We used to use Mica, but the bend radius needs to be quite obtuse. There is
also mylar film that is often used in a tape form, its often yellow, what
colour is it in the video?
Brian

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"jon" wrote in message ...
On Sat, 01 May 2021 19:55:31 +0100, GB wrote:

On 01/05/2021 19:13, AJH wrote:
I had a mishap this week when 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. I 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 section 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?

How hot does this thing get in normal use? I suspect that the guy in
Pakistan is just using ordinary PVC sheeting. However, as we don't know
for sure, why not use some oven liner?

https://www.johnlewis.com/nostik-tef...g-mat/p2925542



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

Sellotape?


However, to avoid potential problems use high temperature tape:

https://www.amazon.co.uk/TOOHUI-Temp...ant-25mmx10mm/
dp/B07MNRJC9S




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



Lots of high temperature paints available.



I gather you have a new starter on order, so this is a temporary stop
gap solution. I'm not sure what the downside is if it fails? Will it
bork the engine, or just put you back to square one?

If the downside risk is small, I'd just use ordinary plastic insulator
and ordinary tape and paint. If you want to be sure it's a good repair,
then spend 20 quid on high temp bits to fix it.

And whichever route you go, you NEED to spend another 20 quid on PPE
before you burn the existing insulation off. Life is cheap on the
sub-continent.

Or even PTFE tape.