"Mr Macaw" wrote in message news
On Sun, 08 May 2016 23:03:48 +0100, Fredxxx wrote:

On 08/05/2016 15:23, Mr Macaw wrote:
My jigsaw started sparking and throwing out smoke, so I took it to bits,
found a shorted coil in the motor, and disconnected it. But it's still
doing this (sew video). Is there anything that can be done, or does it
go in the bucket?

https://www.dropbox.com/s/75z1zyve3jajgg7/Saw.AVI?dl=0

Consider the armature approximating a rotating transformer.

One segment that has a short is like shorting a winding in a transformer.

Either get a new armature, or get a new jigsaw. I would favour the
latter.

Couldn't I short a winding 180 degrees round from the already shorted one?

You could, but you'd still get that arcing.