Motor testing and rewinding info

C

Crash

Defies Psychics
I was flying my beater quad yesterday and it took off on me. The right rear motor just decided to speed up and it was all I could do to keep it in the yard. Then at about 8 feet it dropped into a bush and released the magic smoke.

The windings on the ultra cheapo cf2822 motor burnt. Then I tested a motor with a bent shaft that maybe had 20 minutes of flight time. The windings on that one were shorted to the stator. That motor was an accident waiting to happen.

I never checked them when I bought them. In the future I'm going to pull the rotor off and check all new motors out. Maybe I'll even swap bearings and rewind them. 9 spools of magnet wire are already on the way. ;)

Below are some of the better links I have found. Anyone have any more?

Dry testing motors - http://www.wattflyer.com/forums/showthread.php?t=35216
Motor links and tips - http://www.rcgroups.com/forums/showthread.php?t=240993
Rewind video - http://www.utahflyers.org/build-mainmenu-33/26-planes/25-motor-winding-1
DLRK for dummies - http://www.rcgroups.com/forums/showthread.php?t=736580
More motor education: http://www.rcgroups.com/forums/showthread.php?t=666877
 

B

Buzzed

Member
They make it look easy Crash but I'm betting that's an illusion. Hmmmm I do have an old 2827-35 Roxxy. Can I ask where you found that magnet wire?
 

C

Crash

Defies Psychics
Buzzed said:
They make it look easy Crash but I'm betting that's an illusion. Hmmmm I do have an old 2827-35 Roxxy. Can I ask where you found that magnet wire?
Click to expand...

I haven't done a complete one yet but I can tell it requires attention to detail and patience. If done properly, 'they' say that the motor will perform better. Looking at the two crap motors that I just unwound I would say that it's a good bet.

I bought the wire from http://www.gobrushless.com/shop/

BTW, I bought 3 different colors because I saw the president speaking today and it reminded me of a rainbow. :rolleyes:
 

R

RTRyder

Merlin of Multirotors
With the price of motors these days I don't see much point in rewinding and swapping beaings on low buck versions. My solution is to just stop buying from sources that I know have really crap motors. The only time I use really low buck motors these days is on my little KK aerobats, I buy a set plus spares cause I know they usually aren't going to survive enough crashes to wear out.

I will say I was really bummed out when I did a spectacular OOPS and destroyed three Hyperion motors in the same crash a couple months ago. I bought them as closeout specials when that model was discontinued and beat the living H**l out of them for over a year before doing enough damage to put them beyond repair. Kind of hard to rewind them when the base is bent in two different directions with the threads ripped out of the mounting holes, the shaft has a 30 degree kink in it, and the rotor has been smashed down onto the windings! That's when I decided that any quad that gets routinely dropped in the dirt would only get motors costing $15 or less, losing $100 worth of motors in one crash hurts :mad:

I replaced the Hyperions with Exceed Alpha series and have been surprised at the abuse they'll take, they even come with spare shafts and decent prop adpators, they're now my low $ motor of choice for beater quads. For the amount of time it would take to rewind or replace a bearing on one I'd rather quickly bolt on a new one that costs around $12 and go fly some more.

Ken
 

matwelli

matwelli

Member
Winding motors is fun, i get a kick out of it.
Even cheap motors can be made better (you can do a better job than some one who does it 8 hrs a day on minimum wage)

If you need any advice, hit me up, i have wound a few, from 800 kv to 3500 kv, from $10 turnigys to $65 microdans (the best value motor in the world IMHO)

helpfull hint - single strand winds look cool, but multiple strands works as well and are easier to wind
Get yourself a plastic scraper/spatula/broken prop blade to use to squeeze the winds in to make space
 

matwelli

matwelli

Member
Tricopter motors

4_4d64bb646b2f2.jpg
 

C

Crash

Defies Psychics
Mat, many people suggest the newbie wire. Is that what you used?

How did you strip the insulation so cleanly?
 

matwelli

matwelli

Member
those motors are using twin strand 26 gauge newbie wire (because i had a bunch from some GBx kits) , and its the best for a first timer as the insulation is tough.

Stripping the ends is the painfull part, takes up time and patience, its done using a knife blade and just scrape it off.

Aparently you can use heat and an asprin t disolve the insulation, but i have never tried
 

B

Buzzed

Member
Today I removed the stator from a shorted Roxxy 2827-35 and the windings appear to have been enameled or epoxied to the stator. Is this normal, can the stator be reused or do you all just start with a new stator?
 

C

Crash

Defies Psychics
Buzzed said:
Today I removed the stator from a shorted Roxxy 2827-35 and the windings appear to have been enameled or epoxied to the stator. Is this normal, can the stator be reused or do you all just start with a new stator?
Click to expand...

Read that last link in my first post. I believe Alex uses paint thinner and/or heat. Maybe someone has a better idea though. If the insulation comes off the stator you will have to re-insulate it of course.
 

matwelli

matwelli

Member
I have also heard of acetone working in some instances, make sure you remove the bearings, or at least remember to re-lube em afterwards

I have had one motor like that, managed to use a small file and remove it, a real pain
 


matwelli

matwelli

Member
Dont know that motor intimately...... its 1050 kv, 20 turn ?

14 mag 12 stator, needs to be wound DLRK

To get the kv lower will need more winds , = lower power handling

tell me is it wound star or delta ? if its delta, swapping to star will drop the kv to about 600
adding two more turns (over 20) will drop the kv to about 950

anywho, tell me if its star or delta, and confirm the kv nd number of winds, and lets go from there
 

P

Pip

Member
matwelli said:
Dont know that motor intimately...... its 1050 kv, 20 turn ?

14 mag 12 stator, needs to be wound DLRK

To get the kv lower will need more winds , = lower power handling

tell me is it wound star or delta ? if its delta, swapping to star will drop the kv to about 600
adding two more turns (over 20) will drop the kv to about 950

anywho, tell me if its star or delta, and confirm the kv nd number of winds, and lets go from there
Click to expand...

It was originally wound 12 turn Delta and 924kv.

Star sounds good for a low kv.

Thank you for your help.
 

matwelli

matwelli

Member
Try a 9 turn star then, either with thicker wire (you want to get as much copper in as you can) or two thinner strands.

9 turn star will get you down in the mid 700's

i wouldnt go much slower, the Lotus T580 at 600 kv is a bad compromise, super efficient but hard to control in a breeze
 

P

Pip

Member
matwelli said:
Try a 9 turn star then, either with thicker wire (you want to get as much copper in as you can) or two thinner strands.

9 turn star will get you down in the mid 700's
Click to expand...
Okey doke, thank you again Matwelli.

I'll see if I can find a winding pattern to use on the stator for a star then on the net (I'm new to this kind of low level winding).
 

matwelli

matwelli

Member
i would be more helpfull, but i am time starved tonite - go to (shock horror) rc groups and search for DLRK winding tutorial

star and delta are wound the same, only diference is how you terminate it.

If you get stuck, i will dig up some info tomorrow
 

C

Crash

Defies Psychics
matwelli said:
i would be more helpfull, but i am time starved tonite - go to (shock horror) rc groups and search for DLRK winding tutorial

star and delta are wound the same, only diference is how you terminate it.

If you get stuck, i will dig up some info tomorrow
Click to expand...

The DLRK winding tutorial is the second to last link I posted in the first post. On that same thread is a delta and star wind method with great description and pictures.
 



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