[Amps] Warm up and on time question...

[Roger (K8RI)]

On 12/16/2011 3:49 PM, Carel, pc5m wrote:
> Hi Mike,
>
> Have a look at: http://www.pc5m.net/projects/filament-inrush-protection
>
> Is in use for my TH289 (45amps of filament current) amplifier.
>
> Gl, Carel
>
> -----Original Message-----
> From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
> Behalf Of Mike Baker
> Sent: donderdag 15 december 2011 4:39
> To: amps at contesting.com
> Subject: Re: [Amps] Warm up and on time question...
>
> 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.

Just use a Triac and let it ramp up the voltage over a few seconds...say 
5 or 10.
After the ramp up, switch out the Triac with a relay as they tend to be 
a bit noisy. Mostly it's the diac keying that's noisy.

73

Roger (K8RI)

> 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 at cox.net
> All QSO's are uploaded to LOTW and EQSL.
>
>
>
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