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@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/Chapter10Su...
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 _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb