Hello all,

I'm currently rewinding a power transformer from an american Knight R/C tester, which it would seem to me suffered lightning damage or something of that nature. The 500v secondary winding is open but one side has a short to the primary which won't do.

With the secondaries being 500v, 60v and 6.3v it makes it a rather unique transformer. It's a rather small device too, only powering a 6X4, 6E5 and capacitor under test.

I'm mid unwind currently, counting the turns, but I've measured the wire diameters and the 60 and 500v windings both appear to be 0.08mm dia wire based on wrapping twenty turns tightly onto a screwdriver shaft and measuring that way.
What is my best way of buying such thin wire in the lengths I need?
The 500v winding is a few thousand turns on it's own.

Whilst I'm going to such efforts I'll wind the primary for 240v, just doubling the amount of turns but also reducing the gauge size.

You may have to convert that wire to gauge to find a source. Only for the 12.6V winding that transformer is similar in voltage to that of a Heathkit IT-22

The wire is normally advertised a "winding wire" / magnet wire. beware of NOS some of the lacquer on that old stuff, can be brittle.

Some years ago my solar power inverter cut out because the local line voltage exceeded the inverter's export voltage limit of 255 volts. Now while this has only happened once (newly installed solar setup elsewhere that had an incorrectly set export limit exceeding 255 volts), the voltage regularly sits at 245 volts and occasionally gets to 250 volts.

I mention this because I wonder weather it is worth your while to wind in some extra taps in the primary.

Oh yes, the term "winding wire" I hadn't searched before and I did find listings from china at least that sell wire sizes of that nature.
Before I was only searching for enameled wire but didn't find anything that small.

I'm going to get 0.08mm / 40awg for the 500v and 60v secondaries. Drop from 0.25 to 0.2mm for the primary and wind for 240v and 0.5mm for the 6.3v.

STC, my plan is to add a NTC varistor inline with the mains anyway to act as a soft start for the filaments, it'll scrape off a few volts even when warm on its own.

That is what I was saying re wire coating. Mate wound a transformer with old enamelled wire and the coating fractured. That may be the reason for some older transformers being bulky as each layer was separated from the winding above & below, with insulation paper.

Most of the new better stuff has a Teflon based coating that will handle more heat.