Can this BLDC motor be repaired?

Started by Swapnil, May 30, 2011, 10:53:04 PM

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Swapnil

Wow, thanks sir! This thread is turning out to be a really informative tutorial.
We'll be eagerly waiting for the test photos and vids.

aditya

Mechanical Engineer

TEJASCOOL007

sundaramvelar sir,
thanks a lot for the information on rewinding...
i too winded my motor with the help of this post...
and special thanks to ANGAD who guided me ....




:salute: :salute: :salute:
struggle is the only key to become airbone..!!!

sundaram

You could have reduced the number of turns per pole by two or three for more even fill. However since you have been able to wind all poles no worries.

TEJASCOOL007

#79
no sir i have kept turns tthe same ie.15 turns
instead i changed the wire used
previously 3 wires bunch was used now a single thick wire as seen in pics
will that do....????
struggle is the only key to become airbone..!!!

sundaram

That what I was implying since you have used a thicker wire you could have reduced the number of turns per pole by two. It would have reduced the crowding and would have a more even winding. Now that you have been able to complete all pole without wire spilling outside the pole shoes no issues.

sundaram

#81
I had tested and recorded video long time back but could not convert it and load it because of some my Codec problems in my laptop. downloaded the latest codec K Lite full version and now I could convert and load it.

For testing the Motor I used a 7 x4 Pusher Prop since I wanted to measure the the thrust also.

I have mounted the Prop pushing the air away and with a digital scale which is tared to be zero with the complete set up, placed on top of it. I am measuring the Thrust approximately by the weight of thrust.

Watch the video please


sundaram

#82
It gave a thrust of around 500 gms on full throttle with a 7 x 4 Pusher Prop consuming less than 15 Amps and less than 150 Watts. Should be able to try with 8x4 on a model for short burst of full throttle runs and bigger props with 2S Lipos

sundaram

Now for an example of ABC winding. I have chosen a really micro 9 pole motor with 12 Magnet.

This was a motor which I bought from ebay, this is a three grams micro brushless. It came damaged in transit with supply wire entwined with shaft and was not freely rotating.

Now I plan to revive it. It had 16 turns per pole. It was 7000 KV 1S motor.

Some photo graphs of dissembled motor. Lucky that my Dell streak is able to take really!! closeup photographs. When rewinding I need to work under magnifying glass for this motor.

SunLikeStar

I'm thinking about rewind my 3536 motor. I've never done anything like this before and looking forward to some DIY fun :) So what kind of wire should i get, what is it called? Any chance of finding it around the block (eg: in repair shops) or will i have to hit the electronics market ???

sundaram

Electronics Bazaar is the right to place ask for enamel insulated Copper Wire. Avoid Enamel insulated Alluminium wires. Any Transformer/ motor rewinding chaps will be having it. What is used for transformer low voltage side windings and for field coil of motors is the right bet. They are available in varying gauges. It would be best to take the sample of wire already wound in your BLDC for obtaining the enamel insulated wire.

SunLikeStar


controlflyer

this is a easy task, if you have the interest, take sample wires to your local electronic shop and tell him to give you the winding roll for that wire diameter. Before you unwind the motor, carefully keep a count of your turns.
It will work!

Regards,

CF.
Money flies when the transmitter is ON...

manojswizera

Hi , Sundram sir thanks for sharing wonderful knowledge with us all. :salute:  Your knowledge encouraged me to again try rewinding my brushless. I trieda 3 times before, following you-tube videos, but no success. I tried your ABC system this time and guess what it worked..   ;D
my brushless is with 6 magnets and 9 poles. RPM was 3100 with factory settings . 
I didnt remember how was the factory winding. But now its rpm has incresed as seen pratically ( no instrument with me to know RPM )
Now it is not moving 8'' prop, making sound, but moves 7''DD prop well. Why so ??? :headscratch:
I wind it with 7 turns with 26 gauge (approx), as beyond 7 were not possible, overcrowded. What i can do to increase torque.
Prior i used 9'' prop before it damaged.   Attaching my brushless pics after winding.
Russ-40 Trainer, Mr.moss, Pushler, Skysurfer, Mugi , F-22, Red swan, Xtra-300, redfury, flying mantaray.

SunLikeStar

You'll have to increase number of turns to increase torque, how many turns did the motor had before?

sundaram

Your is a 6 Magnet, 9 Pole Motor which is basically designed for High KV more than 2500, unlike a 12 magnet 9 Pole Motor which is designed for KV less than 2500.

It is better you use the same 7 turns per pole configuration for full efficiency, with smaller props for a high speed plane.

It is not advisable to use a Larger prop for a high KV motor. I wonder How you were able to use a 9 inch prop earlier for a 3100 KV motor.  :headscratch:

Like what sunlikestar has said if you use more number of turns per pole with thinner gauge wire then your KV will reduce and Torque will increase, but your being a 6 Magnet Motor it is not desirable to reduce KV very much since it is basically designed for High KV.

manojswizera

#91
Sundaram sir, but can u give me a idea, how much amp it is drawing from my lipo. And which Amp ESC will be suitable for it, lipo capacity ? What could be the thrust approx
Russ-40 Trainer, Mr.moss, Pushler, Skysurfer, Mugi , F-22, Red swan, Xtra-300, redfury, flying mantaray.

sundaram

Watt meter is a best choice for it, since Amp drawn and thrust are all dependent on various factors. prop size, pitch of prop, static and dynamic, voltage applied, motor size, length of winding, no of turns per pole, thickness of wire, capacity of ESC used and many more.

SunLikeStar

I've finished winding using this image posted earlier in the thread, now i'm totally confused which ends to join  :banghead: i forgot which end is the starting point :help:  

SunLikeStar

#94
Just finished my motor and its alive now :) Have not measure amp draw and kv yet but its looking good.
I just twisted adjacent wires where you started is not important; got this tip from here a 5:30

pawankhedkar


manojswizera

Can anyone tell me how to download the above video from vimeo.
Russ-40 Trainer, Mr.moss, Pushler, Skysurfer, Mugi , F-22, Red swan, Xtra-300, redfury, flying mantaray.

KALYANPRODHAN

I use downloadhelper plugin in firefox with FDM.
While playing any movie, downloadhelper gives me the option for download.
And if different varient available, I get options which one to download too.
Just try, it's easy.

And if you want to edit or convert, just use K-Lite mega codec pack and TMPGExp Portable.

Thanks
We have to unite and to prove ourself to make indigenous products as well as marketing / Canvasing them. I'm sure we must achieve success if we try unitedly.

SunLikeStar

Quote from: swizera on February 19, 2012, 03:40:31 PM
Can anyone tell me how to download the above video from vimeo.
Try this http://keepvid.com/ fast and simple :thumbsup:

manojswizera

Russ-40 Trainer, Mr.moss, Pushler, Skysurfer, Mugi , F-22, Red swan, Xtra-300, redfury, flying mantaray.