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Mar 11, 2021, 05:47 PM
Sydney- Australia
asanga's Avatar

A2212 10T 1400kv Motor Rewind


I have a burnt A2212 10T 1400kv motor with 14 magnets and 12 poles .
Original winding had 6 stands of 0.2mm wires with 10 turns which gives 1.886mm2 cross sectional area of copper per pole
I have decided to use 0.63mm wire (single strand) and 10 turns of that gives 3.119mm2 cross sectional area of copper per pole (about 40% increase)

The issue is its not easy to get 10 turns with 0.63mm wire.
So if I use LRK winding scheme then I only have to do 6 poles (every other pole) and I can cram in more than 10 turns per pole.

According to the calculation below

Turns | wire length | 2Groupparllel D | 2GroupparallelY/Star | Delta Kv | Star/Y Kv |
10 | 55 | 2800 | 1616.580754 | 1400 | 808
20 | 104 | 1400 | 808.2903769 | 700 | 404

My understanding is LRK winding with Delta termination gives 1.9046 (root 3) Kv of the Star/Y kv

so if I have 10 turns LRK (6 poles winding) I can get 808 x 1.9046 x Root 3 = 808 x1.9046 x 1.732 = 2665 Kv

By increasing the turns to 20 LRK (6 poles winding) I can get 404 x1.9046 x 1.732 = 1332 Kv (close enough )

Am I correct ???
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Mar 11, 2021, 07:00 PM
Sydney- Australia
asanga's Avatar
Quote:
Originally Posted by Ron van Sommeren
Better copy/paste your rewind to a dedicated thread of its own. More people will see it, more help/info
I try to keep this FAQ/tips/tricks sticky thread lean and mean, every now and then I do a cleanup.

Vriendelijke groeten Ron
ok thanks. I just created a new thread.
Mar 11, 2021, 07:12 PM
Jack
jackerbes's Avatar
Don't be afraid to try it though! And giving the rewind it's own thread will be helpful to others, especially those who think the LRK wind is inferior to the dLRK wind. Here is my thread on doing a LRK wind to the DT750 motor:

LRK Wind on DAT-750 - It's a good one! - https://www.rcgroups.com/forums/show...postcount=1409

And when I tested it, I got this result:

GP 10 X 4.5 SF = 5,744 RPM, 11.58V, 10.00A, 116W
full throttle temp rise 74F to 92F in 38 seconds
estimated thrust = 688 grams

And for comparison, the numbers for the stock DAT-750 motor are:

GP 10 x 4.5 SF = 5,338 RPM, 11.02V, 19.12A, 211W
full throttle temp rise 75F to 81F in 15 seconds
estimated thrust = 600 grams

The bottom line was that I could get the same amount of thrust for about half the input power!

Jack
Mar 11, 2021, 08:26 PM
Sydney- Australia
asanga's Avatar
Quote:
Originally Posted by jackerbes
Don't be afraid to try it though! And giving the rewind it's own thread will be helpful to others, especially those who think the LRK wind is inferior to the dLRK wind. Here is my thread on doing a LRK wind to the DT750 motor:

LRK Wind on DAT-750 - It's a good one! - https://www.rcgroups.com/forums/show...postcount=1409

And when I tested it, I got this result:

GP 10 X 4.5 SF = 5,744 RPM, 11.58V, 10.00A, 116W
full throttle temp rise 74F to 92F in 38 seconds
estimated thrust = 688 grams

And for comparison, the numbers for the stock DAT-750 motor are:

GP 10 x 4.5 SF = 5,338 RPM, 11.02V, 19.12A, 211W
full throttle temp rise 75F to 81F in 15 seconds
estimated thrust = 600 grams

The bottom line was that I could get the same amount of thrust for about half the input power!

Jack
Thanks for the link ! I 'll give it a go as its the most simple winding in my opinion and according to your results its more efficient as well! I'll post my results on its own thread
Apr 07, 2021, 04:53 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Thread OP
Removing insulation lacquer/resin.
Use a flame and an ink eraser
www.rcgroups.com/forums/showthread.php?3864839-Help-please&postid=46890875
Thanks Christo, will add it to OP later on.

Vriendelijke groeten Ron
Apr 28, 2021, 09:33 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Thread OP
Examples.
Say you end up with a Kv=2000rpm/volt, but you were shooting for Kv=1000rpm/volt.
Then rewinding it with double the number of winds will give you the 1000rpm/volt you wanted.

Quadrupling the number of winds will quarter Kv, resulting in Kv=500rpm/volt.
Halving the number of winds will double Kv, resulting in Kv=4000rpm/volt.
Quartering the number of winds will quadruple Kv, resulting in Kv=8000rpm/volt


16. Calculating number of winds for desired new Kv.
For a given motor and phase termination (star/delta):
Kv number_winds = constant
This means that Kv must go up as number of winds goes down and vice versa.
In other words, Kv is inversely proportional to number of winds.

Therefore, given two different number of winds for the same motor:
#winds_new Kv_new = #winds_old Kv_old
This gives the number we are looking for:
#winds_new = #winds_old Kv_old / Kv_new
where Kv_old is calculated either from the factory wind or from a quick'n dirty thin wire 10 (20) testwind or from an old wind in combination with the generator-test (further down the road below).

You only have to test-wind one of the three phases. For delta you use the measured voltage as is, for wye you multiply the voltage by √3.

Note that parallel strands/winds count as one wind!

Vriendelijke groeten en wees voorzichtig, Ron
Last edited by Ron van Sommeren; Apr 28, 2021 at 12:32 PM.
Jun 09, 2021, 03:51 AM
Registered User

winding opinion


hello
I need some advice. So my little project is a cooling system, so i need a brushless with low rpm and will be good a little more of torque.
I already buyed a 24 nutes stator outside diamter 61,5mm and 10 mm thick. I watched this gimbal motors with more nutes.
So my question is how much magnets do you advise for low rpm more torque and more important to run silent as a mouse.

thanks for the reply
Jun 09, 2021, 04:37 AM
homo ludens modellisticus
Ron van Sommeren's Avatar
Thread OP
Better copy/paste your project to a dedicated thread of its own Andrej.
More people will see it, more help/info.
I try to keep this FAQ/tips/tricks sticky thread lean and mean, every now and then I do a cleanup.

Vriendelijke groeten Ron
Jun 09, 2021, 06:05 AM
Registered User
thanks for advice, i have creat a new thread

Regards


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