[Milsurplus] Fw: [ARC5] Cool New DC-DC Converter

[Jim Whartenby]

  It seems that there is no simple answer to this question.  Depending on the impedance of the power transformer, that is the equivalent series resistance seen by the tube filament, up to ten times the rated filament current can be drawn on a cold startup.  In other words, the higher the V/A rating of the power transformer, the higher the cold start current.  See: https://www.pupman.com/listarchives/2018/Feb/msg00091.phpandhttps://electronics.stackexchange.com/questions/279798/how-to-protect-valve-heaters-from-inrush-during-cold-starts/279812

The book "Getting the Most out of Vacuum Tubes" by Tomer talks about the reliability issues caused by the cold start problem, starting on page 12, but does not mention peak current values.  This book is available free on line.
Jim

      From: "arc5 at ix.netcom.com" <arc5 at ix.netcom.com>
 To: kb2vtl at gmail.com 
Cc: arc5 at mailman.qth.net; milsurplus at mailman.qth.net
 Sent: Thursday, March 15, 2018 8:44 AM
 Subject: Re: [Milsurplus] [ARC5] Cool New DC-DC Converter
  
 Good question.  Anyone?
 Sent from my Ain't Smart Phone.

------ Original message------Subject:Re: [ARC5] Cool New DC-DC ConverterSounds useful. Question:  how much more current does a tube filament take when cold?
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