9920 Thermal - Cogging
 

Hey Guys,

I am running an 8XL with 9920 controller. I have had 2 or 3 thermal shutdowns and pretty bad cogging.

Do thermal shut downs happen to protect the esc or am I messing it up?

More Detail:

66 / 18 I have larger pinions on the way
12 cells
40 series tires
Stock receiver

I sure hope I didn't fry it. I will post some video soon if I can.

Thanks!

:002:

im pretty sure that a esc goes into thermal shutdown to protect it

Yes but heat can also make the electronics become badly efficent making it stutter too but if your running only on 12 cells for a 8XL it can't be to do with heat.

check gearmesh and to see if the truck rolls freely

That is what I have read here in the forums. I don't have a temp sensor, but I could not hold my finger on it for more than a couple of seconds. It also runs well for the first couple of minutes starts cogging, then it stops responding until it cools.
:020:

Seems OK.

Thanks.

Do you have a pic of how itis mounted? Have your tried other receivers? Check your wires and stuff as well. Did you try some other batteries? It should not be a heat problem with the setup unless something is not right. But If the cogging can cause heat problems as well.

I have posted some High Res pictures.
Warning - Pictures are Huge
http://www.rustyonline.net/html/rchirez.html

Thanks to everyone for the help!

the pictures are a little big but they are good quality
i would recommend getting rid of those rpm arms

I plan on replacing the RPM stuff. I just want to figure out this cogging issue first.

Thanks

try getting the receiver off of the aluminum. that could very well be your problem.

I will give it a shot.

I posted a video at the site where the pics are.

Thanks

Pictures and video posted
http://www.rustyonline.net/html/rchirez.html

I have gone through the wires and checked solder. Seems to be OK.

I have tried multiple sets of batteries.

Thanks!

Steam???
 

I believe there was steam coming out of the caps (516K0).
Is that what they do when they cook? Funny thing is that it still works???
I thought it was smoke, but it wasn't. I stopped running it and the steam stopped. Ran it again steam started to come out again.

http://www.rustyonline.net/assets/images/9920-1.jpg

Hello. I don't have any experience with BL ESC's, but I do with electronics in general and those caps look bad. See how the tops are rounded? That means the electrolyte has expanded. This can be caused by age (usually 5-10 years, sooner if they are run at very close or just over their rated voltage), running a higher voltage than they are rated, or reversing polarity. The "steam" you saw was probably electrolyte gas escaping.

Capacitors are used to either pass a certain range of frequencies, or to smooth out voltage transients for a more constant current and voltage. I don't know of their function in that circuit, but since they are where the battery wires enter, I would guess they are being used to filter out noise entering the battery wires. They are too small to provide the transient function judging by the amperages the controller will require. Either way, they are needed and that is very likely what is causing your problem.

There are two ratings for a cap: voltage and "farads" usually expressed as uF. All I can see in the picture is 516k0, but on the other side, you should see the ratings I'm talking about. Most electronics shops (RadioShack) should carry those if you feel like replacing them - just be sure they are installed correctly. The white stripe denotes the negative lead.