This makes a case that it isn't the rate at which the filament
temperature rises, but in stead the fact that it passes through a
particular temperature at all. If it passes through ~900F, then the
Miller-Larson effect occurs and there's nothing we can do to alter it.
I've always treated the amp carefully and once I turn it on (it's an
AL-1200 with a 3CX1200A7), it stays on for the duration of my activity.
I'll keep doing that. I have a a spare tube, but they are very
expensive beasts!
Kim N5OP
On 12/27/2017 2:34 PM, Bryan Swadener via Amps wrote:
FWIW, Mike WØBTU put this together, s'plaining the "Miller-Larson Effect":
http://www.w0btu.com/miller-larson_effect.html.
Though, in some cases (such as in the SB-220), there's little/no benefit,
as the filament transformer limits the current. In those cases, you're
mainly extending the life of the ON/OFF switch from yuuuge inrush current
caused by overly large HV filter capacitance.
vy 73,
Bryan WA7PRC
Date: Wed, 27 Dec 2017 06:25:27 -0600
From: Jim W7RY
Subject: Re: [Amps] Soft Start
Soft start (I call it step start) does reduce filament inrush current. As
long as it's on the filament transformer primary.
Which it is in the SB200, SB220, TL922, L4B and TenTec Titan... And many
others.
73
Jim W7RY
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
--
Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)
/"In theory there is no difference between theory and practice. But, in
practice, there is." //– Attributed to many people; it’s so true that it
doesn’t matter who said it./
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|