[Amps] Filament Xfmr

[Carl]

Too many rely on the NEC table which hasnt been in touch with reality for decades unless you build your amps with house wiring (-; Thats the last place Id look.

Carl
KM1H




  ----- Original Message ----- 
  From: Gudguyham at aol.com 
  To: km1h at jeremy.mv.com ; n4kwpete at centurylink.net ; amps at contesting.com 
  Sent: Sunday, July 08, 2012 2:15 PM
  Subject: Re: [Amps] Filament Xfmr


  You will notice at looking at the NEC ampacity table it is categorized by the type of insulation on the wire.  They generally do not cover the types of wire found within devices, only those used in electrical construction.  Simply saying #14 wire handles 15A is rather vague  unless we know exactly the type of wire and the insulation on it.  Although the insulation changes the ampacity a bit, it is not worlds away. You would be surprised if you looked at the ampacity  of wire in free air however.

  In a message dated 7/8/2012 1:50:49 P.M. Eastern Daylight Time, km1h at jeremy.mv.com writes:
    There are plenty of non Teflon insulations that go from 105C to higher. 
    Modern vehicles have gone to 175-200C wiring in some areas as a means of 
    reducing copper weight..

    Carl
    KM1H


    ----- Original Message ----- 
    From: <Gudguyham at aol.com>
    To: <n4kwpete at centurylink.net>; <amps at contesting.com>
    Sent: Sunday, July 08, 2012 1:17 PM
    Subject: Re: [Amps] Filament Xfmr


    > If the wire is Teflon it will probably be fine.  Can you tell if it  is?
    >
    >
    > In a message dated 7/8/2012 1:01:03 P.M. Eastern Daylight Time,
    > n4kwpete at centurylink.net writes:
    >
    > I  ordered a filament transformer for a 4CX1500B linear that I am 
    > building.
    >
    > When I received the transformer all looked great to me except for the
    > secondary pigtail wires.  The tube requires 6vac at 10amps, the  pigtails
    > provided are about five inches long and are a #18 well insulated  wire.
    > Being concerned with the wire size it put the transformer under load  and
    > drawing 10amps  left it that way for about an hour.  The  wire did not 
    > over
    > heat in that time but hey how about hours of  operating.  Should I be
    > concerned with the wire size.  I have  looked for information on how to
    > figure how much current various wire  sizes can carry and at various
    > voltages
    > and have not found  anything.
    >
    > 73 Pete  N4KW
    >
    > _______________________________________________
    > Amps mailing  list
    > Amps at contesting.com
    > http://lists.contesting.com/mailman/listinfo/amps
    >
    > _______________________________________________
    > Amps mailing list
    > Amps at contesting.com
    > http://lists.contesting.com/mailman/listinfo/amps
    >
    >
    > -----
    > No virus found in this message.
    > Checked by AVG - www.avg.com
    > Version: 10.0.1424 / Virus Database: 2437/5118 - Release Date: 07/08/12
    > 



------------------------------------------------------------------------------

  No virus found in this message.
  Checked by AVG - www.avg.com
  Version: 10.0.1424 / Virus Database: 2437/5118 - Release Date: 07/08/12