1515 2200kv heat issues in buggy

[What's_nitro?]

I just read the whole thread, and it sounds like your motor was bad from the start. A shorted winding in a motor WILL cause short runtimes/hot components/cogging no matter what your gearing/voltage/ESC settings. A bad ESC could have the same effect, but I think if it were the ESC you would've seen smoke by now.

Edit- Hmm actually you did say you tried another motor/ESC right? Is it possible they might be bad, too?

[KniteWulfe]

This is my second MMM 2200 combo. The first was replaced under warranty, the esc came apart and tore the wires from the board and the motor was testing out to 2700kv and running hot all the time.

My current symptoms were a bit different. The motor was fine and leveled off at about 140* until about halfway through the pack it would suddenly heat up and keep climbing to over 200 by lvc. Then I started getting cogging and power loss at about that same point but i had a heatsink and fan on the motor to prevent damage but esc temps were still under 160. Now the motor doesn't heat up because the esc is thermalling at about that same halfway point all of a sudden.

[What's_nitro?]

Weird... Well, if you've checked all the connections and they look sound, then I think you got a bad ESC and/or motor...(again?) Are the settings on the new ESC the same as before? High timing/start power would cause this with in-runner motors. Maybe try re-updating the firmware incase there was a glitch somehow.

Sorry to sound like a broken record. If the car coasts smoothly while off power then I don't think it's a drivetrain issue, unless, like you suggested, there is some strange on-power flexing going on.

Could you post a couple pics of the setup? It might help us help you.

[KniteWulfe]

I actually changed all of my connectors. I switched the traxxas battery jack to ec3, and went through and rebuilt the entire drivetrain for the 5th time. Settings are the same on the esc. Low start power, 0 timing, etc. I actually tried some punch but it made the cogging worse. I'll post an eagletree graph of what happens in a minute.

[What's_nitro?]

By "tried some punch" do you mean you increased the punch control %? Increasing the PC% would actually be less punchy, since you're adjusting the amount of control, not the amount of punch. In other words, 0% would be maximum punch.

[KniteWulfe]

I normally run no punch control but I tried 25%

Here are the graphs. Keep in mind that last huge voltage dip was in a chicane not on a straight. My LVC was set to 3.1 V/cell for this test. I also tried firmware 1.29 for this test and aside from maxing out at 138A instead of my usual 110-120 the results were the same as 1.24.

Volts


Amps


And the moment of shutdown including that huge drop in voltage:

[KniteWulfe]

I just thought of something. Those huge voltage drops coincide with glitches in my eagletree brushless rpm sensor which reads esc pulses. I'll post a graph with the rpm when I get home from work. I wonder if that could indicate an esc problem.

[KniteWulfe]

Here they are:

When the ESC died, same as the other zoomed graph.


RPM and V during a couple of the other glitches:


RPM and A:

[pinkpanda3310]

Something is not right there. Looks to me like you are using a 4s pack and getting over 50k revs from the motor.

16.8V * 2200kv = 36960rpm

[KniteWulfe]

Actually, something is causing the sensor to glitch. It reads the pulses from the esc to the motor, and since it is happening most often when I see huge voltage drops which sometimes don't even have an amp spike, I'm wondering if it could be a problem with the esc. Also I forgot to mention it reads 7k rpm at 0 but that is apparently normal for certain esc's and everywhere else is accurate. I think it might be when it's cogging that it glitches but I can't say for sure.

[pinkpanda3310]

So if i understand you correctly, with or without amp spike's the cogging and glitching and heat issues arise when the voltage drops too much? Does it only happen when the eagle tree is hooked up? (just had to ask) And the LVC is definitely set to 3.1v? If it was 3.4 that might cause issues (3.4*4s=13.6v). Just trying to think it through :) What if those glitches were not glitches but a problem of the esc? Hve you tried a better battery yet?

[KniteWulfe]

I've got some polyquest 4500 45/90C packs on the way. It happens with or without the eagle tree. The same batteries are fine in the mbx though. I've got my mmpro/1512 1800kv in the mp9 and ready for testing to eliminate the car as the source.

[KniteWulfe]

Here's the worst example of the glitching I have found. I don't know enough about FET switching and how the RPM sensor works to know if it really indicates a problem with the ESC. It might just be what cogging looks like. I got a little more run-time on this one but it still only used about 2300 mAh.

[KniteWulfe]

Well, after talking to tech support and describing what I saw inside my motor and the evidence of the plugs arcing it seems there is a problem with one of the phases in the motor. I wasn't sure if the separated windings and discoloration were normal but it turns out that's a pretty bad sign.

Anyway it looks like my problem has been solved, they have a new system for me on the way.

Once again castle impresses me with their service. They already had my complete brand loyalty but now its even more solidified. Its great to buy a product with so much confidence.

[What's_nitro?]

Yes... Make note of how that motor smells for future reference...

Castle service is second to none, but you already know that. I hope the third motor lasts a bit longer, though. Did they say anything about having a bad run of motors? It's pretty rare to have two defective motors in a row.