Wye did I do it?

[ron van sommeren]

... LRK was the original diy winding diagram introduced by Christian Lucas and Ludwich Retzbach in their ElektroModell magazine articles...

Christian Lucas, the 'L' in LRK, earns his money working on 'slightly' larger motor designs at www.magnet-motor.de (English).
Ludwich Retzbach, the 'R' in LRK, an EE too, is a renowned German e-flight author, www.elektromodellflugpraxis.de

Vriendelijke groeten Ron
• brushless motor building tips & tricks • diy brushless motor discussion group • int. electric fly-in, Nijmegen, the Netherlands

[ron van sommeren]

The more I read the more I want to rewind the motor ...

Hook, line and sinker I'm pure evil


Vriendelijke groeten Ron
• brushless motor building tips & tricks • diy brushless motor discussion group • int. electric fly-in, Nijmegen, the Netherlands

[GGoodrum]

Holy crap, that's a big-ass motor! I'm sure Luke is already trying to figure out how he can mount two of these on something...

[Miles]

Holy crap, that's a big-ass motor! I'm sure Luke is already trying to figure out how he can mount two of these.....

[ron van sommeren]

Single strand gives you a better copper fill factor.

Which leads to higher efficiency

Higher efficiency does not only mean that the motor makes better use of the batteries' power, it also means the motor is able to handle a higher power input before hitting its maximum temperature mark i.e. a the power/weight ratio will be higher.

An example:
Say the motor has an efficiency of 70% and it can handle 500Watt input. That means it can get rid off 30%*500=150Watt excess heat. Now, by cramming in thicker wire (and/or using better stator-iron, segmented magnets), efficiency increases to say 75% (I'm a bit optimistic here). The motor's ability to loose those 150Watts has not changed (by radiation, convection and conduction). This means the motor now can handle 600Watt before it hits the 150Watt (25%*600Watt) losses mark. An efficiency increase of 5% gives an increase in the power to weight ratio of 20% (from 500Watt to 600Watt). That's why efficiency plays such an important role, in any motor design: efficiency governs maximum power. The motors weight may have increased a bit due to more copper.

If you increase efficiency of a 80% efficient motor to 90%, specific power would increase by factor 2, i.e. 100%more.

[rkosiorek]

... What is the best way to remove the varnish from the wires? ...

Use real Aspirin. First post, tip #27
http://www.rcgroups.com/forums/showthread.php?t=240993

Vriendelijke groeten Ron
• brushless motor building tips & tricks • diy brushless motor discussion group
• Drive Calculator download & discussion group • int. electric fly-in, Nijmegen, the Netherlands

thanks for the tip ron. tried it toay ant it works great. now i don't need to haul out the propane torch.

i had to re-do the leads on a motor and a big 48V CT. 8A transformer. and i decided to try out the aspirin. i first used up my last 2 pils of name brand stuff. having a few more leads to do i used up some really cheap no-name stuff from a discount store. and it worked even better. less smelly smoke and less residue to clean up.

later i mentioned this to the pharmasist and he was not surprised. according to him the cheap stuff has a higher concentration of the active acid and fewer fillers and buffers.

rick

[dontsendbubbamail]

As I sit here dead in the water with all my controllers blown and waiting for the new stuff to arrive, I decided to take apart my dead HXT 80-85. This one is the newer design that has the large bearing supporting the front of the bell. It was cooked when I blew my last CC controller.

I wanted to try to tease apart the winding leads so that I could practice rewiring it in the wye configuration. Getting the motor apart was not hard. Once you get the large support bearing for the bell off, you are left with the bearing tube assembly and the stator. This seems to be held together with the same glue that was used for the magnets. The good and bad news is that they didn't spare the glue. It was all over the wires and that is no way they could be seperated and rewired as a wye.

Now my thought was that maybe I could rewind the motor. Getting the wire off was not too bad. Except for the fact that some of that glue was holding the wire to the stator and I bent up a couple of the top stator plates while pulling the wire out. I put the stator and bearing tube assembly in the oven and heated it to about 220 F, but could not separate the two. It may not be necessary to separate the two as this design has more space to work with on the motor mount end.

Bubba

[etard]

Hey Bubba, you got any pics of that motor teardown, or at least of the empty parts? I am interested to know this. It seems if the process is not too complicated and parts are easy enough to find, then it would be cool to always have a spare bolt on motor, in case one gets fried. Heck it might be wise to have an extra controller on you ( even a cheap one) the are so light and small. But if your batteries go, might as well call it a day.

[dontsendbubbamail]

Here be the pics.

Bubba

1-motor.jpg (181.01 KiB) Viewed 1081 times

1-magnets.jpg (170.35 KiB) Viewed 1080 times

1-stator2.jpg (118.02 KiB) Viewed 1081 times

1-stator.jpg

(97.08 KiB) Downloaded 515 times

1-winding.jpg (107.15 KiB) Viewed 1078 times

[etard]

Dang, ask and ye shall receive. Thanks man.

Wind it up dog!! That motor could be an opportunity to make it better. I wonder how much a rebuild costs, also wonder if you could try to wind it for a lower KV. Put some nice bearings in there and your back in biznass!

[dontsendbubbamail]

Rewinding is something I would like to do, but my main goal is to get my bike running again. I have two 18 fet Infineon controllers on the way. One will be run stock and be my backup controller. The other will be modded and possibly destroyed, but I will not touch the backup controller. I have a blown 6fet and a 12 fet controllers that I may try to bring back to life with some of the 4110s that I got from Methods. If HobbyKing will ever get more stock, I will also buy an 2 extra motors. One to experiment with and one will stay stock as a backup. I am tired of not being able to ride because I have blown something up. I have lost at least two months or more of riding due to not having replacement parts.

Bubba