Re: Wimshurst machines (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 14 Nov 2003 22:11:44 -0200
From: Antonio Carlos M. de Queiroz <acmq@xxxxxxxxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Wimshurst machines (fwd)

High Voltage list wrote:

> From: Finn Hammer <f-h@xxxx>

> I use very soft and thin wire for the brushes too. But it annoys me if
> these wires drag marks around the disk, by touching the disk itself, so
> i had holes drilled in the narrow end of the sectors, threaded them, and
> put small screws in them, so that the brushes touch them, not the disk.
> It is just another way of making the small bump that is often made on
> sectors, if they are made from foil, and glued or waxed on to the disks.

Now I understand, and also the problem with sparking between the disks
caused by the screws. You can prevent the sparking by fixing disks of
thick adhesive vinil foil over the holes, at the internal side. Two
layers to be sure. I like to make brushes with thin nickel-chrome wire.
They don't leave residues. I am now trying to wrap these wires around
silk threads, fixing with some glue. The wires resist much more time
in this way.
I have made sectors with bumps using aluminum plate. Much more difficult
than with thin foil, but works. Long bumps also guarantee contact with
the neutralizer brushes. Buttons tend to drive them to the sides.

> I have a picture of one spare disk here, without screws, but with holes.
>
> http://home5.inet.tele.dk/f-hammer/wimshurstdisk.jpg
> Battery in the center is a AA for size.

Nice. You could try to remove the labels from the disks.

Antonio Carlos M. de Queiroz