[amsat-bb] Antenna Burn Resistor data

[Glen Zook]

The whole idea behind a burn resistor is for a mechanical failure which then releases the antenna.  Putting a fuse in line would not result in any mechanical failure because the body of the fuse would still be in place.  A fuse link, that is a piece of wire without any housing, might work.  However, finding something, that could withstand the forces in launching that would still "fail" when the voltage was applied, might be problematic.
 
Glen, K9STH 
AMSAT 239 / LM 463

Website:  http://k9sth.net


On Saturday, September 6, 2014 9:15 AM, Ross Whenmouth <ross at topwire.co.nz> wrote:
 


Bob, does your mass budget allow you to include a fuse in series with 
the burn resistor?

eg Looking at:
http://www.matronic.de/pdf/herstellerkataloge/littelfuse_katalog/Chapter10SurfaceMountFuses.pdf

Your 15R burn resistor will draw ~ 0.5A from your 7.5V supply?
Looking at the fuse curves for the "FLAT-PAK Slo-Blo Fuse 203 Series" on 
page 23 of that PDF, the 1/4A variant of those fuses should open after 
about 6 seconds @ 0.5A (might blow a bit quicker in a vacuum though 
since there is no atmosphere to convect heat away from the fuse?)

There will be other suitable fuses - the above is just an example (I do 
not work for Littelfuse).


73 ZL2WRW
Ross Whenmouth
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