Andrew Gabriel wrote:
In article ,
writes:
PS I'd consider running that off an isolating transformer, with an RCD
AFTER the transformer, not before.
Um, an RCD does absolutely nothing after an isolating transformer...
An RCD before the iso tf will not be effective on the output of the
iso. Placed after the iso TF it will detect earth leakage downstream
if the output's centre tap is earthed, which I did omit to mention.
With this combination, the iso tf means that:
1. a single touching of any live part will result in much less shock
current, since its now 120v not 240.
2. 2 simultaneous touches can access 240v and bite badly, same
as with no iso tf
And the RCD means that:
3. The RCD will trip on first contact, minimising single contact risk
and removing nearly all of the 2 contact risk
4. should an insulation/earthing fault occur, which certainly can
happen on 1920s kit, or any electrical kit, the RCD will act as a
backup protection device.
None of the above will make the thing properly safe, so I cant
recommend using the toaster at all. But if someone does, this will
at least reduce the risks significantly.
Using it as-is direct on the mains isn't something I would
ever recommend. As you go back in history electrical kit does
eventually reach the point of unworkably risky. Converting to LV is
one approach often workable. With a toaster its likely to be
possible to convert it to run on centre tapped 110v provided by a
site transformer. Where original switch contacts are insufficient,
they can be brought out to a relay to control the power - but all
this means significant mods to historic equipment, making it not a
popular option. IRL people using prehistoric electrical kit know
enough to take precautions - but knowledge and precautions do
not eliminate accidents. When all's said and done, I'd just leave
the toaster on the shelf unused.
NT