[Heathkit] SB 200 Linear Amp

[jeremy-ca]

Inrush current worry is as overblown as man made global warming.

The Heath SB series of amps have more than enough protection DESIGNED into 
the transformers. At turn on when the caps present a dead short the 
transformer core is saturated effectively acting as a time delay to the 
voltalge build up.

MOST ham amps do not use inrush circuits as smart engineers have made it 
uneccessary. However a few companies are more than willing to put their hand 
in your wallet under the PT Barnum belief that a sucker is born every 
minute.

Carl
KM1H


----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at verizon.net>
To: <heathkit at mailman.qth.net>
Sent: Tuesday, November 06, 2007 3:03 PM
Subject: Re: [Heathkit] SB 200 Linear Amp


> >From an article in a GE Ham Tips, the dynamic regulation of power
> supplies for SSB use was discussed. It was suggested that the
> higher the value of filter capacitance in the output of the power
> supply, the better the dynamic regulation.
>
> However, there is, obviously, a limit to how much one dares use,
> since the inrush current can be very high with large capacitors.
>
> I have not yet satisfied myself on the best method of handling
> inrush current to the HV supply.
>
> The OT used to use a time-delay relay of one kind or another to cut
> out a series resistor to the primary, and I favor that method since it
> is pretty fail-safe...generally...
>
> However, I have also been very curious about those solid-state
> inrush current limiters, specifically those made by Ametherm. I
> understand that they run quite hot, however.
>
> So, what might be the consensus here on these issues?
>
> 1) Maximum capacitance in HV supplies
>
> 2) Inrush current limiting.
>
> Ken Gordon W7EKB
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