Does anyone know of a supplier of custom R-core transformers in small quantities?
The fanciest website is http://jamestransformer.com/en_index.html but I don't get replies from an enquiry.
There are dozens on Alibaba, but which one to choose?

 

I can't even connect to the server. Please check the URL

 

http://jamestransformer.com/en/transformer/index.html
Gives me this page:
but it hardly matters if they don't respond to enquiries!

 

Now it works for me too. Maybe some kind time-out problem here. Sorry for the diversion.

Do you know any coil winding companies in your area?

 

Yes - there's plenty - three in one small town, but all just EI and UI bobbins; and I know several toroid manufacturers as well, but the only place I've seen R-cores are in India and China.

 

Have you asked any of them?

In the San Francisco Bay Area there were several transformer companies (30 years ago) who would probably take on a new kind of core.

Micrometals in the Los Angeles are is where I would ask first.
https://www.micrometals.com/ The people who ran the companies in those old days were pretty easy-going creative types. You might give those whom you have not asked if they are interested. Business is tough these days.

Another idea is source the cores yourself and wind your own. How hard can it be?

 

Actually, quite tricky. The core is solid. The bobbin comes in two parts, which are snapped together around the core. The bobbins have a geared edge, and are spun around the core by a gear on the winding machine. Not quite as involved as a toroid-winder, but a specialist machine.

 

understand