phase currents of around 200A, which equates to a running current of maybe 70 to 80A from the battery. In all probability it can't handle the low inductance/resistance combination that the CA120 motor presents, even for no load acceleration, which is why it's cutting out.

That motor is a controller killer, as others here have found, and needs a very good controller to tame it. Nothing short of something like one of the big Castle Creations controllers is likely to do the job, I believe. The motor is going to demand peak phase currents that are up in the 300 to 400A range during acceleration, something that these relatively cheap Chinese controllers aren't good at supplying.

Others will probably chime in here, as a few people have now played with these big motors and discovered how hard they are to drive well. The best results so far seem to have come from fitting sensors and running the motor on a really big controller, preferably with Burties magic timing adjuster.

Jeremy

 

[Hillhater]

.....the controller just seems to cut out randomly?...

What are the symptoms of the cut out ?
What has to be done to reset /restart the motor after a cut out ?
Are there any fault indications /noises from the controller or motor ?
could this be a sync failure cut out ?

 

[DaleKramer]

What are the symptoms of the cut out ?
Mostly just like throttle cut quickly, sometimes with a little buzz.

What has to be done to reset /restart the motor after a cut out ?
Nothing, just jockey throttle a little catches it before it stops altogether.

Are there any fault indications /noises from the controller or motor ?
No lights or controller beeps.

could this be a sync failure cut out ?
I am the wrong person to ask this of.

 

[Hillhater]

sounds much like a sync failure ..
Try a few different combinations of PWM and timing to see if that helps.
Otherwise it a Castle HV ESC needed !

Odd that you should have this problem when driving a prop though ?

 

[liveforphysics]

It appears if you get a stiff enough pack, that motor will easily reach 10kw on only 12s.

That tells me 20kw, or more, should be possible on a healthy 24s pack.

 

[Jeremy Harris]

Odd that you should have this problem when driving a prop though ?

I suspect the problem is just the massive peak phase current that the motor will draw when trying to accelerate the inertia of the rotor and prop. Although the low rpm power demand will be low, the instantaneous torque demand will be pretty high, even with no load. This may well be enough to cause the controller to crap out.

Maybe I'm just unlucky, but all the Turnigy brand ESCs I've used have smoked, often without being abused in any way. One of their 100A ones got too hot to touch when running at less than 30A, which makes me very suspicious about their claimed current specs.

Jeremy

 

[olaf-lampe]

You definitely have to use the fastest PWM frequency available. Then start with the most advanced timing and step down to the point, where the no load current is lowest.
Than use the servo speed adjuster from hobbyking ( http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=8863 )
to protect the esc from loosing sync. For explanation read this thread : http://endless-sphere.com/forums/viewtopic.php?f=28&t=21552
Adjust it in a way, that it accelerates fastest without tripping.

Good luck
Olaf

 

[DaleKramer]

Great ideas!

I will test higher PWM, throttle ramping and report back.