ESC fried - how should I troubleshoot?

[dure16]

Whenever I purchase a used motor, I plug it into the nearest ESC to check that it works properly. Well this time that process didn't go so well.

I powered on the ESC, checked that steering worked, and then gave about 50% throttle. The naked motor shaft started spinning for 1-2 seconds and then poof. Lots of smoke and sizzling noises from the ESC. I quickly unplugged everything and threw the car and battery in the yard.

ESC damage: two motor bullets completely detached. The negative battery wire detached from the ESC and the positive battery wire detached from the connector. All were clean breaks - it got hot enough to melt the solder.
Motor damage: a little charring near the bullets. Nothing serious. I can't find anything wrong inside the motor.
Battery damage: none that I can tell. It was warm but cooled down quickly. Cells are balanced at 3.8V.

56113 780kv motor
MMX6S ESC
HRB 6S 5ah 60C
EC5 connectors

I have some questions about what to do next:

1. I assumed the current demand would be minimal under no load and therefore safe for that ESC (even with a huge motor) - was that assumption wrong?
2. Can a defective motor cause this problem? How should I inspect the motor?
3. Can a defective battery cause this problem?
4. How can I troubleshoot further without risking another ESC?

 

[Hector_Fisher]

I would try using the ESC again first with a different motor. If the esc still works with the different motor, then I might test the original motor you bought on another esc. I cant imagine why the esc would do that unless it fried itself like a spektrum.

 

[Mikeeeeeeeeeeeeeeeal]

That's a big motor.

 

[dure16]

I would try using the ESC again first with a different motor. If the esc still works with the different motor, then I might test the original motor you bought on another esc. I cant imagine why the esc would do that unless it fried itself like a spektrum.

I should've clarified - the ESC is toast. Melted. Missing two bullet connectors and battery wire.

 

[Tex Koder]

I should've clarified - the ESC is toast. Melted. Missing two bullet connectors and battery wire.

Pics of such damage..?

 

[K-BASH]

Esc is done..coulda been motor or damage to each over time..castle esc will get damaged little by little if there's any current restrictions till this happens..I've burnt up probly 20 castle escz..out of them 20 only 1 went up in car...every other went up on startup an I've always got things unplugged in time....I'd guess it was just it's time to go.....your options now are send to castle an get new 1 for about 110$ an either sell it or run it....or ya can upgrade to bigger esc....mmx6s is the worst esc outa the mm2,mmx6s,mmx8s xlx2....they stink bad huh....99% of mine went up same way..
Xlx2 without exposed mosfets really puts on a hell of a light show..ya hear sizzling bacon sound she's going..lol

 

[dure16]

Pics of such damage..?

I'll post a pic later today

Esc is done..coulda been motor or damage to each over time..castle esc will get damaged little by little if there's any current restrictions till this happens..I've burnt up probly 20 castle escz..out of them 20 only 1 went up in car...every other went up on startup an I've always got things unplugged in time....I'd guess it was just it's time to go.....your options now are send to castle an get new 1 for about 110$ an either sell it or run it....or ya can upgrade to bigger esc....mmx6s is the worst esc outa the mm2,mmx6s,mmx8s xlx2....they stink bad huh....99% of mine went up same way..
Xlx2 without exposed mosfets really puts on a hell of a light show..ya hear sizzling bacon sound she's going..lol

It smells so bad. Had to change my clothes and air out the basement for hours.

You wouldn't have any concerns about plugging that motor into a different ESC?

 

[LibertyMKiii]

I have some questions about what to do next:

1. I assumed the current demand would be minimal under no load and therefore safe for that ESC (even with a huge motor) - was that assumption wrong?
2. Can a defective motor cause this problem? How should I inspect the motor?
3. Can a defective battery cause this problem?
4. How can I troubleshoot further without risking another ESC?

1. I assumed the current demand would be minimal under no load and therefore safe for that ESC (even with a huge motor) - was that assumption wrong?
While this shouldn't be an issue and you said it was limited to 50% throttle the Castle ESCs don't seem to like spinning unloaded motors. Just my observations, but it honestly seems like the ESC was faulty and an arc occurred inside. I would assume a manufacturing defect.
2. Can a defective motor cause this problem? How should I inspect the motor?
If the rotor and windings look ok it is likely the motor is fine. Look for burn marks.
3. Can a defective battery cause this problem?
I wouldn't think so since it powered on without error warning and things were working fine for a while.
4. How can I troubleshoot further without risking another ESC?
There is a trick where you spin the motor with a drill and take measurements from 2 phases of the motor with a digital multimeter, and then compare when connected to another 2 phases of the motor. This wouldn't be a bad idea.

 

[gotnitro]

How to troubleshoot a fried ESC Nitro style.

Rip it out and chuck it as hard as you can in any direction not caring what it might hit.

That about sums it up for me.

 

[Johnny b]

Esc is done..coulda been motor or damage to each over time..castle esc will get damaged little by little if there's any current restrictions till this happens..I've burnt up probly 20 castle escz..out of them 20 only 1 went up in car...every other went up on startup an I've always got things unplugged in time....I'd guess it was just it's time to go.....your options now are send to castle an get new 1 for about 110$ an either sell it or run it....or ya can upgrade to bigger esc....mmx6s is the worst esc outa the mm2,mmx6s,mmx8s xlx2....they stink bad huh....99% of mine went up same way..
Xlx2 without exposed mosfets really puts on a hell of a light show..ya hear sizzling bacon sound she's going..lol

Was that mommy's birthday present? She enjoy it?

 

[Moirae]

Lol I'm surprised you even tried to hook that motor up to that esc. I would have been scared to even try it for fear of exactly what happened

 

[dure16]

4. How can I troubleshoot further without risking another ESC?
There is a trick where you spin the motor with a drill and take measurements from 2 phases of the motor with a digital multimeter, and then compare when connected to another 2 phases of the motor. This wouldn't be a bad idea.

Thank you. What would I be checking for with this test? Inconsistency between phases?

Lol I'm surprised you even tried to hook that motor up to that esc. I would have been scared to even try it for fear of exactly what happened

Live and learn

 

[#ARRMArcfanboy4life]

This is how to properly troubleshoot a esc

 

[K-BASH]

Was that mommy's birthday present? She enjoy it?

It was,my damn kids write on everything.lol

 

[RCbuzz]

Lol I'm surprised you even tried to hook that motor up to that esc. I would have been scared to even try it for fear of exactly what happened

Curious why is this bad? I have tested free spinning larger motors on smaller ESC's in the past (Hobbywing) with no issues. Is this a Castle thing?

 

[K-BASH]

I'll post a pic later today

It smells so bad. Had to change my clothes and air out the basement for hours.

You wouldn't have any concerns about plugging that motor into a different ESC?

Really sucks when ya gotta throw burntbup esc in trunk of car to drive back home....car stank for weeks...I'll never do that again...I'll drive home with esc in hand hanging out the window....if there wasn't a core on esc I'd long arm it far as I could throw it

 

[LibertyMKiii]

Thank you. What would I be checking for with this test? Inconsistency between phases?

Yep exactly.

Curious why is this bad? I have tested free spinning larger motors on smaller ESC's in the past (Hobbywing) with no issues. Is this a Castle thing?

Just a hunch at this point, but yes I think its a castle thing

 

[Moirae]

Curious why is this bad? I have tested free spinning larger motors on smaller ESC's in the past (Hobbywing) with no issues. Is this a Castle thing?

Honestly I don't know why it's bad. It just seems like a bad idea to me. I see big motor and small time esc and in my head that just seems like something that's not going to go together. I have no scientific reasoning behind it, I'd like to say it's just common sense or something to me but I dunno. Just the idea makes my spidey sense tingle lol.

 

[Hector_Fisher]

No-load current is a thing, it exists (it can even get the motor can to warm up quite a bit)

But it's not typically so "dramatic", like in a matter of seconds. Usually takes a bit of spinning, and it's the motor that heats up, not the esc exploding.

If I had to guess, i would bet its something to do with castle specific ESCs, as mentioned above. Something like KT kept finding out multiple times with his XLX2's.

It's a shame they're so reactive to seemingly random conditions or situations.