Critical Overheating Of Esc!

[Chutneypundit]

Hi. A mate came over - just into the hobby, and has a Ansman Mad Rat RTR. He's run it a few times. We connect everything as per usual. Motor doesn't turn. After a while we smell hot plastic/solder. Turn everything off and ESC is so hot it's spitting molten resin! We undo everything, check everything. No joy. He goes intot town and buys a new MTronics RV15 (motor on MAd Rat is a Clash 15). We check everything, connect everything. Still no joy. We connect to a 540 just lying around and everything works. So it's the motor, we think. I happen to have a Clash 15 lying around, so we swap out the motor, checking drive train is free in the process. Conect everything up. Yippeee! it works. We go down to track in the garden and have been racing around happily for about 5 minutes tops, when Mad Rat starts belching smoke and body is aglow with flames from within. Rapid and careful unhooking, unplugging, etc. and new RV15 ESC has turned into a small volcano, spraying interior with balls of molten solder and resin. We've checked everything, and have assembled ESC and gubbins myself, several times on 6 different models and I can't figure out why this would be doing this...?

Any ideas, anyone?

[Jonny Retro]

... new RV15 ESC has turned into a small volcano, spraying interior with balls of molten solder and resin....

Cool! Have you got any photos?

Um, I mean, oh no! How Tragic!

The only thing I can think of atm is gearing - as in overgeared (too large a motor pinion = good top speed but poor accelleration). If you've been running it on relatively slipperly surfaces (dirt, sand, gravel, wet tarmac) in the past then it wouldn't be so much of an issue, but if you've been running it on grass today (high drag) that could explain it. Another possibilty is too tight a mesh between the motor pinion and spur gear, creating lots of extra resistance in an otherwise "free" drivetrain.

Telltale signs for the above would be motor heat - in the excitement I guess you wouldn't have checked, but the "three second rule" applies - if you can't touch/hold it for at least three seconds, then the motor is _way_ too hot. Once it's cold you can look for signs of heat damage - blueing/purpling of the wires, brushes &/or shaft, and/or melted insulation on the wires, etc.

[Chutneypundit]

Cool! Have you got any photos?

Um, I mean, oh no! How Tragic!

The only thing I can think of atm is gearing - as in overgeared (too large a motor pinion = good top speed but poor accelleration). If you've been running it on relatively slipperly surfaces (dirt, sand, gravel, wet tarmac) in the past then it wouldn't be so much of an issue, but if you've been running it on grass today (high drag) that could explain it. Another possibilty is too tight a mesh between the motor pinion and spur gear, creating lots of extra resistance in an otherwise "free" drivetrain.

Telltale signs for the above would be motor heat - in the excitement I guess you wouldn't have checked, but the "three second rule" applies - if you can't touch/hold it for at least three seconds, then the motor is _way_ too hot. Once it's cold you can look for signs of heat damage - blueing/purpling of the wires, brushes &/or shaft, and/or melted insulation on the wires, etc.

Less of the cheek! ;op

It's running the gear setup that came out-of-the-box RTR, and on loose dirt...

[Champ85]

What type and voltage battery are you using? NiCd, NiMH, LiPo? 7.2V, 8.4V, 8.4V, 9.6V, 11.1V, 14.4V?

From your description, such a nasty "blow up" like that points to three possibilities: Reversed polarity or too much voltage or short circuit. Since you state it ran for 5 minutes, reversed polarity cannot be it, which leaves voltage and short circuit. Are all wires and connectors protected by insulation or heat shrink tubing?

[mongoose1983]

I'm having the very same problem. My late 80's Futaba MC210CB ESC gets very very hot and will not do a thing!

Any info on what is causing this would be very appreciated.

You all have a great Sunday!

EB

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[Chutneypundit]

What type and voltage battery are you using? NiCd, NiMH, LiPo? 7.2V, 8.4V, 8.4V, 9.6V, 11.1V, 14.4V?

From your description, such a nasty "blow up" like that points to three possibilities: Reversed polarity or too much voltage or short circuit. Since you state it ran for 5 minutes, reversed polarity cannot be it, which leaves voltage and short circuit. Are all wires and connectors protected by insulation or heat shrink tubing?

We're using Powertech NiMH RC3000 6 cell stick pack. We're using the same standard 'Tamiya-tyoe' connectors that it ran with happily for ages out of the box. Yesterday I dragged out a pile of old RC bits, and we've cobbled together a whole new control system. Of note was that we had to replace the receiver as it had ceased to receive a signal (crystal was ok, as that's what we're still using). So far it's run fine, meaning the gearing etc. must be ok. W'd double-checked polarity of leads to the receiver, but still, I feel it was the receiver that was at fault somehow, as it was the only part we didn't swap out, when the second ESC erupted.