Mamba Max... Did I Kill it?!?

I bought this engine and speed controller about 3 weeks or so ago, and ran about a week with it, never had any temp issues except for an end on one of the connectors to the engine came off... broke another part on my truck and decided to get a lipo battery. The battery came yesterday, it's a 6000mah 3s Lipo. It was pretty fast, kinda scared me so I followed advice on the website and replaced the pinion gear in my truck with a 15 tooth, spur gear with a 86 tooth (to tone it down says... small pinion, large spur) and took the truck out yesterday afternoon and drove it around a little, after about a 15-20 min run I noticed it would start limiting my acceleration with the 9v cutoff. I charged the battery and went out for a bit today, drove a little bit maybe 10-15 mins again... took a break and when I came back out... the ESC armed, but when I gave it a little throttle forward or reverse... the wires seemed to jump/pulse a little along with the tone (heartbeat kinda)... esc made a beep like it wanted to go... but nothing from the engine. I spin the rear wheels (holding both cuz of the differential) and it doesn't seem like the engine is seized or anything... just won't turn. A couple of second or two bursts on the throttle tho... heated up the wires on the battery and going to the engine... must be a lot of juice in there to make the wires jump like that?

I've read on a few forums about watching heat on the engine etc... and the highest I've seen temperature go was 180. So... I dunno if I have a problem with the ESC or just the engine... whether or not I should return it for replacement/repair... or what to do.

I did have... 10% burst limit set, 10% drag brake, lowest timing setting on the engine, and medium setting for start power.

Did I kill my engine?!?

[glassdoctor]

I don't know what's going on here... but I have a couple comments...'

The wires getting hot indicates an internal short of some kind, and I can verify that this happens when the system has severe cogging. And it will happen if a motor wire touches a battery lead wire.... :(

What I curious about is that you say the wires "jump".... I can't get my mind around that one. I don't think that can happen from electrical current. Maybe there an EE here that can say otherwise, but I've never seen or heard of that.

Can you test the esc with another motor? That would at least tell you if it't the motor or esc.

What I curious about is that you say the wires "jump".... I can't get my mind around that one. I don't think that can happen from electrical current. Maybe there an EE here that can say otherwise, but I've never seen or heard of that.

Can you test the esc with another motor? That would at least tell you if it't the motor or esc.

When I give it throttle, forward or reverse... the esc beeps with like a heartbeat... and the wires actually pulse... I leave off throttle right away as they get hot almost immediately.

[coolhandcountry]

I think I would pack the whole system up and send back.
The motor may be bad but may have done some small damage to esc.
The esc may be bad and done small damage to motor.
Just something to think about.

[jhautz]

You said that one of the connectors to the motor came off at some point. Did you solder it back on or what exatcly happened? Sounds to me like its severe coggin, like what you would get if the motor only had 2 of the 3 phases connected. I would double check all of your connections on both the motor and the battery sides. Give all of the solder joints a good hard tug. If they are correct you will not be able to break them. Also check that the plug itself didn't get damaged when it came off the first time. Or it might have been damaged and thats why it came off in the first place.

Bottom line make sure all of your plugs are good and your solder joints are solid.

This problem really sound to me like its a connection loose somewhere in the system. Probably on the motor side.

Just my opinion.

[natrix]

The "moving motor wires" phenomenon happened to me when my Quark 125b fried. I'd send it in for replacement.

[BrianG]

What causes wires to move? Extremely high current AC signals. The magnetic fields produced by this interact with each other. Since AC changes polarity and each phase is at a different point of the signal, the wires move. Don't forget, much of a motor's "resistance" is formed by back EMF from a moving magnet. If the rotor doesn't turn for whatever reason, there is very little back EMF and the current is MUCH higher. The FETs don't blow up right away because they can actually handle a lot more current than they are rated, for a short time. No wonder why the motor wires get warm!

If the ESC goes bad and sends a conflicting signal to the motor, the motor won't turn effectively locking it. If it doesn't turn, there is only the pure DC resistance of the windings limiting the current.