Re: synchronous rotary mechanical bridge rectifier

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
 >
 > Original poster: "robert heidlebaugh by way of Terry Fritz 
<twftesla-at-qwest-dot-net>" <rheidlebaugh-at-desertgate-dot-com>
 >
 > Josh: Years passed I used a mechanical rectifier to charge batteries until
 > the contacts eroded to thin to use.( about 50 years use) The system was
 > simple. a hores-shoe magnet, a coil, and a tuning fork type read contact.
 > The system was tuned to 60 cycles ( no hertz in those days) as the input
 > polerity was negative the contact was open, as the AC polerity was positive
 > the contact was closed sending 30 amps to the B+ and filiment battry banks
 > to run the radio. The charger also charged the Edison-cell lamps to use in
 > the mine. When the contacts wore out I replaced the contact with a diode.
 >      Crude but good    Robert  H

	About 1940 someone gave me a similar charger, made by Benwood.  It
worked great when it worked, but had problems with the contacts
sticking.  The thing still lives after a fashion, as the transformer
from it is in a battery charger I use frequently.

	High voltage mechanical rectifiers were quite common in the early
1920's (and probably before) and used to power electrostatic
precipitators in smoke stacks.  Created hellish radio interference for
the poor people who were trying to listen to rather weak broadcast radio
signals with rather "weak" receivers.  You'll find numerous references
to them (and cursing of them, of course) in the literature of the day.
I suspect a good one would be quite usable for DC TC work, but not worth
the bother.

Ed