Isn't inrush protection for filaments more or less incidental in designs
that use a single transformer?. Not that I'm an expert on it, but if you
check the handbook or other amp designs, it's usually related current
inrush at power-on related to attempting to charge the large capacitor
bank which presents an almost zero-Ohm load on the HV transformer
secondary. My Alpha 99 appears to have all voltages available off one
transformer, so its step start will affect all internal voltages
including filaments. I'm wondering if inrush protection on a filament
transformer really buys you much since, unlike the capacitors, the
filaments, while lower in R at turn-on, will continue to be low-R and
pull high current. The transformer and supply components should already
be designed for that. ?? It's been a while since I've boned up on
power supplies!
73, Duane
On Sun, 30 Jun 2002 10:12:08 -0400 Carter Grabarczyk <k8vt@ameritech.net>
writes:
> Well, at least for my Centurion (I'm the second owner, amp built in
> '93
> or '94 [?]), the answer is: yes and no.
>
> It all depends on how you define "in-rush protection". To my
> understanding, that phrase always referred to reduced voltage
> applied to
> the filaments for a short time right at turn on. From this
> viewpoint, my
> Centurion does NOT have in-rush protection. The full line voltage
> hits
> the primary of the filament transformer immediately.
>
> However, it DOES apply reduced voltage to the primary of the HIGH
> VOLTAGE transformer for one second (reference page 5-47 of
> Centurion
> manual).
>
> So, to summarize, "No" for filaments, "Yes" for high voltage (for my
> amp
> at least), your mileage may vary...
>
> 73/Carter/K8VT
>
> P.S.
> A guy in Florida is selling a filament in-rush protection kit for
> the
> Heath SB-220 amp, which also uses two 3-500s. Could it be adapted to
> the
> Centurion...???
>
> Duane A Calvin wrote:
> >
> > Yes, it has step-start inrush protection.
> >
> > 73, Duane
> >
> > On Sat, 29 Jun 2002 11:22:43 -0400 "John" <n1jp@arrl.net> writes:
> > > Anyone out there know if the Centurion has In-Rush Protection?
> > > Thanks
> > >
> > > John (N1JP)
> > > _______________________________________________
> > > TenTec mailing list
> > > TenTec@contesting.com
> > > http://lists.contesting.com/mailman/listinfo/tentec
> > >
> >
> > Duane A. Calvin, AC5AA
> > Austin, Texas
> > ac5aa@juno.com -or- ac5aa@austin.rr.com
> > Day: dacalvin@us.ibm.com
> > _______________________________________________
> > TenTec mailing list
> > TenTec@contesting.com
> > http://lists.contesting.com/mailman/listinfo/tentec
>
Duane A. Calvin, AC5AA
Austin, Texas
ac5aa@juno.com -or- ac5aa@austin.rr.com
Day: dacalvin@us.ibm.com
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