[Elecraft] Operating KPA500 on 220V

[Doug Person]

Thanks Ron.  I read the section several times because not having done 
anything like this before made me a little nervous.  I wanted be sure I 
wasn't missing anything.  My two other amps require changing lead 
configurations as well as fuses.  My HV is now 72 volts with the KPA-500 
plugged into a 220v outlet.  So that's just shy of midrange.  I get 
about 550 watts peak output (just makes this value on voice peaks) with 
30 watts of drive.

73, Doug -- K0DXV

On 7/9/2011 12:11 PM, Ron D'Eau Claire wrote:
> That is correct as far as changing between 115 and 220VAC mains goes, but
> there's a little more to it than that. The power supply is not regulated, so
> its output can vary depending upon the actual mains voltage supplied within
> the nominal 115 or 230VAC ranges.
>
> Secondary taps on the power transformer allow you to compensate for normal
> variations in mains input voltages to produce the correct d-c output voltage
> from the supply. The output voltage should be checked and the taps adjusted
> as necessary any time you move the amp to a new mains outlet (or, of course,
> if you switch from a 115 to a 230 VAC mains supply).
>
> This is all described under "Mains Voltage Settings" in the Installation
> section of the manual on pgs 6 and 7 in the Rev B manual. It's immediately
> after the information on installing the fuses and the fuse holder.
>
> The procedure involves only removing the top cover and attaching the tap
> wire to the rectifier board that produces a voltage in the proper range as
> indicated on the KPA500's LCD. The wires use spade connectors that require
> no tools to connect.
>
> Ron AC7AC
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Doug Person
> Sent: Saturday, July 09, 2011 10:46 AM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] Operating KPA500 on 220V
>
> I meant to say change the fuses and reconfigure the fuse block...  I was
> actually reading the manual when I asked that question.  On other
> amplifiers I was required to change internal transformer wiring to setup
> for 220v.  That's what I meant to ask.
>
> So switching the fuses and changing the fuse block is all I need to do.
> No other internal wiring required.
>
> Doug -- K0DXV
>
> On 7/9/2011 9:43 AM, Ron D'Eau Claire wrote:
>> When you change the fuses, you insert the fuse holder so 220 is visible in
> a
>> little window instead of 115. That changes the wiring to the power
>> transformer input for 220 volt mains operation. It's described at the
>> beginning of the Owner's manual.
>>
>> Ron AC7AC
>>
>> -----Original Message-----
>> Am I correct in assuming that in order to run the KPA-500 on 220 volts
>> all that is needed is to change the fuses to the provided 6 amps, wire
>> the correct plug on the power cord and the power supply will adjust
>> accordingly?
>>
>> Thanks,
>>
>> Doug K0DXV
>>
>>
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