On 01/05/2021 19:13, AJH wrote:
I had a mishap this week whenÂ* the main terminal on a tractor starter
motor became loose and rotated allowing it to contact the motor winding
terminal, while the engine was running. IÂ* didn't notice anything until
the damage was done.

As this is an old ford industrial engine the starter is going to take a
while to arrive so I thought I'd see if the old one could be made
functional again.

The armature seems okay, no shorts to the iron core and the commutator
and brushes are serviceable.

One of the 4 stator coils has shorted and burned off its wrappings, the
others seem fine, the copper is so large a cross sectionÂ* it is not
possible to discriminate the resistance as it is so low but the copper
rectangular section looks sound.

Now looking on you tube if anyone has the time to watch some old school
workmanship:

https://www.youtube.com/watch?v=4bFou5VIFzM

at 2 minutes the guy is cutting some insulation sheet, anyone any idea
what it is and if it is avalable?

'insulation sheet'; on old kit would be something like phenolic resin
impregnated paper - a sort of bakelite lookalike - but that looks
alarmingly like simple plastic sheet. Which will melt at high temperatures.

You can buy stuff like that at any model shop.
Oh thinking, I'd use ptfe.

https://www.ebay.co.uk/itm/223216541194

Later at 4:20 he wraps with a tape, any ideas what it is and where I can
get some?

Almost anything would do. Back in the day it might have been cotton or
linen.

I wouldn't use nylon - cotton 'webbing tape' is probably best these days.

https://www.ebay.co.uk/itm/191918411510


At 5:40 a paint is used to cover the wrapped coil, is this likely to be
anything special?


Typically old electric wire was insulated with shellac. French polish to
you.

That looks like 'any old muck'. Its only there to stabilise the tape.

For the authentic Awful Smell on overload, why not use shellac?




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"Socialist governments traditionally do make a financial mess. They
always run out of other people's money. It's quite a characteristic of them"

Margaret Thatcher