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Old Nov 03, 2014, 01:42 AM
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manuel v's Avatar
Mexico, BC, Mexicali
Joined Aug 2004
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Rewind DJI E300 2212-920

In my last test. Stock motor.

Motor DJI 2212-920
No load. .33A, 11.20V, 9,800 rpm 875 Kv.

Iflight 9.4x4.3 CF 8mm CCW. 6.40A, 11V, 8000 rpm, 70.4 watts.

DJi stock plastic propeller CCW. 6.50A, 11V, 8000 rpm, 71.5 Watts.

First disassemble the motor, removing the clip, a washer and then the bell.
Try to remove the bearings, but they are too tight, so I gave up doing to avoid damage.
We install an X in the base and is mounted on a piece of wood.
To get started I put the tube penetrating bearings WD-40 and put it overnight in the freezer.
The next day try to remove it with tweezers and a piece of leather.
But it was very hard to reach it away, and discovered that the stator is attached with some epoxy.
Unroll the wire. 3 Thin wires to 14 turns and about 74 inches in length.
The TC7 tells me that the ideal size for that stator is 25AWG.
So to do the same Kv, 14 turns and has used the new technology proves DJI 2 layers of a single wire, which will be of 25AWG.
With termination Delta.
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Last edited by manuel v; Nov 04, 2014 at 01:30 PM.
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Old Nov 03, 2014, 01:45 AM
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Motor 1. 14turns, DLRK, Delta. 25 AWG wire.

No load test.

.32A, 11.8V, 10,500rpm, 889 Kv.

I flight 94x43 8mm CF CCW. 6.77A, 11.08V, 8300rpm, 75.01 Watts.
DJI stock plastic 94*43 CCW. 6.83A, 11.03V, 8300rpm, 75.33 Watts.

Test with other DJI propellers. all 9.4x4.3

Prop no. 1 DJi CCW 6.83A, 11.03V, 8300rpm, 75.33 Watts. 752.49 Kv.
Prop no. 2 DJi CCW 7.42A, 10.96V, 8100rpm, 81.32 Watts. 739.05 Kv.
Prop no. 3 DJi CW 8.53A, 11.55V, 8200rpm, 98.52 Watts. 709.55 Kv.
Prop no. 4 DJi CW 8.67A, 11.47V, 8100rpm, 99.44 Watts. 706.19 Kv.
Prop no. 5 DJi CW 8.70A, 11.46V, 8100rpm, 99.7 Watts. 706.8 Kv. NEW.
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Last edited by manuel v; Nov 04, 2014 at 01:31 PM.
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Old Nov 03, 2014, 01:57 AM
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Mexico, BC, Mexicali
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75 watts is too low for this motor.
But I want to use 4slipo, so I will increase the Kv slightly.
This has used 13 turns of 25 gauge.
Will be easier to do and hopefully good results.
According TC7, will be 957 Kv.
With wire 70 inches long

Prepare the motor in the same way as above, but now first heat the base with a heat gun and the tongs and leather of a belt off the stator.
Stator comes off very well, but it does not, so I put WD-40 and the refrigerator after an hour take it off easily.
Still staying slightly damaged green epoxy, then I put a regular epoxy.
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Old Nov 03, 2014, 06:35 PM
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Mexico, BC, Mexicali
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Motor no. 2 ready.
13 turn, DLRK, Delta, 25 AWG wire.

No load test.
.38A, 12.54V, 12,100rpm, 964 Kv.

I flight 94x43 8mm CF CCW. 9.27A, 11.95V, 9300rpm, 110.7 Watts.
I flight 94x43 8mm CF CCW. 8.24A, 10.94V, 8700rpm, 90 Watts.

Prop no. 1 DJi CCW 9.74A, 11.94V, 9300rpm, 116.29 Watts.
Prop no. 1 DJi CCW 8.51A, 10.92V, 8650rpm, 92.9 Watts.
Prop no. 2 DJi CCW 8.88A, 10.79V, 8400rpm, 95.81 Watts.

Now I'm going to rewind the other motors same.
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Last edited by manuel v; Nov 04, 2014 at 01:37 PM.
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Old Nov 03, 2014, 10:43 PM
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I decided to torture my newly wound motor no.1.
Since I will not use at that Kv.

So I started by putting a thermocouple at the base and a carbon fiber propeller 9.4x4.3

All tests were around 30 seconds fast.
noting Watts, initial temperature, temperature at the end of the 30sec. and maximum temperature reached by turning off the accelerator.

3s. 94Watts, 7.7A, 77.4F, 83.8F, 95.2F/35.1C.
4s 152Watts, 10.37A, 79.7F, 87.8F, 101.8F/38.8C.
5s 240Watts, 14A, 77.2F, 90.2F, 134.1F/56.7C.
6s 445Watts, 19.3A, 83.3F, 108F, 167F/75C

A 6slipo, the motor may burn out very quickly, I do not know if running it at low percentages of throttle, the motor endurance. if so, there's no point putting 6slipo. better to deal with 5slipo.

A5s lipo, the motor overheats even though the voltage is too low for 5slipo.
possibly occupy the throttle handle.

A 4 and 3slipo the motor works well and can be used 100% throttle for long.

Consider that this motor is rewound with thicker wire and a far superior to any motor manufactures packaging.

Possibly the original motor to warm faster than this.
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Last edited by manuel v; Nov 04, 2014 at 12:49 AM.
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Old Nov 06, 2014, 12:00 AM
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Motor 3 ready.

No load test.
.35A, 11.71V, 11,150rpm, 952 Kv.

I flight 94x43 8mm CF CW. 8.88A, 11.30V, 8,800rpm, 100.3 Watts.
I flight 94x43 8mm CF CW. 8.16A, 10.85V, 8600rpm, 88.5 Watts.
I flight 94x43 8mm CF CW. 13.2A, 15.07V, 11,000rpm, 198.2 Watts.


Rewinds the three engines, have a covering of epoxy on top and below.
See details in the photos.
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Last edited by manuel v; Nov 06, 2014 at 01:19 AM.
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Old Nov 06, 2014, 01:05 AM
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Continuing heating tests.

Conduct test both motor rewind # 1, 889Kv,
As a Motor Stock.

Use a battery 4slipo
IflightCF and 9.4x4.3 prop.

The Motor stock
Full throttle, and an average of 157 watts, I need 180 seconds to reach peak temperature of 112.6 F.
I remain stabilized there and cut the motor, this rose to 130.5F maximum.
The RPM highs were 10,600.

Motor No. 1 rewind.
Full throttle, and an average of 177 watts, need 240 sec to reach peak temperature of 109.2 F.
I remain stabilized there and cut the motor, this rose to 129.2F maximum.
The RPM highs were 10,900.

Testing with the stock motor was not the same level of battery charge, being equal, this would have warmed more and faster.
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Old Nov 10, 2014, 04:16 PM
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Mexico, BC, Mexicali
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4 rewinds motors.

13 turns 25AWG.

Motor 1. CW
No Load, .38A, 12.54V, 12,100rpm, 964 Kv.
I Flight CF 9.4x4.3. 8.24A, 10.94V, 8700rpm. 90W.

Motor 2. CCW
No Load, .35A, 11.71V, 11,150rpm, 952 Kv.
I Flight CF 9.4x4.3. 8.80A, 11.30V, 8800rpm. 99.4W.

Motor 3. CW
No Load, .35A, 12.26V, 11.400rpm, 930 Kv.
I Flight CF 9.4x4.3. 8.04A, 11.40V, 8800rpm. 91.6W.

Motor 4. CCW
No Load, .33A, 11.67V, 11,100rpm, 951 Kv.
I Flight CF 9.4x4.3. 8.95A, 11.58V, 9000rpm. 103.6W.
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Last edited by manuel v; Nov 10, 2014 at 04:32 PM.
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Old Nov 10, 2014, 06:12 PM
Condescending Pedant
Joined Aug 2013
985 Posts
It looks like the CW and CCW props are not quite matched. About 10 watts difference. The battery voltage is different on each one as well as the Kv so it's hard to tell exactly. Looks like you knitted some nice motors though.
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Old Nov 10, 2014, 08:27 PM
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Mexico, BC, Mexicali
Joined Aug 2004
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Mike.

The propellers of the same brand and CF are very similar in load.
and test with the same motor and the same voltage.

My main deviation is that the tachometer measures only 100 to 100.

Original 14t for 889Kv.
Know to 13 turn is around 950.
The last motor (No. 3) was more difficult to wind, possibly in 4 teeth I put 14 turns.
So the Kv is different.
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Old Nov 15, 2014, 01:35 AM View Post
qodobansha
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Old Nov 15, 2014, 02:07 AM
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Quote:
Originally Posted by qodobansha View Post
Prepare the motor in the same way as above, but now first heat the base with a heat gun and the tongs and leather of a belt off the stator.

Prepare the motor in the same way as above,
First disassemble the motor, removing the clip, a washer and then the bell.
Try to remove the bearings, but they are too tight, so I gave up doing to avoid damage.
We install an X in the base and is mounted on a piece of wood.

but now first heat the base with a heat gun
and the tongs
(Tenazas, pliers, alicates)
and leather of a belt off the stator.

With Leather, Old belt, leather encloses the stator and and remove it by turning
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Old Nov 17, 2014, 09:55 AM
homo ludens modellisticus
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Quote:
Originally Posted by qodobansha View Post
Prepare the motor in the same way as above, but now first heat the base with a heat gun and the tongs and leather of a belt off the stator.[IMG]http://goo.gl/R6YO3q[/ IMG]
Don't bother Manuel, it's dot-image spam. You hardly notice the dot in the message.

Vriendelijke groeten Ron
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