Muller Dynamo

[powercat]

The first picture shows  a close-up of sum magnets on the top side.
The second picture is of the underside, sorry it's the best one I could find.

[k4zep]

@ Woopy . Brilliant bobbins . where did you buy your cores please?


in germany at "conrad electronic"  part n0   501 633

hope this helps

laurent

Go to any sewing center that  your wife likes to go to for fabric and thread, cloth you will find all kinds of sewing bobbins, I have used them for many projects.

Ben K4ZEP

[bourne]

Seeing as though Neptune & Nul-points have separately mentioned my recent video, I will post it here for you to see.

The effect I am seeing is 'Presessional'

Each rotor magnet forms a segment of the circle, for each segment rotated CW you get 8 'events' on all the coils in sequence CCW.

So for each full rotation of the rotor, lets assume it has 8 magnets, you get 8x8=64 magnet/coil interactions each creating an overlapping weave of pos/neg peaks opposite to the direction of travel.

http://youtu.be/Gw652NrIFM4

I also know some of the things I say in the video are WRONG, part 2 will correct it and more

[starcruiser]

from what I saw in the prior video it was a standard radial bearing (skate board), IMO those would be best used with the rig on its side since the bearings used are not designed for that type of load, you would require thrust bearings to have it work long term as it sits. This orientation will provide additional drag/friction.

I use both types in my RC helicopters, typical RPM 3000 on the main rotor and 12k rpm on the tail and I use ceramics too, ABEC 3 or better. I go through bearings and can tell you they will not stand up well as shown. Build it as is but expect the bearings to get notchy and bind after awhile.

I would get some good skate board bearings to start, they are cheap enough

[DadHav]

John,  thanks for that info and link.  Can you provide links to any other favorite motor sources or do you think HobbyCity is best?  Do you have links to something like that $10 servo tester and maybe the 20 amp speed controller for around $10?  Thanks again for your help here!

Hello.  I didn't look to far but just tagged a couple items on HK. I'm in no way recommending these exact parts but they are typical of the inexpensive choices. You can spend 10 times the price for guaranteed quality motors and drivers. I gotta ask this. Do you really want the excess baggage of the electronics just to have a motor for testing alignment and tuning? There should be some really good surplus DC motors as well.
You know if you do a search for servo driver circuits, you will find some simple 555 timer circuits you can build yourself.

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10531
Servo Tester

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=2164
Typical Speed Control

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=8487
Typical inexpensive outrunner.

John H