current limiting using microwaves
From: Alan Sharp [SMTP:100624.504-at-compuserve-dot-com]
Sent: Sunday, February 15, 1998 3:01 PM
Subject: current limiting using microwaves
As I mentioned before
>> 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
>> just under five amps (12" arcs) to over 10A (32" arcs - limited by the
>> in the garage).
Malcolm pointed out that:
>The loose inductance is resonating with the
>transformed primary cap value as seen at the primary of the
>transformer. A consequence of this is that the secondary of your
>transformer will go to a far higher voltage than SQRT(2) x 5500V if
>your gaps allow it.
I removed the micrwave transformer that was in series with the 5500v
transformer output giving 5500v + 2000v, leaving me the 5500v transformer
with 2 microwaves and the variac in series on the mains side as before.
I got even more output.
I'm not sure how far I can push this though - I don't want the 5500v
Alan Sharp (UK)
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