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Pumpkin drop event

problem with 1400kv brushless motor

#1
Hi, recently I was flying my plane, and upon landing it, noticed smoke coming out of the left nacelle (2 engine airplane). I immediately unplugged the airplane and once I was able to tear open the bottom of the airplane, learned the ESC had caught on fire. I just now replaced the ESC, figuring the other one was cheap and getting old anyway and when I was testing the motors, saw that the left motor wasn't spinning, just jerking irregularly, and the ESC was getting hot, so I unplugged it and was fiddling around with the connections and prop when I realized there's a weird amount of resistance in the motor. I have no idea why though, it's weird. I now have it mostly disassembled, the bearings seem to be working and the shaft isn't bent, so it seems like some type of magnetic resistance, however this occurs when the motor is completely unplugged, and I can't figure out why. I assume this is the cause of the ESCs getting hot, as it's feeding the motor current but the motor isn't using it because it can't spin. any help is welcome and thanks for your time.
 
#2
Maybe we still don't know enough about this problem. I got a hextronic d4023 one of 4 that I had rewound then really wished I had checked because the stator rubbed the magnets on the rotor. Kinda like that motor, it's easy to wind with 21awg HP wye gives power limit of 18amps and figured some fixes for it's construction.

Bought some motors un-wound from iflight, used 3 of their pre-made 3.5mm connectors and thought I wound the motor wrong but hadn't made a winding mistake in a long time. Found one of their connectors was not soldered good...cold solder (and this caused funny back and forth oscillation).
Now since you said you disconnected the motor, the resistance, beyond normal cogging, ... could this be rotor and stator scraping like my hobbyking d4023 had?????

Heard of some products like dewalt saws self destructing because of a loose screw floating free in the motor.... something like this in your motor???? should spin free quiet with no noise just magnetic cogging. Could there be a loose part in there, a loose e-clip c-clip on one of the magnets, or the stator glued crooked, THIS really happened.

What if they got one or some of the magnets glued wrong way around, this would work against the controller which tries to deliver the rpms you demand at the throttle, so if it won't go that fast the controller just dumps more power into the motor.

You can measure expected power limits, like I know 2# should take about 110w, 3# takes about 220w w/ my motors 12v a123 batts and 12x8 prop. On the ground 2# static takes about 10amps, 3# takes about 17 to 18amps. Got an ammeter or wattmeter?


BAD solder connections, physical scraping parts, loose parts that don't belong ...... D4023--706.63kv 17t21awgHPyAdj 18a216w sun coll 4.png D4023--728kv and iFlight 3508q--653kv graf 11.png d4023 with common 22mm x-mount 2mm shorter.jpg

I test my motors the way I intend to use them, thrust and speed static at 2, 2.5, and 3# and power consumed


Hey pictures are really desired, wanted and great on a forum and so is follow-up.... what have you found now?


ProfessorFate


HP dLRK wye minimal dode pattern --- ODDS are wye bundle x200 term guide dark ph.jpg 12n14p Motor Winds HP adj coil wind wye is the best 2.jpg

You wanna rewind that motor or another one?
My new favorite wind I made up last month, the Half Parallel dLRK wye adj coil wind ... best ever...separates the fat sloppy even windings, the evens, you wind the odd first, leave the even hanging, wind the next odd head, then wind the even between. Circles are wound CCW.
 
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#3
Motors can feel strange and cogy when there is a short between two of the poles. For example, take two of the leads and connect them together. Harder to spin, right? That's because of the two poles fighting each other. This could be your problem.
 
#4
Maybe we still don't know enough about this problem. I got a hextronic d4023 one of 4 that I had rewound then really wished I had checked because the stator rubbed the magnets on the rotor. Kinda like that motor, it's easy to wind with 21awg HP wye gives power limit of 18amps and figured some fixes for it's construction.

Bought some motors un-wound from iflight, used 3 of their pre-made 3.5mm connectors and thought I wound the motor wrong but hadn't made a winding mistake in a long time. Found one of their connectors was not soldered good...cold solder (and this caused funny back and forth oscillation).
Now since you said you disconnected the motor, the resistance, beyond normal cogging, ... could this be rotor and stator scraping like my hobbyking d4023 had?????

Heard of some products like dewalt saws self destructing because of a loose screw floating free in the motor.... something like this in your motor???? should spin free quiet with no noise just magnetic cogging. Could there be a loose part in there, a loose e-clip c-clip on one of the magnets, or the stator glued crooked, THIS really happened.

What if they got one or some of the magnets glued wrong way around, this would work against the controller which tries to deliver the rpms you demand at the throttle, so if it won't go that fast the controller just dumps more power into the motor.

You can measure expected power limits, like I know 2# should take about 110w, 3# takes about 220w w/ my motors 12v a123 batts and 12x8 prop. On the ground 2# static takes about 10amps, 3# takes about 17 to 18amps. Got an ammeter or wattmeter?


BAD solder connections, physical scraping parts, loose parts that don't belong ...... View attachment 144589 View attachment 144590 View attachment 144591

I test my motors the way I intend to use them, thrust and speed static at 2, 2.5, and 3# and power consumed


Hey pictures are really desired, wanted and great on a forum and so is follow-up.... what have you found now?


ProfessorFate


View attachment 144592 View attachment 144593

You wanna rewind that motor or another one?
My new favorite wind I made up last month, the Half Parallel dLRK wye adj coil wind ... best ever...separates the fat sloppy even windings, the evens, you wind the odd first, leave the even hanging, wind the next odd head, then wind the even between. Circles are wound CCW.
thanks a ton or the help,
I don't believe it's unwound, however I could be missing something, the motor worked great up until I crashed the plane and had the ESC catch on fire, is it possible that some sort of current spike could have damaged it? here's a pic of the motor, as disassembled as I can get it, if you need any other angles just let me know:
 

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#5
Motors can feel strange and cogy when there is a short between two of the poles. For example, take two of the leads and connect them together. Harder to spin, right? That's because of the two poles fighting each other. This could be your problem.
it feels sluggish, and has a higher resistance, but it doesn't feel crunchy or erratic as though something's lodged inside it, how can I tell if the leads are screwed up, and if they are is it fixable?