Kosmik Hard Cutoff at 300A?!?

[DimitriV]

Hi everyone,

Today i had the first flight with the new Motor (Pyro 800-48Comp) on Cool Kosmik 200

-Gaui X7 10 T pinion
-14s
-Throttle 80% (about 2200 rpm)

After a hard Maneuvre the Kosmik Cut off.

Logview gave me Peaks around 300A

Is that behaviour normal?

[helicraze]

No not really this is 3rd time i hear pyro 800 cutting out on kosmik 200.
I pull 400a peak with scorpion motor and no problem

[Sonixs]

My Kosmik 160 cut off today at 185A. This was on a Scorpion ULT.

First emergency auto with the TDR which was uneventful thank goodness.

This was at 1700rpm and 75ish PWM.


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[smsodhi]

Maybe poor solder joints?

[jmackey]

The Kosmiks can handle a LOT. 300 for ImotPeak is no big deal. I log 460+ on ImotPeak and 320+ on Imot over and over on my Goblin 770 (Kosmik 160 and G2 KDE 700XF on 14S). Similar numbers on my 12S 7HV with Kosmik 200 and G3 700XF.

I've heard that the ImotPeak is a computed value. You should look at the Imot values instead for a measured indicator of amps going to motor.

Did your shutdown generate an error log? What did it say?
You would think that a K ESC and K motor would play nice with each other.

What connections do you guys have between your ESC and motor?
Flight pack to ESC?

I would check your solder joints and also make sure there is no arcing between motor wires and frame or each other. I've seen this occur at the bullet junction and it will shut you down.

[DimitriV]

The Guys in the German Forum gave me some great Tips.
I have to change the Ri comp to 9mOhm.
A user had the same Problem with this Motor.
After changing the Ri comp he had no Cutoff Issues any more

Kosmik Log:
motor stop: info #10 motor power limit reached
info #15 peak current limit reached
cut off #12 motor position lost

[NRPY]

What is an "Ri comp"?

[Wh1teAfr1can]

Originally Posted by NRPY

What is an "Ri comp"?

its resistance compensation. the default value is 4. for advanced tuning you can match this to the resistance of the motors winding which in the case of an 800 comp is around 9.

I am still really surprised that you were pulling spikes that large with an 800 motor on an x7 on 14s. if resistance comp helped I would check solder joints for cold solder as they will increase resistance.

You may also need to bump the p-gain to around 7 to compensate for spiky pwm.

[DimitriV]

I crimped the Yellow Esc Cable with the sanded Motorwires in a Copper sleeve, than i let the solder melt in the Wires.
I really pay a lot Attention to electric Connections.
So that can't be the Bottleneck.

Why should i change the P-value?

Do you have more Information about this Parameter, and what does it do exactly?

Thanks

[Wh1teAfr1can]

Originally Posted by DimitriV

I crimped the Yellow Esc Cable with the sanded Motorwires in a Copper sleeve, than i let the solder melt in the Wires.
I really pay a lot Attention to electric Connections.
So that can't be the Bottleneck.

Why should i change the P-value?

Do you have more Information about this Parameter, and what does it do exactly?

Thanks

when you increase the resistance comp the pwm inputs to hold rpm can overshoot and be spikey so by increasing p-gain this can be controlled. A value around 7 (default 4) should be about right for the increase in ri-comp

[DimitriV]

Thank you,

I will increase the p-gain to 7.
So, i should see less Amp Peaks in te Logs.

Very Interesting!

Wish that Kontronik would give that kind of Information with purchase of their Product.
Why don't they just put a Note in the MotorBox with prefered Esc Setup ?!?

For the Price we are paying for their Esc's and Motors, that should be taken for Granted!

If i knew that before, my X7 was still in one Piece

[Wh1teAfr1can]

Originally Posted by DimitriV

Thank you,

I will increase the p-gain to 7.
So, i should see less Amp Peaks in te Logs.

Very Interesting!

Wish that Kontronik would give that kind of Information with purchase of their Product.
Why don't they just put a Note in the MotorBox with prefered Esc Setup ?!?

For the Price we are paying for their Esc's and Motors, that should be taken for Granted!

If i knew that before, my X7 was still in one Piece

It is advanced governor tuning so it is not encouraged by the average user. I am still wondering how you pulled 300 amp spikes in a 3d machine on 14s especially a 700 size.

The default settings are very good.