http://www.pc5m.net/projects/filament-inrush-protection also Emtron
uses a simular system
Quoting John Lyles <jtml@losalamos.com>:
> In a crude way, the SCR/Triac dimmers for lighting do this.
>
> Collins and later Continental Electronics had their HV and screen
> voltage soft started by a similar AC cycle chopping, using SCRs in the
> primary. This is in their FM transmitters, from a few kW up.
> John
> K5PRO
>
>> Message: 2
>> Date: Wed, 14 Dec 2011 20:38:52 -0700
>> From: "Mike Baker"<k7dd@cox.net>
>> Subject: Re: [Amps] Warm up and on time question...
>> To:<amps@contesting.com>
>> Message-ID:<04d401ccbadb$10702190$315064b0$@cox.net>
>> Content-Type: text/plain; charset="us-ascii"
>>
>> Speaking of warm up times and filament life got me to thinking about a
>> ramping switch system for the whole power supply.
>> As I understand it there are devices which will chop up the AC sine wave
>> into pieces like a PWM and slowly add more and more pieces until the full
>> sine wave is present on the load. I also understand they can be used in
>> reverse. Sort of like having an electronic Variac on the input side of the
>> supply.
>> Do any of you have a circuit diagram for such a system or could point me in
>> the right direction? I am not even sure what to call what I am looking for.
>> It sounds like a ramping soft start system and that would solve a lot of
>> problems with initial turn on of the filaments and the Plate supply.
>>
>> Thanks in advance.
>>
>> Mike Baker K7DD
>> K7dd@cox.net
>> All QSO's are uploaded to LOTW and EQSL.
>
>>
>
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