Rewinding flipsky 80100 motor

larsb · Nov 9, 2019

I got an 80100 motor from flipsky. It was seized straight out of the box - cables have been pinched and shorted during assembly.

Anyway, i’ll rewind it with thicker wire and more copper so i thought i’d post the progress.

Original kV was measured with a drill press and voltmeter to 130.

All the parts look like ok quality besides that. Motor was really easy to take apart.

larsb · Nov 9, 2019

Reserved

larsb · Nov 10, 2019

Dimensions and specs
stator has 12 slots, 14 magnet poles
Axle dia 12mm
stator width 50.5mm
stator dia. 68mm
magnets circle / inner diameter in rotor:69.5mm
-->Airgap 0.75
lamination thickness:0.3
magnet length: 52mm
magnet width:11mm
Magnet thickness: 3.5-3.6mm (roughly, hard to measure since magnets are in a recess)
Winding: 7turns 88parallel/0.2mm wire (38mm2 copper/slot), delta connected.
Specified kV: 130
Measured kV: 130

Bearings: 1x6809zz, 3x6801zz, NSK japanese bearings

Halls: could be Allegro A3144E based on the marking but these are discontinued. Maybe a Chinese copy?
The hall board is glued in place with epoxy which will be an issue for the rewind, i’d like to keep it.
View attachment 3

larsb · Nov 12, 2019

Removed large bearing tonight. Can’t believe how they missed the pinched cable, means the factory doesn’t do any quality controls.

Flipsky will send me a replacement stator on warranty so that’s good.
View attachment 1
Motor is delta connected, i’ll reconnect it in wye if it fits the kV i want.

Winding looks pretty ok compared to the Revolt motors i’ve opened.

The end caps are really close to the winding, that might be a limiting factor on how much copper can actually be wound. Looking forward to getting the copper fill factor measured and calculated.

larsb · Nov 12, 2019

Stripped the copper. There’s some epoxy in it (very little) so i had to heat it in the oven to get all copper out, 120 deg C for 30 minutes was enough.

Weight is 330g for the complete winding
7turns x 88 parallel 0.2mm wires
Total copper area is 2.8mm2

That’s close to the Revolt rv120pro copper weight which was about 420g. Not bad for a motor that is half the size.

larsb · Nov 12, 2019

Crossthreading to Thuds’ excellent 80100 rewinding thread: https://endless-sphere.com/forums/viewtopic.php?t=20618#p300403

larsb · Nov 13, 2019

Original fill factor calculation:
slot size: 125mm2
7 turns x 2 sides x 2,8mm2 = 39.2 mm2
Fill factor: 31.4%

Phew, i thought it might be a lot higher as winding actually looks nicely wound. It would feel a bit awkward if fill was at 50% and i had stripped it but now I can easily improve it.

5 turns of 7 parallel x1mm dia wires would be 44% fill, connected in wye they'd give kV105. Doable in a relaxed way, i am not aiming for the max possible fill

larsb · Nov 13, 2019

Required wire length:

Turn length per phase
4*(5*50.5*2 +4*pi*8+pi*11)= 2560

Transitions length per phase
100

Exit wire length per phase
300

Total phase winding length: 2960
7 parallel wires —> cut length 20720mm per phase

larsb · Mar 30, 2020

tried the wind today, it was impossible :wink:

I forgot i used single tooth winding on my last winds, it really makes a difference. Even 4 turns was quite hard as the wire transits steal room in the slots and the 7 wires start to cross. 4 turns is 35% fill so slightly better than original but not great.. Also the smaller slots make it harder to compact the winding.

I wish i used high enough voltage to be able to do a single wire wind to full slots and still reach enough RPM for good power. I guess i could reach 60-70% copper fill with a wind like that.

larsb · Mar 31, 2020

Winding sketches with square wire, 19 turns 2x1 and 14 turns 2.5x1.25 respectively.

61% fill and 70% fill for these but kV will be too low.

10 turns of 2.5x1.25 will give kV 91 in delta which is OK and then fill is at a nice 50%, looks measly but still a 60% increase of copper from original winding

I think i’ll go with this on a single tooth wind and strip the previous winding, it wasn’t good enough.

larsb · Apr 3, 2020

calculating coil wire length based on the turn count and 150mm extra on each end of the coils for transitions and mistakes:
2*(5*61+4*66+1*70)+2*150=158cm

off to cutting!

Okami · Apr 4, 2020

Some very good info. Thanks for insights.
Also very nice models, clear to see everything.

In your opinion, what amperage can these 80 size motors do?

Still using 6360-6370 size motors but wondering about amp limits they can do.

I know this is purely depending on wiring, copper fill and other factors but what would be your average estimate?

This is without forced air cooling or fan blades, as that would improve the situation.

So far ive only managed to pull 32A from Turnigy Sk3 6374 for prolonged time, didnt have temp probe on it but it did get to level where holding hand to it for longer than 2-3seconds wasnt comfortable, so not burning hot but decently warmed up for sure

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larsb · Apr 4, 2020

i've run one of these at 200A max phase current for about 5000km, mostly commuting and some bursts of full power. Think it was kV130 motor. Above 200A you don't get much extra output (with this winding)

I wouldn't say they can take this continuous, commuting is very easy load.

larsb · Apr 4, 2020

I'll be trying DLRK evolution winding scheme, i think this will make it easier to do the winding and connections. Each phase pair is wound the same direction and transits are shorter than std dLRK winding.

Winding scheme and useful info found here:http://www.bavaria-direct.co.za/scheme/common/#prettyPhoto

larsb · Apr 4, 2020

That’s more like it! 50% copper fill, wasn’t hard to fit when all wires land perfectly.

Positive thing is that the slots can fit six turns on the bottom layer so 6+4 in only two layers should be doable on each tooth - this way the coils won’t start growing like they might do with more layers

larsb · Apr 5, 2020

Stator is glued on the carrier, it’s in the way for the winding so i’ll remove it with a bearing puller.

larsb · Apr 6, 2020

Lamination stack was hard to pull off - had to put it in the oven at 120 deg C and then use freeze spray before it moved at all even with the puller.
It stayed intact

Okami · Apr 19, 2020

So did u manage to put the new winding?

And how much more copper+/- u got to add this time?

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larsb · Apr 19, 2020

it's too nice weather

I am out trail running instead of winding motors..

10 turns of 2.5x1.25 will give kV 91 in delta and then copper fill is 50%, a 60% increase of copper from original winding

Okami · Apr 20, 2020

larsb said:
it's too nice weather
I am out trail running instead of winding motors..

10 turns of 2.5x1.25 will give kV 91 in delta and then copper fill is 50%, a 60% increase of copper from original winding

Nice weather is good argument for spending time outside indeed.

Why do u think more manufacturers dont use square wire in first place?

Is it that much more expensive? And if so by what factor?

I guess it is mostly suited for high performance, high efficiency motors then, similar as not everyone uses curved magnets nor always the strongest ones (though ive heard with higher strenght maximum allowable temperature decreases as well)

Not an motor expert myself but the details u have supported in your thread have been very informative and helpful

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larsb · Apr 20, 2020

It is much more expensive with square wire but the main issue (i think) is that it takes a lot more time to wind it. the thin wires can probably just be wrapped around and stretched by pulling vs the thick wire that needs to be formed, radius by radius, turn by turn.

Rewinding flipsky 80100 motor

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