[Amps] Updated amp pictures

Bill Turner dezrat1242 at yahoo.com
Thu May 30 01:07:51 EDT 2013


ORIGINAL MESSAGE:          (may be snipped)

On Wed, 29 May 2013 18:53:40 -0700, you wrote:

>
>1) I measured the air gap of the capacitor with a feeler gauge and it is about 0.012". If 
>air breaks down at 30 kV/inch, then it is good for only 360V. 1500W at a 1:1 SWR is about 
>273V into 50 ohms.

REPLY:

Remember, arcing happens at the peak voltage, not the RMS voltage. 1500
watts RMS into 50 ohms is 274 VRMS, but 387 volts peak. Your capacitor is
doomed.  

And yes, I'm sure the plate choke was not damaged by heat. I have an
oversized blower (91 CFM) and I monitor the exhaust temperature and it never
exceeds 145 degrees F, even with 100% duty cycle RTTY. Well within the
enamel ratings. 

73, Bill W6WRT


More information about the Amps mailing list