in the spirit of FAR 23.1361
FYI Bob Nuckolls is tweaking Z101. As always, find the latest at http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/
Bob said you can delete the battery bus and use an in-line fuse holder for the CD bus but Bob would use a relay to switch the CD bus if the fuse is over 7.5A. Current draw does not matter, only fuse size, to limit energy delivered remote from the battery in case of accident or service preformed without disconnecting battery negative terminal.
Littlefuse advises fuse size should be, at minimum:
It's a great article Bob wrote "Magneto Switch Options", one of many great articles from him.
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My Final iteration DWG F105 ends up not having a battery bus.
Somewhere along the line Bob N. suggested a I put an inline fuse for the clearance delivery bus since it drew 3.2 amps. My thinking on the CD bus relay was similar. Since the CD bus amp draw was so low....simplify.
The SureFly will indeed be on the left side...I'll change that on the drawing. And thank you for the B.N. article on mag switches.
FYI Bob Nuckolls is tweaking Z101. As always, find the latest at http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/
Bob said you can delete the battery bus and use an in-line fuse holder for the CD bus but Bob would use a relay to switch the CD bus if the fuse is over 7.5A. Current draw does not matter, only fuse size, to limit energy delivered remote from the battery in case of accident or service preformed without disconnecting battery negative terminal.
Littlefuse advises fuse size should be, at minimum:
- Operating current/(.75 x temperature factor).
- 0.75 is an overhead factor to prevent nuisance blowing.
- If we say 170F for your inline fuse on the firewall, that makes temp factor 0.92 for an ATOF blade fuse.
- So fuse size should be minimum of 3.2/(.75*0.92) = 4.6A.
- This is without considering any current pulses above 3.2A.
- Therefore one could change the 15A CD bus fuse to 7.5A and have a robust fuse with no relay... except, as pointed out in the next post, the 7.5A fuse in the feed wire would be in series with the 7.5A fuse for the comm radio on the CD bus so that is not going to work.
- Ref Littlefuse documents "Fuseology Selection Guide" and "littelfuse_atof_datasheet.pdf"
It's a great article Bob wrote "Magneto Switch Options", one of many great articles from him.
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