Pancake coil winding

Isn't it just the degenerate case of 1 turn per layer?

But the ridiculous aspect ratio (height of turns : width of turns way way bigger than one) will require some sort of bobbin wall.

I don't know much about "conventional computer controlled winding machines" but have run hand-driven Morris coil winders.

Tim.

do they dance with swords?

Cheers Terry

No! More like one layer per turn-- but how do they get it to stay in place?

Best regards, Spehro Pefhany

Thats SWords.

Chewing gum ?:-)

...Jim Thompson

Presumably with a bobbin. If you're seeing examples with no bobbin, then they were wound with a bobbin (or the moral equivalent - call it a coil former, if you like) and then probably varnished or epoxied, IMHO.

Cotton covered and soaked with tacky wax.

They might be using self-bonding wire, with comes with a layer of thermosetting adhesive on top of the enamel; you wind the coil, then run a carefully calculated current through the coil to get it hot enough to set the adhesive,then take it out of the bobbin - the application notes specify the kind of bobbin materials you can get away with and the sort of release agents you have to use on the bobbin so that you can take it out of the bobbin.

Most of the people I've talked with who have built self-supporting coils didn't know about self-bonding wire and used slow-setting epoxy resin. Here's the first useful web-site that I found with a quick google.

-- Bill Sloman, Nijmegen

Jim is ever-reliably out of touch.

-- Bill Sloman, Nijmegen

Thanks, Bill, that's very useful information. I think I see how to do it now.

Best regards, Spehro Pefhany

Coil dope? That or hard wax. Those are the only two I've seen used.

Why not make a PCB with a spiral path?

A type of glue seems to be used; applied to the wire feeding into the coil.

Only if it comes from the bottom of movie theater seats...

How tacky? The wax was more tacky than my dumb jokes...

Not possible.

Currently it is often done with PWB processes (selective plating or etching). Previously (about 60 years ago) it was done with litz wire and glue.

I did it in free air. But then, that was 1/4" copper tubing ;-)

Tim

-- Deep Fryer: A very philosophical monk. Website @

reward"

That's not really winding-- and I'm not sure that PWB is practical for relatively small quantities of coils made with exotic alloys. Best regards, Spehro Pefhany