How/why did this go boom, and how can I prevent it...

[whitrzac]

55t integy crawler motor
4s
HH brxl, quiet mode, holmes hold on.
TF2 SWB
Geared to run ~5-6mph
Had enough torque to pick up a ~8lb truck when holding a back axle.

This started smoking on the flat, level trail on the way back. I was pulling a friends truck that had broken a driveshaft. It was free wheeling. Motor never got warm. Just smoke.

[mikebecher]

Because 55t integy crawler motor.

If it's this one Matrix Pro Lathe Motor 55T Single Wind, 540 Size for R/C or RC - Team Integy it's only rated for 12v DC.

[EeePee]

Scale your problem up to Formula 1 levels and that's like asking why did a crankshaft bearing fail in Lewis Hamilton's new Mercedes engine. The conclusion is, shit happens.

And I've ran 55 turn Integy motors on 6S. It's about the rpm more than a voltage rating.

[Scotski]

Look at your commutator. Brushes probably looked bad too I'm sure. How short are they? If they get too short they will not contact well and can cause that smoking. Cheap motors come with cheap brushes and 4s input will for sure burn them up fast. I'm not even sure how many if any brushed motors can handle 4s for long. I have never gone over 3s on a brushed setup and a few of them got hot as hell rather fast.


Here is an example of a worn out commutator(top), a burnt comm(mid) and a good commutator. Notice the colors of the windings due to heat/poor electrical connection. All of these motors were only run on 7.2 NiMh batteries too. I can only imagine what 4s would do and how quickly.

[WHITE-TRASH]

It burned up because it's a cheap motor and because scale nerd. Pick the broken truck up and carry it. Lemme guess you winch when stuck too?

[Scotski]

Originally Posted by EeePee

Scale your problem up to Formula 1 levels and that's like asking why did a crankshaft bearing fail in Lewis Hamilton's new Mercedes engine. The conclusion is, shit happens.

And I've ran 55 turn Integy motors on 6S. It's about the rpm more than a voltage rating.

I see what you are saying, Eeepee, and I do not disagree with you. Shit does happen and with electronic devices it happens more often than we'd like. Even geared down, on 4s that 55t motor is screaming full throttle. Gearing does not change the rpm output of the motor at full throttle, only the end result at the wheel. Be that as it may, brushes wear fast under speed and stress, plus...dirt. Dirt kills and the dirtier the brushes and comm get, the worse the connection and the faster they wear out, especially when accented by high voltage/rpm application.
I have no idea why anyone would run a trail rig on more than 3s really(although making my Gelande Cruiser ride wheelies was a bit impressive), but sometimes we just want that mad power when we want it even if we are throttled down 99% of the time.

[Scotski]

Originally Posted by WHITE-TRASH

It burned up because it's a cheap motor and because scale nerd. Pick the broken truck up and carry it. Lemme guess you winch when stuck too?

Wait! I think we're all scale nerds lol! And...I for one hate having to carry my truck. Damn 10 lb. rig gets heavy after a 1/4 mile trek out of the crawl zone back to your 1:1.
Carrying your scaler...oh, the humiliation! Especially if it died without being a major crawling rollover with batteries flying out and your driver becoming impaled on some thorns.

[WHITE-TRASH]

Scale nerdin' ain't easy I guess. I don't mind carrying my sportsman since it's not laden down with 42 points of flare zip tied to it with a WWE doll behind the wheel.