---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 04/21/18: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:39 AM - Re: Re: Z-12 contactor failure (Robert L. Nuckolls, III) 2. 08:15 AM - SD-8 Alternator Feed 30A Inline Fuse Location (Airdog77) 3. 08:25 AM - Re: SD-8 Alternator Feed 30A Inline Fuse Location (Charlie England) 4. 08:25 AM - Re: SD-8 Alternator Feed 30A Inline Fuse Location (user9253) 5. 08:37 AM - Re: SD-8 Alternator Feed 30A Inline Fuse Location (Airdog77) 6. 10:14 AM - Re: Re: Z-12 contactor failure (Robert L. Nuckolls, III) 7. 10:24 AM - Re: Re: Z-12 contactor failure (Robert L. Nuckolls, III) 8. 07:57 PM - Re: Bulb replacement for my Sandel 3308 EHSI (blues750) ________________________________ Message 1 _____________________________________ Time: 05:39:53 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z-12 contactor failure Agree the certified electrical system is much weaker and I found first hand that master switches are not well maintained, but I will attempt to bring this back around to the intent of my original post... Not trying to reinvent anything. This will most likely remain a philosophical discussion for me as Z-12 is already quite robust as compared to the certified planes I fly in that E-bus devices will still be available on battery + internal battery backups, etc. I have found very little information specific to protecting for master contactor failure. Because it's so rare . . . and, with the carefully contrived architecture and preventative maintenance, it's failure does not represent a hazard to comfortable termination of flight. So is the philosophy for Z-12 that it is not worth worrying about since E-bus will still operate? The whole airplane will probably operate. Z-12 is simply an illustration of how the secondary, engine driven alternator was incorporated into TC aircraft. It was simply added to the distribution system as a second source with the ability to support plenty of electro-whizzies on the panel. I can accept this, I just am confused when I see Z-13/8 that connects the alternator on the battery side. Can anyone explain the reason for the difference? Sure. Z13/8 is a three layer electrical system. (1) Battery only. E-bus powered appliances, no contactor loads Endurance implications: "Plan C" loads tailored to known battery capacity such that battery-only endurance goals are met. (2) Battery + 8. E-bus powered appliances, contactor load optional depending on "Plan B" loads. Loads tailored to hold battery in reserve for descent and approach to landing. Electrical endurance essentially unlimited. Descent and approach to landing loads can depend on known battery capacity to supplement the 8A engine driven power source. (3) Battery + Main Alternator. Normal "Plan A" ops. No limits on electrical loads. The three-layer system is practical only on OBAM aircraft . . . the 337 or STC to convert a TC aircraft would be prohibitive and would not materially reduce risk. Bob . . . ________________________________ Message 2 _____________________________________ Time: 08:15:03 AM PST US Subject: AeroElectric-List: SD-8 Alternator Feed 30A Inline Fuse Location From: "Airdog77" Bob, In your response on the Z13 Battery Bus Protection question in a very recent post, you reminded us that > Recall that circuit protection is for WIRES . . . and that the protective device is installed as close as practical to the SOURCE of energy that puts the wire at risk. A friend of mine asked me a question on my Z-13/8 configuration that stumped me, so I thought I'd ask you. In keeping in line with your statement above, in Z-13/8 why is the inline 30A fuse for the SD-8 wire connection from the battery contactor to the SD-8's S704-1 relay placed within 6 inches or less from the battery contactor, when the SD-8 is the source of energy? Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479470#479470 ________________________________ Message 3 _____________________________________ Time: 08:25:13 AM PST US Subject: Re: AeroElectric-List: SD-8 Alternator Feed 30A Inline Fuse Location From: Charlie England On 4/21/2018 10:14 AM, Airdog77 wrote: > > Bob, > > In your response on the Z13 Battery Bus Protection question in a very recent post, you reminded us that >> Recall that circuit protection is for WIRES . . . and that the protective device is installed as close as practical to the SOURCE of energy that puts the wire at risk. > A friend of mine asked me a question on my Z-13/8 configuration that stumped me, so I thought I'd ask you. > > In keeping in line with your statement above, in Z-13/8 why is the inline 30A fuse for the SD-8 wire connection from the battery contactor to the SD-8's S704-1 relay placed within 6 inches or less from the battery contactor, when the SD-8 is the source of energy? > > Wade > I'm not Bob, but an alternator wire should be big enough to handle everything an alternator can throw at it, meaning the alternator can't damage it. But... The battery *can* damage it, so the protection is at the potential source of the damage. That help? --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 4 _____________________________________ Time: 08:25:15 AM PST US Subject: AeroElectric-List: Re: SD-8 Alternator Feed 30A Inline Fuse Location From: "user9253" There are two sources of energy, the battery and SD-8. The SD-8 is self current limiting. It can put out perhaps 10 amps at most. Its output does not need to be fused. The battery can put out hundreds of amps and possibly do lots of damage. Placing the fuse near the battery will minimize the danger. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479471#479471 ________________________________ Message 5 _____________________________________ Time: 08:37:02 AM PST US Subject: AeroElectric-List: Re: SD-8 Alternator Feed 30A Inline Fuse Location From: "Airdog77" Makes all the sense in the world.... now that you guys explained it!! Crystal clear. Always good to learn something new! Thanks Joe & Charlie! Cheers, Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479473#479473 ________________________________ Message 6 _____________________________________ Time: 10:14:41 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z-12 contactor failure > >This makes perfect sense to me. Now look at Z-12 - the primary and >backup alternators are both connected the same way - to the main >bus. If you turn off the master both alternators are isolated from >the battery. This means battery only operation unless the >alternators remain stable without battery. Why do it this way? The >only difference I see is the backup alternator is the larger 20A vs 8A. > >To ask another way. Why not connect the larger 20A backup >alternator in the same way as Z-13/8 ( with relay and switch )? Is >this not advisable due to the higher current being switched or some >other reason? The e-bus was conceived one evening about 1988 in conversation with a LongEz builder in California. This fellow did a lot of long distance travel over mountains. I don't recall if his airplane had a starter . . . don't think it did because I do recall that he was fitted with a pretty light battery in the nose. The design goal being pondered was how to create a battery-only endurance greater than his fuel endurance . . . which was rather long. At that time, his electrical endurance loads were as I recall, about 3 amps. A battery contactor draws about 0.8A after warm up . . . enough snort to run a couple of useful electro-whizzies yet this energy was tossed off as heat. His SD-8 would support normal flight loads including contactor. Emacs! His endurance loads must have been a bit less than 3A because I recall we decided that a new 18a.h. battery would carry his anticipated loads for 6 hours, hence his 4-hour design goal would be satisfied to 75% of new capacity whereupon the battery gets replaced. So the e-bus was conceived as a method for setting up a fixed, predictable battery-only endurance load with a simple re-positioning of two switches. Lots of Ez aircraft had only SD8 alternators on the drive pad, no other alternator and no starter. The B&C line of light weight starters and alternators encouraged the Ez crowd on to the next evolutionary step. Added weight on the extreme rear of the a/c drove a need for ballast in the nose . . . ballast that was best achieved with a larger battery as opposed to bags of lead shot! The 24 a.h. battery was the next step up. The SD-8 could be left in place on the drive pad for a weight penalty of about 4 pounds. Hence, Z13/8 germinated from the evolving goals of Long-Ez owners in the 1990 time frame. At one time, I did have a Z13/20 architecture which was discussed here on List and I think a few installations were made. I was never happy with it as it offered no particular advantages over Z12 and was un=necessarily complex. There was no pressing need to eliminate contactor loads on the much larger S/B alternator so it was removed from the 'Connection after a few years. Bob . . . ________________________________ Message 7 _____________________________________ Time: 10:24:58 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z-12 contactor failure > His endurance loads must have been a bit less than > 3A because I recall we decided that a new 18a.h. > battery would carry his anticipated loads for 6 > hours, hence his 4-hour design goal would be > satisfied to 75% of new capacity whereupon > the battery gets replaced. Hmmmm . . . my recollection of details may be a bit fuzzy after 30 years, 4 hours is 66% of new . . . anyhow, this illustrates the thought processes for design decisions. Bob . . . ________________________________ Message 8 _____________________________________ Time: 07:57:27 PM PST US Subject: AeroElectric-List: Re: Bulb replacement for my Sandel 3308 EHSI From: "blues750" Thanks Bob, my main concern was inadvertently trashing the Sandel somehow. If that is a non-factor I'm game to see what the LED presentation would be like. Will indeed report back when I've got some field test info! Dave Read this topic online here: http://forums.matronics.com/viewtopic.php?p=479476#479476 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.