---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 11/02/18: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:55 AM - Re: Question on Grounding (ronaldcox) 2. 08:14 AM - Splice wires (Dick Gurley) 3. 08:33 AM - Re: E-Bus Fuse Size (skywagon185guy) 4. 08:58 AM - Re: Splice wires (Robert L. Nuckolls, III) 5. 09:16 AM - Re: Re: E-Bus Fuse Size (Robert L. Nuckolls, III) 6. 10:19 AM - Re: E-Bus Fuse Size (user9253) 7. 10:51 AM - Re: Re: E-Bus Fuse Size (Robert L. Nuckolls, III) 8. 12:02 PM - Re: Splice wires (Dick Gurley) 9. 01:12 PM - Re: Re: E-Bus Fuse Size (skywagon185guy) 10. 03:49 PM - Dual Battery Dual Alternator Power Distribution System (lwesterlund) 11. 09:48 PM - Re: Splice wires (Art Zemon) 12. 11:02 PM - Re: Splice wires (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:55:16 AM PST US Subject: AeroElectric-List: Re: Question on Grounding From: "ronaldcox" Rocketman1988 wrote: > Sorry I asked... And that is exactly why the rule is there. We need the level of our discussion to be such that NO ONE is ever sorry they asked. Every year or two someone shows up here and decides they need to kick over the chairs and pee in all the corners. Fortunately, it usually works itself out amicably, as I hope it has here. No need to be sorry. Your question was not out of line. It's exactly what we're all here for. The sharing of questions and ideas, and hopefully some answers. Don't let this scare you away. -------- Ron Cox Glasair Super II F/T Under Construction at C77 - Still just about to fly! Read this topic online here: http://forums.matronics.com/viewtopic.php?p=484240#484240 ________________________________ Message 2 _____________________________________ Time: 08:14:43 AM PST US From: Dick Gurley Subject: AeroElectric-List: Splice wires What is the proper technique for splicing two #14 wires to one #16 wire. Sorry for the newbie question. Thank you Sent from my iPhone ________________________________ Message 3 _____________________________________ Time: 08:33:28 AM PST US From: skywagon185guy Subject: Re: AeroElectric-List: E-Bus Fuse Size Joe, . . . didn't you mean "parallel" instead of series. . . ?? On Wed, Oct 31, 2018 at 5:40 PM user9253 wrote: > > A pilot recently experienced an instrument panel blackout at night. When > he turned on the E-Bus switch, the panel briefly came back on, but soon > went black again. Luckily the weather was good and he landed safely. You > can read about it here. > http://www.vansairforce.com/community/showthread.php?t=165520 > The E-Bus was protected by 15 amp fuses. Evidently the second and third > owners of the aircraft connected more loads to the E-Ebus, eventually > overloading it. > If two fuses are connected in series, even if one is bigger, either one or > both could blow in case of hard ground fault. > Should the E-Bus have main fuses? > If so, then how much larger should the main fuse be than a branch circuit > fuse? > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=484131#484131 > > ________________________________ Message 4 _____________________________________ Time: 08:58:05 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Splice wires At 10:09 AM 11/2/2018, you wrote: > >What is the proper technique for splicing two #14 wires to one #16 >wire. Sorry for the newbie question. Thank you > >Sent from my iPhone Lots of ways work just fine. you can use a crimped butt splice, although you'd have to use a yellow splice and double up one of the wires. You can do a soldered lap-joint covered in heat shrink. But I'm curious as to the mixture of wire sizes. What power do these wires carry and what is the circuit protection for those wires? Bob . . . ________________________________ Message 5 _____________________________________ Time: 09:16:43 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: E-Bus Fuse Size At 10:12 PM 11/1/2018, you wrote: > >What I meant by being in series are the input fuse to the E-bus and >one of the E-Bus loads. My concern is what will happen in case a >load circuit shorts to ground. For a fraction of a second, the >current arcing across a fuse will exceed the fuse value. That high >arcing current could be enough to blow an upstream fuse, even if >that upstream fuse has a higher current rating. Ever notice that >circuit breakers in a home service entrance panel are labeled "10K >Amps" even though the breaker size is 15 or 20 amps? The reason is >that when the circuit breaker trips with a dead short, the current >arcing across the opening contacts is only limited by the power >company's ability to provide it. Thus the circuit breaker is >capable of withstanding very high arcing current up to 10K amps for >a fraction of a second without blowing itself apart. That's not a concern. Consider the ac power distribution in your house. A hand-held appliance may have some small protective device inside it . . . then you move up the chain to a breaker in your entry box. There may be a mains breaker upstream in the same box. There are probably fuses in the transformer behind your house. The neighborhood distribution system has yet more upstream fuses. From there on up the chain, fuses are generally replaced with circuit breakers all the way back to the power plant. Any one of those protective devices can be faulted without opening the upstream protection . . . IN SPITE of whatever pre-heating may be present due to other running loads sharing the same feeder. You can be sure that the I(squared)t fusing constant for every device is much greater than any downstream device, much less than any upstream device. The protection architecture behaves gracefully irrespective of the system's source impedance . . . which sets the maximum, instantaneous fault current. The thing that made our fuse choices more critical was the fact some devices were fed by upstream devices of the same class . . . i.e. plastic automotive fuses. This is not inherently a bad thing but it does take some careful design combined with verification testing. I slipped up in not evolving the protection philosophy along with step with expanded design goals for the e-bus. This placed the uninformed builder at risk for the 'Dark E-bus Syndrome'. Going foreward with Z36 should eliminate that risk. Bob . . . ________________________________ Message 6 _____________________________________ Time: 10:19:38 AM PST US Subject: AeroElectric-List: Re: E-Bus Fuse Size From: "user9253" > Joe, . . . didn't you mean "parallel" instead of series. . . ?? No, I meant series. There is a fuse protecting the E-Bus and there are individual loads on the E-Bus each protected by a fuse. The fuse for the whole E-bus and a load fuse are in series. The fuse protecting the whole E-Bus needs to be chosen so that a hard short to ground on an individual load does not blow both the load fuse and the main E-Bus fuse. Bob has addressed this issue with his proposed Z-36 using a MANL30 protecting a heavy duty E-Bus. Builders keep adding more and more loads to an E-bus that was originally designed for minimum loads. A person I know was working on an apartment kitchen range outlet. He stuck a screwdriver in where it should not have been and tripped not only the circuit breaker for the range, but also the main breaker for the whole building. He had to get the apartment manager to unlock the utility room and reset the building main breaker. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=484248#484248 ________________________________ Message 7 _____________________________________ Time: 10:51:10 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: E-Bus Fuse Size > A person I know was working on an apartment kitchen range > outlet. He stuck a screwdriver in where it should not have been > and tripped not only the circuit breaker for the range, but also > the main breaker for the whole building. He had to get the > apartment manager to unlock the utility room and reset the building > main breaker. Defective or mis-applied breaker . . . it's a fundamental design REQUIREMENT to prevent fault effects from propagating outward or upward in a complex system. Bob . . . ________________________________ Message 8 _____________________________________ Time: 12:02:12 PM PST US From: Dick Gurley Subject: Re: AeroElectric-List: Splice wires Thank you Bob - The two wires come from a heated Garmin pitot tube system. Garmin twisted a nd soldered the two wires together at the factory. The Garmin G3X manual cal ls for 14 gauge wire for the length required (>21 feet). The manual also cal ls for a 20 amp fuse for power onto the control box. The max current draw is listed at 12 amps. I measured the provided twisted and soldered wire to obtain a 12 gauge equiv alent. Where can I learn about a soldered lap joint with heat shrink Than you again Dick Sent from my iPhone > On Nov 2, 2018, at 11:57 AM, Robert L. Nuckolls, III wrote: > > At 10:09 AM 11/2/2018, you wrote: >> >> What is the proper technique for splicing two #14 wires to one #16 wire. S orry for the newbie question. Thank you >> >> Sent from my iPhone > > Lots of ways work just fine. you can use a crimped > butt splice, although you'd have to use a yellow > splice and double up one of the wires. > > You can do a soldered lap-joint covered > in heat shrink. > > But I'm curious as to the mixture > of wire sizes. What power do these wires carry and > what is the circuit protection for those wires? > > ========================== ========================== ========================== ========================== ========================== ========================== ========================== ==== ________________________________ Message 9 _____________________________________ Time: 01:12:59 PM PST US From: skywagon185guy Subject: Re: AeroElectric-List: Re: E-Bus Fuse Size . . . you are certainly right; I didn't consider that you were talking about "branches". My email gets staged with the earlier first and I did not see your follow-up until I had already stepped on my xxx with a reply. "Must remember to read the entire thread. . .=F0=9F=99=84 " On Fri, Nov 2, 2018 at 10:25 AM user9253 wrote: > > > > Joe, . . . didn't you mean "parallel" instead of series. . . ?? > > No, I meant series. There is a fuse protecting the E-Bus and there are > individual loads on the E-Bus each protected by a fuse. The fuse for the > whole E-bus and a load fuse are in series. The fuse protecting the whole > E-Bus needs to be chosen so that a hard short to ground on an individual > load does not blow both the load fuse and the main E-Bus fuse. Bob has > addressed this issue with his proposed Z-36 using a MANL30 protecting a > heavy duty E-Bus. Builders keep adding more and more loads to an E-bus > that was originally designed for minimum loads. > A person I know was working on an apartment kitchen range outlet. He > stuck a screwdriver in where it should not have been and tripped not only > the circuit breaker for the range, but also the main breaker for the whol e > building. He had to get the apartment manager to unlock the utility room > and reset the building main breaker. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=484248#484248 > > =========== =========== =========== =========== =========== =========== > > ________________________________ Message 10 ____________________________________ Time: 03:49:21 PM PST US Subject: AeroElectric-List: Dual Battery Dual Alternator Power Distribution System From: "lwesterlund" Im looking for some help in reviewing a draft Dual Battery/ Dual Alternator (DBDA) power distribution architecture for an RV-14A. I started with Bob Nuckolls Z-14 system and Ive attempted to modify it to capitalize on the dual power feed capabilities of the newest generation of avionics. My mission is IFR in the Pacific Northwest where theres lot of clouds and lots of rocks in those clouds. Accordingly, the proposed system utilizes two alternators and two EarthX batteries. The 60W primary alternator will handle all normal loads at 60% capacity. The 20-30W accessory-pad mounted auxiliary alternator will handle its normal loads at 50% capacity, and when called upon, all IFR critical loads indefinitely at 66%+ loading. The two batteries provide a third level of redundancy. The batteries are not wired for cross connection for starting. I removed that from Bob's Z-14 - if I cant start the engine with just the primary battery, its time to get a new battery. Power is distributed through two buses: 1. The Primary Bus feeds all dual feed components as well as the non-critical single feed components. Ive elected to use the Vertical Power X Pro to control these loads. I realize the VPX does somewhat increase the risk of a single point of failure (not withstanding its two independent controllers and two buses) but even if the VPX did go dark, I could still get home on the completely independent Aux Bus with at least as much capability and safety as I get flying spam cans now. 2. The Aux Bus provides redundant power to all critical IFR dual feed components (PFD, ADAHRS) as well as to several always-nice-to-have dual feed components (MFD, AP, Transponder). It also provides sole power to the WAAS GPS/NAV/COM (which only has a single power feed) and several other redundant loads. The Aux Bus will be set to run at a slightly lower voltage than the Primary Bus, so the Primary Alternator will normally carry the full load (excepting the GTN650, stall warning, and optical fuel level detector). Should Primary Bus voltage fall during starting, or due to a Pri Alternator failure, the dual feed components will automatically be picked up by the Aux Bus with no pilot intervention required. Regarding the ubiquitous always-hot battery bus, my hypothesis is that its no longer necessary given advances in technology. In Z-14 (and earlier in Chapter 17 or The AeroElectric Connection), Bob lists the following loads as worthy of a direct connection to the battery: Ignition Fuel pump(s) Dome light Clock Radio mem My initial attempts at developing an architecture included a battery bus for those loads. However, as I started to work through failure modes, the list of battery bus-worthy loads got smaller and smaller. For instance, with dual P-mags (which the manufacturer recommends not connecting to an always hot battery bus) you only need power to one P-mag at start. Above 700 RPM both with self-excite so even in the unlikely event you lose both bus contactors, the plugs will fire and the engine will spin. The only recommended battery bus load that gives me a little pause is the fuel pump. But, as shown, a simple single pole double throw switch should let me connect to either bus. I would need to lose both buses and the mechanical fuel pump to lose fuel to the engine. Absent battle damage, it seems like the chance of fuel starvation due to an electrical problem is pretty remote. Regarding bus management, normal operation would be to turn on the G5 (to check G5 back-up battery operation) then the Aux Bus during pre-start to check voltage and set up the avionics. The Primary Bus, electric fuel pump and P-mags would be turned on just prior to engine start-up. If the twirley thingy in front spins, youre good to go. When done flying, the procedure would be to turn off the Primary Bus (to confirm load pick-up by the Aux Alt), then secure the Aux Bus, then the G5 which has its own battery, and finally the P-mags. In the event of an electrical fire in IMC, opening the Primary Battery relay would dump about 70% of loads and feeds. I would still have a full complement of IFR critical equipment running on the Aux Bus. If opening the Primary Battery Relay doesnt isolate power to the fire, opening the Aux Battery relay would dump the balance of loads and feeds. At that point, Id still have self-excite power to run the P-mags and the back-up battery to power the G5 EFIS to keep the plane upright. In VFR conditions, I would dump both Pri and Aux buses immediately. So, what I have I missed? Or misunderstood? Or miscalculated? Does eliminating the battery bus increase risk in some unintended way? Im 100% sure Ive missed something small, complex, and nuanced. Im also pretty sure Ive missed something really, really big. Any feedback would be much appreciated. Thanks. Lance Beaverton, OR, RV-14A - Emp & Fuse Done, Finish Kit in Progress, QB Wings Ordered Read this topic online here: http://forums.matronics.com/viewtopic.php?p=484257#484257 Attachments: http://forums.matronics.com//files/rv_power_distribution_v4_137.pdf ________________________________ Message 11 ____________________________________ Time: 09:48:20 PM PST US From: Art Zemon Subject: Re: AeroElectric-List: Splice wires On Fri, Nov 2, 2018 at 2:21 PM Dick Gurley wrote: > Where can I learn about a soldered lap joint with heat shrink > Dick, I wrote it up with photos in my blog post Physical & Electrical Considerations when Mounting Avionics . That post also includes a link to Bob's shop notes on "Poor Man's Solder Sleeves" which have all of the detailed instructions that you will need. Also see my photos near the bottom of my blog post Wiring Harness Installed because there are some splices with 1 wire coming into the splice and 2 wires going out the other side. Cheers, -- Art Z. -- https://CheerfulCurmudgeon.com/ *"Be kind, for everyone you meet is fighting a hard battle."* ________________________________ Message 12 ____________________________________ Time: 11:02:48 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Splice wires At 11:59 AM 11/2/2018, you wrote: >Thank you Bob - > >The two wires come from a heated Garmin pitot tube system. Garmin >twisted and soldered the two wires together at the factory. The >Garmin G3X manual calls for 14 gauge wire for the length required >(>21 feet). The manual also calls for a 20 amp fuse for power onto >the control box. The max current draw is listed at 12 amps. > >I measured the provided twisted and soldered wire to obtain a 12 >gauge equivalent. > >Where can I learn about a soldered lap joint with heat shrink https://tinyurl.com/c5v2xvm Bob . . . ------------------------------------------------------------------------------------- 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.