Scorpion 2221-6 pulled 1075watts today, why?

[ranchhand]

Was flying my Trex 450 today, nothing hard. Did a loop, it got out of control and I got hard on the cyclic and pitch, the motor spin up a little higher than normal, about 3450 I think, then it got pulled down fast. It drew 1075watts and 91amps. This motor is only suppose to max at 525watts and 52amps. It shut down the esc and I crashed. The esc is a CC Ice 50 and current shut off was insensitive 80a.
Any thoughts why it would be doing that? Someone mentioned a possible short, I guess this would of been somewhere in the motor?

[ahahn]

Motors don't limit themselves. They will draw as much current as physics allows.

Specs are just the levels that won't destroy the motor. It is easy to exceed these levels.

You were saved by the ESC.

You should check how you have setup the heli, including pinion (gearing). Most likely you have over geared your setup, given the motor Kv and the cell count in your battery pack.

[Spunjah413]

Check you motor continuity by checking Ohms between each motor lead and the motor shaft/bell. As long as you aren't getting a reading, the motor should be good concerning a short.

You can also disable current limiting. Castle recommends either insensitive or disabled for heli use. Now granted this isn't the safest option, but it would not have shutdown during a short peak of high current.

[ahahn]

I would not choose disabled, simply because you are drawing too much current with no idea why.

Figure out what is going on. Like I said, my guess is you are geared too high for that high of a Kv.

[seefest]

Its not the gearing its an issue. I have xactly the same issue with the exact same setup. Heli has flown beautiful for months, just recently had motor cutout causing two crashes. One, an inverted climbout, and another a pitch pump. Different batteries both times. Plenty of juice in the voltz 45C pack. Haven't narrowed it down to motor or ESC yet. Any ideas?

[ahahn]

Originally Posted by seefest

Its not the gearing its an issue. I have xactly the same issue with the exact same setup. Heli has flown beautiful for months, just recently had motor cutout causing two crashes. One, an inverted climbout, and another a pitch pump. Different batteries both times. Plenty of juice in the voltz 45C pack. Haven't narrowed it down to motor or ESC yet. Any ideas?

Not sure you are having the same issue (maybe, but can't tell from your description). OP said he was overdrawing current (91A with 80A limit on ESC).

At least in his case, something is causing the excess current draw. There could be two possibilities (that I can think of), one the motor is shorting (or something is shorting) as someone has already suggested, or perhaps the ESC is losing sync with the motor. Losing sync often has a high pitch squeal associated with it, and it doesn't sound like this is what the OP had.

Anyway, I still don't suggest disabled for current limiting, mainly because we don't know where that spike was going before the ESC turned off.

I'd really check the motor over to see if it is in ok shape. Look at the magnets and make sure nothing is moving around.

Contacting CC and asking for advice might also be a good idea.

[ranchhand]

Well it was the gearing. The 12t pinion with the 121t main might of been alright with a 4000 rpm hs, but at 3250 it was just to much work for the motor. So I put a 10t on and ran it at 3350 and everything is happy now. I'm keeping current cut off disabled just in case. I'd rather lose the esc or motor instead of the whole heli.

[Digger1973]

Had the same issue on my -8. I found the motor shaft developed a slight bend, and the pinion wore out causing plastic dust off of the main gear to build up in the.motor creating extra drag. Replaced the shaft and the bearings, cleaned the buildup out, and all is well again.

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