[ARC5] Filament Power Sources

[Fuqua, Bill L]

  If it occurred while transmitting, it more likely that RF got back into the PC power supply and affected its 
regulation circuit causing the output voltage to go above 5 volts DC.
73
Bill wa4lav

________________________________________
From: arc5-bounces at mailman.qth.net [arc5-bounces at mailman.qth.net] on behalf of Ian Wilson [ianmwilson73 at gmail.com]
Sent: Saturday, August 24, 2013 12:59 PM
To: Robert Eleazer
Cc: ARC5
Subject: Re: [ARC5] Filament Power Sources

I have blown a filament on a 4-125A when using a PC power supply. While
a single case doesn't prove anything, this has never happened when using
a transformer for filament power.

I wonder whether the inductance of a real transformer acts to limit the
starting transient, whereas a switching PSU is much stiffer and might stress
a brittle filament on switchon. I am told that PC PSUs can be made somewhat
soft-starting by adding a capacitor across the reference voltage resistor,
but
haven't tried it.

73, ian K3IMW



On Sat, Aug 24, 2013 at 5:35 PM, Robert Eleazer <releazer at earthlink.net>wrote:

> If you needed a lot of filament power at 6V, would there be anything wrong
> with adjusting a 5VDC power supply up to 6V?  I have one of those that will
> adjust up to 6V via a pot control and it'll put out 100 amps.
>
> Wayne
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
______________________________________________________________
ARC5 mailing list
Home: http://mailman.qth.net/mailman/listinfo/arc5
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:ARC5 at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html