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kalee20 · 27th Aug 2019, 10:19 pm

Exactly as Mike Cobaltblue says - the turns needed is set by the inductance needed for the frequencies that the thing has to handle (so 5,000 turns and 15,000 turns rather than 12 turns and 36 turns).

I saw the photos and thought, what a horrid-looking transformer! But they do tend to work a bit better than you'd expect. Take care of the laminations, they will be high-permeability material which you really need.

One good bit of luck - the transformer does not have to pass DC current (some intervalve transformers do), else there would be other complications such as non-interleaved laminations and a small air gap.

Handling this sort of wire is not for the faint-hearted. You need a steady rate of rotation and a tensioner, else any jerk will snap the wire. You really don't want to handle the wire - it's probably failed because the original winder had sweaty hands, or maybe wound it after eating their lunch which finished up with a raw orange, and contamination has caused corrosion over the years.

All the same, it is do-able (I have wound intervalve transformers). But expect to spend a few hours at it.

27th Aug 2019, 10:19 pm	#21
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,088	Re: Interstage Audio coupling transformer Exactly as Mike Cobaltblue says - the turns needed is set by the inductance needed for the frequencies that the thing has to handle (so 5,000 turns and 15,000 turns rather than 12 turns and 36 turns). I saw the photos and thought, what a horrid-looking transformer! But they do tend to work a bit better than you'd expect. Take care of the laminations, they will be high-permeability material which you really need. One good bit of luck - the transformer does not have to pass DC current (some intervalve transformers do), else there would be other complications such as non-interleaved laminations and a small air gap. Handling this sort of wire is not for the faint-hearted. You need a steady rate of rotation and a tensioner, else any jerk will snap the wire. You really don't want to handle the wire - it's probably failed because the original winder had sweaty hands, or maybe wound it after eating their lunch which finished up with a raw orange, and contamination has caused corrosion over the years. All the same, it is do-able (I have wound intervalve transformers). But expect to spend a few hours at it.