We just can't have nice things

[Semi Pro]

So i fried my tekno/Nue 1515 2.5d this week and im kind of confiused as to why.

here is the deal, i have run it less than 30 times, it has never been over 90 degrees most of the time in my revo platinum geard for 35mph on 5cell

MMM v2 always on low timeing. after tearing it down the bearings are fine, there isn't and exposed wireing that could have ground out.

when it fried it was in my hot bodies lighting, the drivetrain spins freely so there wasnt any binding and the gear mesh was fine.

so heres what happened

i gave it alittle throtle, it kind of shuttered like it coged but then took off, it went 30 feet and made a sound like an outrunner does when breaking (some of you may know, its a very diffrent sound, almost like a arcing sound) and then quit, no smoke, very little fried motor smell, but over 300 degrees and the mmm wires were 210 degrees.

after it cooled i pulled it out and tore it down, it looks fine but the rotor isnt magnetic anymore

so this is the second motor that i have fried ever, both in this buggy both with this esc, im starting to think its the esc, what do you guys think?

anyone know what Nue will charge me to fix it?

im alittle afraid to use the esc again so i guess its going back to castle too

so guys what do you think caused the motor to fail?

[SunnyHouTX]

I can't see how the ESC can fry a motor in and of itself. Usually, a rotor gets demagnetized easily when the motor is geared too high and "over-volted".

[Semi Pro]

Originally Posted by SunnyHouTX

I can't see how the ESC can fry a motor in and of itself. Usually, a rotor gets demagnetized easily when the motor is geared too high and "over-volted".

agreed

and it wasnt overgeared or over volted

[FG101C]

Did the winding wires get squeezed together? I had one of the first Tekno/NEU's, before they put grommets on the wires at the can. It did pretty much the same thing.

[Ryu James]

thats what i was gonna suggest. is there any chance some of the copper wire coating could have come off and windings touched? just an idea but not even sure if that would cause the symptoms you had.

[SunnyHouTX]

^^^ (What they said)

[Semi Pro]

Originally Posted by FG101C

Did the winding wires get squeezed together? I had one of the first Tekno/NEU's, before they put grommets on the wires at the can. It did pretty much the same thing.

it has the grommets, i opened it again this morning and looked at extensively, all the windeings that are visable look fine, i removed the wire grommets to, the wires look fine under their, bearings are great, rotor has alittle magnitisim but no where near what it should ( not a suprise after seeing the temp)

i know the heat killed the motor but i dont understand why it went from fine to dead in 30 feet

oh well, its going back to neu monday morning

i will update you guys on what Neu has to say about it

[What's_nitro?]

You drove through a cloud of Dark Matter... That must be it!

[FG101C]

Is it possible that something on the buggy feels fine when you roll it, but is distorting and binding under power? Like one of the diffs, do you have another car to try that esc and another motor in?

[Semi Pro]

Originally Posted by FG101C

Is it possible that something on the buggy feels fine when you roll it, but is distorting and binding under power? Like one of the diffs, do you have another car to try that esc and another motor in?

the only way i could see that happening is if the bulkheads were twisting under power or if the bearings were going bad

i will try it with my tekin system if it stops raining today

[What's_nitro?]

I really don't think it's a mechanical problem. Nothing like that would cause such a dramatic increase in power consumption and leave the truck operable. I think it's the controller. Probably a defect in the feedback circuitry causing the timing to be extremely high, which would make the motor draw excessive current and heat up very quickly.

Now imagine the motor drawing that excessive current for the whole time you drove it, probably a few hundred-thousand revolutions, and therefore over a million pulses of extremely high current into the motor. It's an avalanche effect, because as the rotor loses magnetic strength it will draw even more current. You said it cogged a lot when it first started up, and the wires were really hot afterwards. That seems to support my theory.

It's kinda ironic, the FETs in the MMM didn't blow under the load. Maybe you can ask them just to replace the brain board in your controller since the FET board is fine...

[BrianG]

A faulty ESC can blow a motor if it is energizing a single phase constantly. But usually, the ESC FETs will blow way before the motor gets hot enough (from the excessive current) to demagnetize the rotor.

[What's_nitro?]

That's why I figure it was a timing issue. If it was a single phase short in the controller then it would have blown, I agree with that. He said the motor looked good inside, with no burned windings.

[Semi Pro]

Originally Posted by BrianG

A faulty ESC can blow a motor if it is energizing a single phase constantly. But usually, the ESC FETs will blow way before the motor gets hot enough (from the excessive current) to demagnetize the rotor.

thats what makes me wonder about the esc, you should have herd the acking sound it made, one of the other guys running at the pack 50feet away heard it.

i ran the buggy in the yard with my tekin system geared for 30mph.........thats the most i could gear for (damn 1400kv setup)

ran it threw 5000mah, motor was 88degrees, buggy ran great no binding

[_paralyzed_]

I feel your pain Semi. It seems like everytime I run some uber expensive component fails. It's never the cheap easy fixes that happen.

I've sworn I'd quit r/c numerous times after a costly mishap, but always come back.

I read more, learn more and try again.

What track and what classes do they have? I'd love to see your rigs in person