Looking at Jenning's data on Vacuum Variable capacitors I noticed that
the
voltage rating on the capacitor is the Test Voltage and the working voltage
is less.
For example a 3000volt cap Cxxx-300-3 has a test peak voltage rating of
3Kv and a working peak voltage rating
of 1.8KV. A 5Kv one has working voltage of 3KV and a 7.5 has working peak
voltage of 5KV.
So if I am running a 4-1000A with 5K plate resistance and 1500 watts out
the RMS Plate voltage would be 2740 Vrms or 3872V peak. I can't use a
3000V cap based on those
figures but must use at least a 7.5KV cap.
So what gives. I expect most of us are pushing these caps beyond their
working voltage limits.
73
Bill wa4lav
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