Rewinding of Emax MT2204 motor wires…
Rewinding of Emax MT2204 motor wires… by David HK January
2017
Like most people in the DIY quadcopter world, having flied 3S Lipo for almost a year, so I tried 4S, with 20A ESC. So
powerful, so more energy! But without realizing 6 inch props + 4S could produce
smoke! Especially 6045 props! I didn’t see any smoke, but after flying a few
times, I start seeing motors not working, and eventually 2 Emax MT2204 motors were
dead!
So I bought a set of 4 kingkong 2205 2300kv motors, which
can support 4S. Guess what, 1 ESC
(Emax 20A, the heavy and big version) went dead!
Anyway, back to motor rewinding. Since I have 2 dead motors to play with, so I
researched and learned about motor rewinding.
Specifically, the below discussion is most useful and clear:
Further down the discussion, starting from #39, the Delta
Variant, where the wires emerge next to each other, is even better and bomb
proof to follow and ensure you are in the “right direction” so to speak!
Note that the original Emax MT2204 is using 0.1mm folded x3 wires
at 17 turns. I don’t like 0.1mm wires,
too fragile, it can break easily if you pull it just a little bit hard. So I bought 0.21 winding wire.
My 1st attempt was using x3 wires folded and
making 12-13 turns, but it ended up too thick and touching the top belling and scratched
the wires.
My 2nd attempt was using x2 wires folded and 12
turns, but I wasn’t double checking on the winding direction and just follow
the initial dLRK approach, it ended up not spinning at all!
My 3rd attempt was also using x2 wires folded and
12 turns, and this time follow the Delta Variant method, and printed out the
wiring direction diagram and follow it successfully! I found with a printout of the diagram really
help, as I can turn the paper so that the teeth I working on is in the same angle
as in the paper, so minimize any chance of “looking at the different angle”.
For x2 wires 12 turns, the wire length (x2 folded) I cut was
76cm each (you can add 1 or 2 cm as a buffer).
Thrust Testing:
Using an old 2200mAh 3S 35C battery, original emax nighthawk 6045 prop, 30A ESC, kitchen scale, prop mounted upside down but still in the flying direction (ie the uplift side but upsidedown is still in the direction of the motor spins), so it will produce downward force instead of uplift force. Here are the results:
Original Emax MT2204 2300kv: 560g, 19Amp
Rewinded Emax MT2204: 540g @19.5Amp
So they are similar in performance, but the rewinded motor felt slightly hotter than the original one, between 45 - 50 degree c. Not sure if this is normal.
Anyway, a great experience for me in learning how motor works, and a satisfaction feeling when a dead motor spins to life!
20170224 added:
To remove the stator, I used 2 flat screw drivers to gently turn back and forth to lift up the stator, as shown in the pic below. Note that using this method, the original winding wires will definitely get damage, its okay if you are going to replace the rewind with new wires. I also found it easier for the stator to get loose if you take out the 2 ball bearings 1st, and also heat the bottom of the motor bell slightly using a hair drier or hot air gun.
20170311 added-1:
I re-rewind the MT2204 using 0.41mm wire, single thread, 12 turns, able to obtain the below result. So better than the stock with a slightly more amp usage. Also it is not hotter than the stock when feel by hand after the thrust test.
625g, 22.8A, 6045, 3S, 0.41mm 12turns
I also found using thicker wire and single thread is easier to wind than smaller multi-thread wire. So going forward I will use this 0.41mm wire for my rewinding.
Below is a comparison of the MT2204 stock 0.1mm and the 0.41 I used this time.
20170311 added-2:
Recently I broke a King Kong 2205 2300kv motor, the motor bell came off and some winding wires were cut.
So is time to do rewinding. I am getting quite efficient on this, took just over an hour to complete end to end. The stock KK2205 uses I believe is 0.1mm, 4 threads, 12-13 turns.
Same as my MT2204 rewind, I also use 0.41mm 12turns for the KK rewind
The rewinded KK2205 thrust test result is almost the same as the rewinded MT2204 but at much lower amp usage.
621g, 17.2A, 3S, 0.41mm 12turns
The stock KK2205 result is:
630g, 17.3A, 3S, kk2205 stock
So the rewinded KK is almost the same as the stock using thicker wire.
Anyway, a great experience for me in learning how motor works, and a satisfaction feeling when a dead motor spins to life!
20170224 added:
To remove the stator, I used 2 flat screw drivers to gently turn back and forth to lift up the stator, as shown in the pic below. Note that using this method, the original winding wires will definitely get damage, its okay if you are going to replace the rewind with new wires. I also found it easier for the stator to get loose if you take out the 2 ball bearings 1st, and also heat the bottom of the motor bell slightly using a hair drier or hot air gun.
20170311 added-1:
I re-rewind the MT2204 using 0.41mm wire, single thread, 12 turns, able to obtain the below result. So better than the stock with a slightly more amp usage. Also it is not hotter than the stock when feel by hand after the thrust test.
625g, 22.8A, 6045, 3S, 0.41mm 12turns
I also found using thicker wire and single thread is easier to wind than smaller multi-thread wire. So going forward I will use this 0.41mm wire for my rewinding.
Below is a comparison of the MT2204 stock 0.1mm and the 0.41 I used this time.
20170311 added-2:
Recently I broke a King Kong 2205 2300kv motor, the motor bell came off and some winding wires were cut.
So is time to do rewinding. I am getting quite efficient on this, took just over an hour to complete end to end. The stock KK2205 uses I believe is 0.1mm, 4 threads, 12-13 turns.
The rewinded KK2205 thrust test result is almost the same as the rewinded MT2204 but at much lower amp usage.
621g, 17.2A, 3S, 0.41mm 12turns
The stock KK2205 result is:
630g, 17.3A, 3S, kk2205 stock
So the rewinded KK is almost the same as the stock using thicker wire.
Hi
ReplyDeleteI have a question, 12 turns as compared to 17 will change kv.
How the fc will balance a different kv motor on a quad
Also how you removed the stator
as this was kind of exercise for me to learn motor rewinding, so far i have rewinded 2 MT2204, have not put them into a quad yet. you are right, the kv has changed, so can not mix it with the original motors. I planned to rewind 4 in total so i can put all 4 into a quad, the current 12 turns is not my final 'design', i intended to try 14 turns as i think i can put in 2 more if I do it properly. I also want to try with a thicker wires, eg 0.4mm or 0.5mm, thus will use 1 threat instead of 2x, to see if the thrust can be improved and also less heat.
ReplyDeleteto remove the stator, i used 2 flat screw drivers, see my new update with a picture above. cheers.
Changing count of turns or wire thickness will change KV.
ReplyDeleteThicker wire gives more Amps, more amps equals more KV.
Less turns will cause more amps too. More turns gives more torque.
Thanks for the notes, I am about to try a thicker wire, 0.4mm single threat, will report the thrust and max amps.
DeleteMy MT2204 that i've burned had double 0.2mm, 17 turns windings. I've rewound mine with dual 0.22mm. Now i will test if this one will work with other original in the same quadcopter.
DeleteI just re-rewind using 0.41 thicker wire, single thread, 12turns. More thrust, and not hot anymore after the test. See my added notes above.
DeleteMy .22mm 17turn motor works with other original in one copter, and it flies good.
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ReplyDeleteIt's great of this article and keep update. For experienced person it is very helpful and get satisfaction, it's best way to strengthen practical ability. But for the beginner, I suggest the best way is that directly purchase the best motors, highly recommend to read this article about best brushless motor for quadcopter http://www.rcdronegood.com/most-popular-and-best-motor-for-fpv-racing-quadcopter/
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ReplyDeleteHow about main wire replacing without motor disassembling? I wish to use restore the original wire length in some of my Emax RS2205 and RCX2206 which was used with ESC-s mounted on arms and so motor wires was shortened to 1.5 cm. Can I simply cut out the heat tubes on base of motors to resolder shortened wires to longer wires in same diameter?
ReplyDeleteSorry about deletes. Registering in this thread to get notified on replies is a bit awkward.
yes, you certainly can so long there is long enough wire left after you cut out the heat tubes on the base and cut out the old shortened wires. or alternative, just extend the existing shortened wires by soldering a piece of extra wire to the end then apply heat tubes to cover the solder joint. cheers.
DeleteMine idea was to move ESC-s below arms since I already had three of them bashed with bent and broken props on crashes in various quads. One ESC died in result too. Motors to ESCs on arms was soldered with very short wires. Connection to ESCs at bottom of arm required at least twice longer wires. I cut out heat tubes, unsoldered short wires from motors, soldered longer wires remained from Emax 2306 wire shortening and isolated with a new heat tubes. Those wire pieces have same AWG20 diameter as original Emax RS2205 wires, equal size and length is exactly what is needed. By the way a good example of recycling :)
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