Current limiting using microwaves.

To: "'Tesla List'" <tesla-at-pupman-dot-com>
Subject: Current limiting using microwaves.
From: Tesla List <tesla-at-stic-dot-net>
Date: Wed, 11 Feb 1998 01:23:31 -0600
Approved: tesla-at-stic-dot-net

----------
From:  Nasalharp-at-aol-dot-com [SMTP:Nasalharp-at-aol-dot-com]
Sent:  Tuesday, February 10, 1998 8:13 AM
To:  tesla-at-pupman-dot-com
Subject:  Current limiting using microwaves.

Greetings

My power supply is a 5500v 350mA ex physics lab transformer -
big no current shunts, connected to ground and then to a 2000v
500mA microwave transformer. Giving me about 7500v at 350mA plus.
Primary capacitor is 0.09uF. Mains is 230v 50 Hz here.

I had been using a 2500w electric convector heater for current limiting.
But I tried instead using the primaries of microwave oven transformers,
with the secondaries shorted out. I now use 2 of these in series with a
110v variac used as a variable inductor. I can now control the current from
just under two amps (12" arcs) to over 10A (32" arcs - limited by the space
in the garage).

To use a variac as a variable inductor just connect to one end of the coil
and to the wiper. They won't do on their own as past a certain point they
tend to saturate and effectively become a dead short.

Curiously when I tried to suppliment these inductors by putting a resistor in 
parallel with them - the coil output dropped - I must have some benevolent
resonance / voltage rise / wierdness happenning through the inductors.

Nice though - more output and control.

Microwaves are current limited but probably at about double the value
you might expect from their power rating.

Have fun,

Alan Sharp (UK)

till I am sure that my mail is working please
contact me at:

100624,504-at-compuserve-dot-com
          and
Nasalharp-at-Aol-dot-com

My web site is at:
http://ourworld-dot-compuserve-dot-com/homepages/AlanSharp