[Elecraft] KPA500 Proper Transformer Tap setting

[Harry Yingst via Elecraft]

My line voltage is 239 (which calls for the yellow tap)  but on Key down it sags to 59v
With the Red Tap it only sags to about 66v (80.7 no key)

So The proper tap would be?







      From: Jack Brindle <jackbrindle at me.com>
 To: Harry Yingst <hlyingst at yahoo.com> 
Cc: Elecraft Reflector <elecraft at mailman.qth.net> 
 Sent: Sunday, March 22, 2015 3:58 PM
 Subject: Re: [Elecraft] KPA500 Proper Transformer Tap setting
   
Both. The HV is directly proportional to the line voltage. This makes sense, since the HV is derived through a linear transformer.
If your line voltage rises so that it causes the HV to go too high (spec is 85, the KPA faults at 90V), then you have set the tap incorrectly.
Set the tap according to your line voltage as described on page 9 so that it gives you nominal HV in the range as described on page 17.

- Jack Brindle, W6FB
Elecraft Engineering




> On Mar 22, 2015, at 11:49 AM, Harry Yingst via Elecraft <elecraft at mailman.qth.net> wrote:
> 
> In the manual on page 9 it shows to set the tap for the line voltage, but on Page 17 under Note it states
> "The KPA500 operates to full specifications when the HV under full load isbetween 60V and 85V as shown on the LCD (Tap HV to display the voltageunder CW “key down” conditions at full power). The maximum voltage is setusing transformer taps as described on pg. 9."
> Which is correct?
> 
> 
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