Muller Dynamo

[CLaNZeR]

Was calculating the windings and if using a accurate winding machine with tight tolerences, I came up with the following:

10mm / 0.875mm = aprox 11.42 turns

So 300/11.42 = 26.62 layers

26.62 layers * 0.875 = 23.29 mm

Now add the 6mm ferrite.

Yet Romero coils look about 20mm and they were hand wound?

Did romero ever post the resistance of those coils? be interesting to compare when I have wound one, before doing all 18 of them.

Cheers

Sean.

[Cherryman]

@ Clanzer

Hi, Not sure if you noticed, but Rom used a 25cm disc. I noticed your drawing has 20cm. 

Sorry, diameter is 25cm and distance from the rotor to the coils is about 3.5-4mm.

[erikbuch]

I think it was 4.86 ohm pr coil.
Best regards
Erik

[Staffman]

@ Clanzer

I think he said it was close to 2 Ohms (between 1.5 and 2), although I can't find the post. If I remember correctly, he said that each coil was different because they were hand wound with twisted litz. His wire (7 x 0.125) would be closer to 0.375 diameter if you bunch the 7 wires together....

Edit... i'm probably wrong about the ohms. Still can't find the post.

[CLaNZeR]

@ Clanzer

Hi, Not sure if you noticed, but Rom used a 25cm disc. I noticed your drawing has 20cm. 

Hi Cherryman

Yep and later then he corrected himself saying:

************
Hi,
I have measured the rotor and it is 20cm, sorry. I had so many changes and I also had a 25cm and a
35 cm rotor in another setup.
************

I spent about 4 hours today reading every post in this thread, before I started to draw up, so hope it is right

Cheers

Sean.