Project Ryu - DIY Field Coil Loudspeaker

Hi Hentai,
thanks for your confirmation of the material.
i 'm planing a 15" driver want to use field coil motor. but i don't know how to use FEMM to simulate. so i have to spend time to learn this thread from beginning first.
basically for the material and the structure of the motor i have two questions:
1. do i need lathe all the parts of field coil motor by the material i linked above? or i just need to lathe the pole piece to reduce the total cost? (the above material is more expensive than SAE1008 or SAE1010 steel)
2. from your design i can see the copper coil sealed in a sae1010 material can. because i need a more powerful motor to drive a 15" cone. maybe the current is over 3A. so is the open frame better for the heat radiation? (the driver will be installed in a bass reflex box). the picture is my thinking.
thanks in advance for your kind help!

Jason
 

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WOW!you have done a great work! It seems a simple work to design a field coil motor. Many thanks for your sharing.
I will use a Altec 416 voice coil with 76.2mm inner diameter. 15" paper cone, the weight of voice coil+cone+cloth foam is about 50g. The reason I choose Altec 416 is that the parts and technical information are very easy to get from the web.
I am in hurry to download your script and FEMM to study. Haha! There must be more questions. I hope that would not disturb you a lot.

Thanks again!
 
Hi Hentai,
i just downloaded your script and FEMM 4.2. after i run the script and input parameters there is a error message. it means there is no default block material. i don't know where i can setup the default block material or has to setup that in script? please see the pictures.
thanks!

Jason
 

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I uploaded drawings for a new motor, F144. It will fit a 31mm voice coil, so this time a smaller voice coil for lower weight and for higher frequency extension.

Will start soon winding the fieldcoil and will update the project with fieldcoil data.

You can get 2D and 3D files at the link below:
https://github.com/Taur-Tech/Project-Ryu---Loudspeaker-Drivers/tree/master/Drivers/F144

Some pics of machined F144 pole pieces. Very exciting!
 

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Absolutely beautiful work, Hentai, as always - really looking forward to seeing your measurements and results. If you don't mind sharing, I'm likewise curious about the sets of holes around the periphery of the casing, and would love to know what they do for your design.

I took a long break from my project, but now that I'm enjoying a couple of weeks of vacation I've gotten back to it. I've made my first voice coils, and as a first try I'm reasonably pleased with them. They're about 8.7 Ohms, weigh 2 grams each and use a treated Thai mulberry paper for the former. I plan to make a few versions this week with different resistances.

My first effort making a cone came off it's mold a couple of days ago as well. It's made from the same treated mulberry paper. This first one pictured below has a few cosmetic defects, but that's okay - I'll improve on each try. I have another form for the whizzer cone, and plan to have a few sets of cones and whizzers with different mulberry and washi papers in the next couple of weeks. The one below is 7 grams and is quite stiff. Hentai - do you think I should be concerned with that weight, or does it seem light enough? The motor I've made is very similar to what you built for Frank.

Next week, I'll try try making cloth and paper surrounds doped with highly thinned butyl rubber.

vc.jpg


cone.jpg
 
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