If the capacitor is a blocker, then you would want it to have enough
nanofarads to make a low value of Xc at the worst case (lowest)
frequency, while not being far past self-resonance into higher XL.
Figuring the highest reactance possible, and the line current through
it, you should have a low RF voltage across it. In that case, then it is
withstanding the B+ voltage for the most part. With plate modulation, it
would of course be higher. Assuming that there are transients,
overshoots when energizing a power supply, and occasional high line
voltage, you would take this value and add some safety factor. Caps
typically have a working voltage rating, and you should be somewhat
under this for long life. I don't think 3 times the HV is necessary. I
concur with Carls suggested 5 or 7.5 kV ceramic caps.
73
John
K5PRO
> Date: Fri, 6 Apr 2012 17:33:05 -0400 (EDT)
> From: mikflathead@aol.com
> Subject: [Amps] Plate blocking cap voltage
> To: amps@contesting.com
> What is the rule of thumb for the plate blocking cap voltage? 2 times high
> voltage, 3 times high voltage? This will be for a 4-1000 for 6 meters. Thanks
> Mike
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|