---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 01/08/14: 20 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:59 AM - Re: Proposed new Z diagram? (Thomas E Blejwas) 2. 06:13 AM - Re: Proposed new Z diagram? (Robert L. Nuckolls, III) 3. 06:19 AM - Re: Re: Proposed new Z diagram? (Robert L. Nuckolls, III) 4. 07:02 AM - Re: Proposed new Z diagram? (Dj Merrill) 5. 08:58 AM - Re: Re: Proposed new Z diagram? (Dj Merrill) 6. 09:07 AM - DIY Marker beacon antenna (Roger & Jean) 7. 10:08 AM - Re: DIY Marker beacon antenna (R. curtis) 8. 10:21 AM - Thoughts on a few electrical system configurations? (digidocs) 9. 10:52 AM - Re: DIY Marker beacon antenna (Tim Andres) 10. 11:54 AM - Re: Re: Proposed new Z diagram? (Dj Merrill) 11. 11:55 AM - Re: DIY Marker beacon antenna (BobsV35B@aol.com) 12. 01:40 PM - Re: Thoughts on a few electrical system configurations? (Bill Watson) 13. 01:57 PM - Re: Re: Proposed new Z diagram? (John W Livingston) 14. 02:28 PM - Re: Re: Proposed new Z diagram? (Robert L. Nuckolls, III) 15. 02:38 PM - Re: Thoughts on a few electrical system configurations? (Jim Berry) 16. 03:23 PM - Re: DIY Marker beacon antenna (Roger & Jean) 17. 05:16 PM - Re: Re: Proposed new Z diagram? (Dj Merrill) 18. 06:10 PM - Re: Re: Proposed new Z diagram? (Jeff Luckey) 19. 06:17 PM - Re: Re: Proposed new Z diagram? (Dj Merrill) 20. 06:18 PM - Re: Re: Proposed new Z diagram? (Dj Merrill) ________________________________ Message 1 _____________________________________ Time: 05:59:05 AM PST US Subject: Re: AeroElectric-List: Proposed new Z diagram? From: Thomas E Blejwas Bob, You wrote: > Assuming that the Viking engine with the as- > proposed alternator does run gracefully in > an alternator only mode, then the whole inter-linked > switch philsosopy for battery and alternator is > moot. This figure illustrates the opptions for > being relieved of that constraint . . . > > http://tinyurl.com/mhblorq The split of the "master" switch also allows the engine to be operated from the aux battery and alternator. Why would you? I can imagine my battery monitor on the main battery indicating very high charging current and low voltage. I would interpret this as something wrong with the main and switch to the aux. Because the alternator for the Viking is an internally regulated ND, I would use a contactor with a "crow bar" for a disconnect, in the event of an o.v. runaway. I would also connect the alternator sense wire without a switch to the "motive" bus, so it can't be accidentally shut down while the engine is running and destroy the permanent-magnet alternator. I would still be able to pull the alternator CB in the event of an emergency. Hope these make sense. Tom Sent from my iPad > On Jan 6, 2014, at 8:01 PM, "Robert L. Nuckolls, III" wrote: > > > > >> the alternator will always be turned off first >> before the main battery contactor is turned off (ie, no alternator-only >> mode). With either the aux or main contactors on, both power buses will >> be enabled and there is no independent control to turn each bus off >> individually. > > Assuming that the Viking engine with the as- > proposed alternator does run gracefully in > an alternator only mode, then the whole inter-linked > switch philsosopy for battery and alternator is > moot. This figure illustrates the opptions for > being relieved of that constraint . . . > > http://tinyurl.com/mhblorq > > >> Dual-Bat Z-7 requires two switches to shut down all power, and mine >> requires three, as you indicate. I could replace the alternator and >> main switches with a combined switch similar to Z-7, removing the >> alternator-only mode, which may be a good thing to do and simplifies the >> user experience, as well as allowing for each power bus to be separated >> and powered independently. I think the chances of both batteries >> failing and requiring an alternator-only mode are so remote that it is >> not worth worrying about. > > How does a battery fail? If such a failure occurs > in flight, how do you know it has happened? What > light comes on to say, "Battery X Fail"? > > You have articulated some goals for addressing > a constellation of failures as yet not clearly > defined. > > When conducting an FMEA on a system or product > the following questions are posed and answers > sought: > > How might this part fail? > > How will I know that it failed? Can the effects > of the failure be immediately known and > dealt with in a simple, prescribed manner? > > Is the failure pre-flight detectable? If not can > it be made detectable. I that's not possible/ > practical . . . what sort of testing is called > for and at what intervals? > > How does any particular failure impact probability > of comfortable termination of a flight? > > (a) Will any identified failure produce an immediate > risk to ship's systems? > > (b) Will any identified failure over-tax my abilities > to manage the event while maintaining competent > control of the airplane? > > I have split the DC POWER MASTER into two switches > which increases the number of power management controls > to a total of 6. That gives you 36 possible combinations > of switch positions some small number of which will > result in the engine stopping . . . so those are > easy to eliminate. Of the remaining combinations, > what are the criteria for selecting/rejecting any > combination that keeps the engine running and at least > some stuff lit on the panel? > > At some point, after all the colors are laid down > with the favorite brush strokes, you need to craft > the pilot's operating handbook for how the switches > are used. Do all those options serve a predictable, > useful purpose? > > It's one thing to have so many options and control > over those options . . . consider that each option > should be deduced and prescribed in advance. Lots > of options can work against you should one become reduced > to a game of "flipping switches until things work better" > while distracting concentration from your duties as a > pilot. > > > > Bob . . . > > > > ________________________________ Message 2 _____________________________________ Time: 06:13:19 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Proposed new Z diagram? At 07:57 AM 1/8/2014, you wrote: > > >Bob, > >You wrote: > > Assuming that the Viking engine with the as- > > proposed alternator does run gracefully in > > an alternator only mode, then the whole inter-linked > > switch philsosopy for battery and alternator is > > moot. This figure illustrates the opptions for > > being relieved of that constraint . . . > > > > http://tinyurl.com/mhblorq > >The split of the "master" switch also allows the engine to be >operated from the aux battery and alternator. Why would you? I can >imagine my battery monitor on the main battery indicating very high >charging current and low voltage. I would interpret this as >something wrong with the main and switch to the aux. I'm not suggesting ANY particular mode of operation . . . yet. DJ has proposed an architecture for which he requested a considered critical review. My input to this discussion goes toward understanding the rationale for each proposed feature that states, "when this happens, do this." At the same time, there is idea that alternator-only ops MIGHT be a good thing to review. Our current paradigm is rooted in the 1960's. The drill for crafting any system is to do the FMEA and then add/adjust features to minimize workloads and risks for the catalog of failures. Without such debate, we can only assess DJ's efforts from the standpoint of being a work of art or a photograph that is pleasant to look at . . . but of unknown value for a pilot that is wrestling with what could become a bad day in the cockpit. Bob . . . ________________________________ Message 3 _____________________________________ Time: 06:19:35 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? At 07:16 PM 1/6/2014, you wrote: > >Attached is one more recipe to help fill the 1000 page cookbook of >electrical architectures. :-) >To keep it simple, this schematic has only one bus which is fed from >both ends. The failure of any one wire or terminal or switch or >relay will not interrupt power to the bus. In the event of low >voltage, the pilot should shut off master switch #1. Doing so will >shut off power to the alternator field and master contactor coil, >thus conserving battery energy. It is up to the pilot to shut off >any other unnecessary loads. > Although this architecture is intended for a simple aircraft, the > single bus could supply power to an IFR instrument panel or to an > electrically dependent engine without danger of power loss due to > the failure of any one component. >Joe > >-------- >Joe Gores What you have offered my friend is certainly appropriate to say Figure Z-0 . . . a base line from which our systems have evolved since the first battery/ generator system was installed in an airplane. A boat-load of airplanes were successfully flown for millions of hours with this architecture which was unchanged until that pesky germanium transistor showed up for work and scared the pants off of too many system integrators who were happy with the status quo . . . the avionics master switch was born and things took off from there. It has evolved from there in many ways . . . some good . . . some not so good. But your suggestion is an excellent reminder of the idea that the best systems are crafted on a solid foundation that's 99% golden . . . adding only those features which address a tiny but risky fraction of the rest. Thanks! Bob . . . ________________________________ Message 4 _____________________________________ Time: 07:02:41 AM PST US Subject: Re: AeroElectric-List: Proposed new Z diagram? From: Dj Merrill On 01/08/2014 09:12 AM, Robert L. Nuckolls, III wrote: > The drill for crafting any system is to do the FMEA > and then add/adjust features to minimize workloads > and risks for the catalog of failures. > > Without such debate, we can only assess DJ's > efforts from the standpoint of being a work of > art or a photograph that is pleasant to look at . . . > but of unknown value for a pilot that is wrestling > with what could become a bad day in the cockpit. I apologize for not getting back to you on this and your other questions. This thing called "work" keeps getting in the way... :-) I will work on refining and clarifying my "feature" list and we can definitely discuss! :-) -Dj -- Dj Merrill - N1JOV - VP EAA Chapter 87 Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/ Glastar Flyer N866RH - http://deej.net/glastar/ ________________________________ Message 5 _____________________________________ Time: 08:58:08 AM PST US Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? From: Dj Merrill Bob, I think I am getting a glimmer of understanding of the underlying message you've been trying to communicate. I've been looking at this as a top-down approach, and I presented a draft in roughly step 3 of my design process and you've been asking about things back in step 1 that I've attempted to communicate, but have failed to do so successfully. You've also been asking about things in step 5, but we aren't there yet... :-) In rough terms, my "steps" are along the lines of: 1) List features and design goals. 2) Draft a circuit to reflect step 1. Note this is to illustrate a functional representation, and is not intended as a implementation diagram, thus specific values for components are not indicated at this time. 3) Review the circuit and verify functionality, checking for undesired behaviour, etc. (This is where I submitted my first post to the mailing list asking for peer review) 4) Spec each individual load and determine the appropriate location for each load in the circuit. Examples would be to finalize the list of which devices would be on the redundant bus, which would be on the main bus, etc. 5) Fill in specific values for components in the circuit diagram and draft an implementation diagram. 6) Review, verify, finalize. 7) Build the circuit and test, test, test. Here is my list of features and design goals: 1) There are devices that are considered critical to the safe operation of the aircraft. These devices should be able to draw power from two completely independent power buses and battery sources. This shall be known as the "redundant" bus. 2) When everything is on, devices on the redundant bus should be able to automatically draw power from either source, with no user intervention required. Ie, if one of the bus/batteries fails or is turned off, the devices on the redundant bus will remain powered on using the other source. 3) Bonus feature if alternator-only mode can be optionally supported. 4) Minimize "always-hot" wires. 5) No parasitic loads on the battery when everything is "off" (ie, clocks, etc.). 6) Each battery and associated bus should be able to be switched "off" and isolated from the rest of the circuit. 7) With special regard to the engine ignition, the ability to switch off independently of the other devices for pre-flight equivalent of "mag checks". Notes: The EFIS has three built-in diode isolated power inputs. This implies that it can be wired directly to the primary and secondary power buses directly using two of those inputs. Devices having only one power input and that are considered critical are wired to the redundant bus. Other non-critical devices will be wired to the primary bus. The aircraft will initially have one mag and one Electronic Ignition (EI). Eventually the second mag will likely be replaced with a second Electronic Ignition. Based on discussions that we've had so far on the list, I've already realized a change to be made from my initial drawing with regards to how the ECU is connected. There will be one switch for the mag, and one switch for the EI (versus the two switches for the single EI as shown currently). When the mag is swapped for the second EI, the switch will be swapped as well, leaving one switch for each EI, allowing them to be switched on and off independently. Physical layout: My panel is laid out such that the engine switches are separate from the rest. The three will be laid out as Mag (or 1st EI), 2nd EI, Starter. Electrical would be Primary Power, Alternator, Secondary Power, followed by the switches for the lights, etc. Operations: Normal operations are Primary, Alternator, and Secondary switches in the on position before engine start, and until engine shutdown. In the event of "smoke", Primary and Alternator would be turned off by hitting the two leftmost switches. This cuts power to all but the flight critical devices and has the highest chance of cutting power to whatever is "smoking". If "smoke" continues, turn on Primary power and turn off Secondary. If "smoke" still continues, get on the ground ASAP - one or the other power bus must remain on to power the engine and EFIS. Note there is a good argument to be made to replace the two separate Alternator and Primary power switches with a combined three position switch. This would reduce the total DC power switch count to 2, and slightly reduce operations complexity while only giving up alternator-only mode, which has dubious value in a two redundant bus arrangement. After further thought, I am going to make this change in my diagram. -Dj -- Dj Merrill - N1JOV - VP EAA Chapter 87 Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/ Glastar Flyer N866RH - http://deej.net/glastar/ ________________________________ Message 6 _____________________________________ Time: 09:07:15 AM PST US From: "Roger & Jean" Subject: AeroElectric-List: DIY Marker beacon antenna I have a wooden airplane in which I will be installing a Marker beacon receiver. My question is: Is it relatively simple to fabricate an antenna, or should I consider purchasing one? I assume it can be put on the inside of the airframe without a significant loss of signal strength. Roger ________________________________ Message 7 _____________________________________ Time: 10:08:16 AM PST US From: "R. curtis" Subject: Re: AeroElectric-List: DIY Marker beacon antenna > I have a wooden airplane in which I will be installing a Marker beacon > receiver. > > My question is: Is it relatively simple to fabricate an antenna, or > should I consider purchasing one? > > I assume it can be put on the inside of the airframe without a significant > loss of signal strength. After posting the above, I searched the archives and found lots of info to answer my question. Looks like I will run a coax to a convenient place and then a 40" piece of wire for the antenna, or just strip the braid off the last 40" of the coax and attach it inside the fuselage. Marker beacons will most likely disappear in the near future anyway. Just thought that since I already have the receiver, there is no reason not to put it to use. Roger -- Do you have a slow PC? Try a Free scan http://www.spamfighter.com/SLOW-PCfighter?cid=sigen ________________________________ Message 8 _____________________________________ Time: 10:21:02 AM PST US Subject: AeroElectric-List: Thoughts on a few electrical system configurations? From: "digidocs" I'm nearing the point in my RV-10 build where I need to make some decisions about the electrical system architecture. Also, like any good engineer, I've got a serious case of analysis paralysis going. In an effort to help clear the logjam, would the list share its collective thoughts? Background - I fly in IMC fairly regularly. - The engine doesn't require power to keep running, but the attitude instruments are all electrically powered. Thus keeping at least some power running is important. (i.e.: AI, GPS, COM) - The planned avionics configuration is such that in a split bus design, one set/bus of units could be depowered without loss of overall functionality. (i.e.: EFIS, GPS1, COM1 on Bus A; AI, GPS2, COM2 on Bus B) - Any LiFePO4 batteries mounted firewall forward in stainless steel enclosures for fire containment (included in weight estimates). System objectives - Provide 4.5A of power for at least 4 hours in the event of any component failure (unless we can point to a *very* established track record of performance for that component) - Minimize weight - Minimize complexity and component count Configuration options and my thoughts: (weights given are nominal relative to configuration 1) 1. 60A alternator, 27Ah lead acid battery, e-bus. +0 lbs. Standard configuration on this type of aircraft. According to Bob, complete battery failure is very rare. Even fairly degraded battery has capacity to provide sufficient reserve power. E-bus protects against wiring faults. Simple architecture is a plus. Configuration is (relatively) heavy. 2. 60A alternator, 8A alternator, 17Ah lead acid battery, e-bus. -9 lbs. Addition of backup alternator allows battery to be reduced in size, saves some weight. 3. 60A alternator, 12Ah LiFePO4 primary battery, 12Ah LiFePO4 backup battery, split bus. -18lbs. Alternator charges primary battery and, through diode, secondary battery. Split bus design because LiFePO4 batteries have low reliability compared to lead acid. Cost/availability limits backup battery to 12Ah which falls short of endurance requirement, may be possible to reduce power consumption. Relatively simple architecture. Lightest configuration. 4. 60A alternator, 8A alternator, 12Ah LiFePO4 primary battery, 2Ah lead acid secondary battery, split bus. -17lbs. 60A alternator + 12Ah LiFePO4 power Bus A. 8A alternator + 2Ah lead acid power Bus B. Busses are not interconnected. May be safe to mount 2Ah lead acid under panel to reduce firewall penetrations and wiring complexity. Dual alternator, dual battery, split bus provides high availability and unlimited endurance. Medium/high complexity. Relatively light. 5. Same as configuration 4, except with 4Ah LiFePO4 secondary battery. -16lbs. Presented in case there are issues with using/charging such small lead acid batteries with 8A alternator. Thanks for your thoughts, David Read this topic online here: http://forums.matronics.com/viewtopic.php?p=416700#416700 ________________________________ Message 9 _____________________________________ Time: 10:52:51 AM PST US Subject: Re: AeroElectric-List: DIY Marker beacon antenna From: Tim Andres Yeah I started to answer your question but I'm not an avionics expert, but have a bit of experience. So my input is a marker beacon will work off a wet noodle, you can actually just put a rubber duck or length of wire out the back and it will receive. They are rather large if made resonant, but if you want I can get you the dimension for a foil antenna if that will work. And your right, already an approach certified GPS will serve for those approaches that use a MB for a fix. Tim > On Jan 8, 2014, at 10:06 AM, "R. curtis" wrote: > > >> I have a wooden airplane in which I will be installing a Marker beacon receiver. >> >> My question is: Is it relatively simple to fabricate an antenna, or should I consider purchasing one? >> >> I assume it can be put on the inside of the airframe without a significant loss of signal strength. > > > After posting the above, I searched the archives and found lots of info > to answer my question. > > Looks like I will run a coax to a convenient place and then a 40" > piece of wire for the antenna, or just strip the braid off the last 40" > of the coax and attach it inside the fuselage. > > Marker beacons will most likely disappear in the near future anyway. > Just thought that since I already have the receiver, there is no reason > not to put it to use. > > Roger > > -- > > Do you have a slow PC? Try a Free scan http://www.spamfighter.com/SLOW-PCfighter?cid=sigen > > > > > > ________________________________ Message 10 ____________________________________ Time: 11:54:33 AM PST US Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? From: Dj Merrill Updated "Z-redundant-B" diagram at http://deej.net/glastar/pics/electrical/Z-redundant-B.jpg Changes: Removed alternator-only operation by combining the separate Alt and Primary bus switches into a single three position switch (Off, Bat, Bat+Alt). Reduced operational complexity by removing separate Alt switch. Now has 2 DC power switches (Primary/Alt and Secondary) versus 3. In the event of "smoke", turn the left most switch (Primary/Alt) off. This cuts power to all but the flight critical devices and has the highest chance of cutting power to whatever is "smoking". Reflects two EI ECUs with independent switching to allow pre-flight equivalent of "mag checks" -Dj -- Dj Merrill - N1JOV - VP EAA Chapter 87 Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/ Glastar Flyer N866RH - http://deej.net/glastar/ ________________________________ Message 11 ____________________________________ Time: 11:55:20 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: DIY Marker beacon antenna Good Afternoon Tim, If I may be so bold, are you sure you wish to go to the trouble of installing a Marker Beacon receiver and an Antenna? The Marker Beacon is no longer a required piece of equipment for an ILS approach. There are a few marker beacons that are still used as step down fixes for a few Non Precision Approaches, but they are disappearing rapidly. A very few Category II and Category III approaches are still using them, but that is about it. Those that are still in service are rapidly being replaced with other style fixes. I would imagine that if you are planning IFR flight, you will have an IFR approved GPS installed. I know of no marker beacon sites other than the ones for Category II and II that are not also a designated waypoint. For those, the GPS can be used in lieu of the Marker Beacon. No big deal, but you could save fraction of an ounce or so and little bit of labor by not installing the Marker Beacon at all. Happy Skies, Old Bob Do Not Archive In a message dated 1/8/2014 1:20:07 P.M. Central Standard Time, tim2542@sbcglobal.net writes: --> AeroElectric-List message posted by: Tim Andres Yeah I started to answer your question but I'm not an avionics expert, but have a bit of experience. So my input is a marker beacon will work off a wet noodle, you can actually just put a rubber duck or length of wire out the back and it will receive. > ________________________________ Message 12 ____________________________________ Time: 01:40:27 PM PST US From: Bill Watson Subject: Re: AeroElectric-List: Thoughts on a few electrical system configurations? David, I'm attaching the main power distribution diagram and Fuse/Breaker diagram for my RV10 (2.3 years and 350+ hours). It is an Aeroelectric Z-14 design with (2) 17aH Odysseys, 2 alternators, and dual buses. The panel, designed around 2008, includes 3 GRT/HX EFIS with dual AHRS, a G430w, SL30, PM audio panel, and TT AP. I like the whole setup. I would be glad to answer any questions about it. Bill "the electrical and avionics design & build was the most fun part of the project" Watson On 1/8/2014 1:19 PM, digidocs wrote: > > I'm nearing the point in my RV-10 build where I need to make some decisions about the electrical system architecture. Also, like any good engineer, I've got a serious case of analysis paralysis going. In an effort to help clear the logjam, would the list share its collective thoughts? > > Background > - I fly in IMC fairly regularly. > - The engine doesn't require power to keep running, but the attitude instruments are all electrically powered. Thus keeping at least some power running is important. (i.e.: AI, GPS, COM) > - The planned avionics configuration is such that in a split bus design, one set/bus of units could be depowered without loss of overall functionality. (i.e.: EFIS, GPS1, COM1 on Bus A; AI, GPS2, COM2 on Bus B) > - Any LiFePO4 batteries mounted firewall forward in stainless steel enclosures for fire containment (included in weight estimates). > > System objectives > - Provide 4.5A of power for at least 4 hours in the event of any component failure (unless we can point to a *very* established track record of performance for that component) > - Minimize weight > - Minimize complexity and component count > > Configuration options and my thoughts: > (weights given are nominal relative to configuration 1) > > 1. 60A alternator, 27Ah lead acid battery, e-bus. +0 lbs. > Standard configuration on this type of aircraft. According to Bob, complete battery failure is very rare. Even fairly degraded battery has capacity to provide sufficient reserve power. E-bus protects against wiring faults. Simple architecture is a plus. Configuration is (relatively) heavy. > > 2. 60A alternator, 8A alternator, 17Ah lead acid battery, e-bus. -9 lbs. > Addition of backup alternator allows battery to be reduced in size, saves some weight. > > 3. 60A alternator, 12Ah LiFePO4 primary battery, 12Ah LiFePO4 backup battery, split bus. -18lbs. > Alternator charges primary battery and, through diode, secondary battery. Split bus design because LiFePO4 batteries have low reliability compared to lead acid. Cost/availability limits backup battery to 12Ah which falls short of endurance requirement, may be possible to reduce power consumption. Relatively simple architecture. Lightest configuration. > > 4. 60A alternator, 8A alternator, 12Ah LiFePO4 primary battery, 2Ah lead acid secondary battery, split bus. -17lbs. > 60A alternator + 12Ah LiFePO4 power Bus A. 8A alternator + 2Ah lead acid power Bus B. Busses are not interconnected. May be safe to mount 2Ah lead acid under panel to reduce firewall penetrations and wiring complexity. Dual alternator, dual battery, split bus provides high availability and unlimited endurance. Medium/high complexity. Relatively light. > > 5. Same as configuration 4, except with 4Ah LiFePO4 secondary battery. -16lbs. > Presented in case there are issues with using/charging such small lead acid batteries with 8A alternator. > > Thanks for your thoughts, > David > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=416700#416700 > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > > ________________________________ Message 13 ____________________________________ Time: 01:57:28 PM PST US From: John W Livingston Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? How do you know that each feed going into your diodes is working? On 1/8/2014 2:53 PM, Dj Merrill wrote: > > Updated "Z-redundant-B" diagram at > > http://deej.net/glastar/pics/electrical/Z-redundant-B.jpg > > > Changes: > > Removed alternator-only operation by combining the separate Alt and > Primary bus switches into a single three position switch (Off, Bat, > Bat+Alt). > > Reduced operational complexity by removing separate Alt switch. Now has > 2 DC power switches (Primary/Alt and Secondary) versus 3. In the event > of "smoke", turn the left most switch (Primary/Alt) off. This cuts > power to all but the flight critical devices and has the highest chance > of cutting power to whatever is "smoking". > > Reflects two EI ECUs with independent switching to allow pre-flight > equivalent of "mag checks" > > > -Dj > ________________________________ Message 14 ____________________________________ Time: 02:28:45 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? > > >In rough terms, my "steps" are along the lines of: > >1) List features and design goals. Let's concentrate on this step. Take the Z-figure that comes closest to what you want. Describe which features do not address a design goal and articulate what you would do different . . . speak to the design goal either in terms of (1) a perceived risk that is mitigated by a proposed change or (2) "just because." There is no wrong motivation . . . but features in the 1-bucket can be evaluated against legacy lessons-learned and technical/economic trade-offs; stuff in the 2-bucket are not technically debatable. The feature offers functionality that is easily confirmed by looking at the diagram and no sifting of simple-ideas is needed. The change is justified "just because". This is an important exercise . . . if there are compelling revelations of shortcoming in any of the Z-figures, I'm intently interested in knowing what they are. At the same time I am reluctant to publish pretty-variations-on-a-theme that offer no demonstrable increase in utility or reduction of risk. I just received a drawing from another reader who has crafted a one-battery, two-alternator configuration loosely based on Z-12 but with a avionics master switch and some errors in functionality. My question to him will be similar, "How does Z-12 fall short of your expectations for risk management and what information do you have indicating that an avionics master is useful/ necessary?" Bob . . . ________________________________ Message 15 ____________________________________ Time: 02:38:30 PM PST US Subject: AeroElectric-List: Re: Thoughts on a few electrical system configurations? From: "Jim Berry" David, Suggest you also consider 60A primary alt. and 20A secondary alt. Set the regulator on the secondary 0.5V lower than primary regulator. I have this in my all glass RV10. After 3 years, I had a primary alt. failure due to spun bearing shorting out the winding. Bus voltage dropped 0.5V as expected; the secondary alt. picked up the slack and we completed our flight at our leisure. With 20A I can keep everything lit up indefinitely except my heated pitot and landing lights. No bus switching or load shedding necessary. Jim Berry RV-10 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=416712#416712 ________________________________ Message 16 ____________________________________ Time: 03:23:21 PM PST US From: "Roger & Jean" Subject: Re: AeroElectric-List: DIY Marker beacon antenna If I may be so bold, are you sure you wish to go to the trouble of installing a Marker Beacon receiver and an Antenna? The trouble of installing the Marker Beacon Receiver is minimal. It is already installed in my audio panel, so the only effort is to add the antenna. Bob N. in an old post said a "wet string" would work as an antenna, but I discarded that as too much trouble to keep the string moist on an approach. I am only installing it because it is there and can be activated with very little effort and could possibly be used as a backup indicator. If it wasn't there, I would NOT go out and purchase one. Roger ________________________________ Message 17 ____________________________________ Time: 05:16:18 PM PST US Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? From: Dj Merrill On 1/8/2014 4:56 PM, John W Livingston wrote: > > > How do you know that each feed going into your diodes is working? Hi John, Excellent question. The GRT HX EFIS monitors each power input, and will notify you if either of the two power inputs lose power. This will verify that the Primary and Secondary buses are getting power. I do not have any monitoring in the diagram to tell if each of the diodes is working, however, a pre-flight check turning off each of the buses before enabling the alternator could be an option. If any of the critical devices power down, one of the diodes has failed (or some other issue). -Dj -- Dj Merrill - N1JOV - VP EAA Chapter 87 Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/ Glastar Flyer N866RH - http://deej.net/glastar/ ________________________________ Message 18 ____________________________________ Time: 06:10:09 PM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? Dj, I cannot find your latest drawing.- Can you send a link or attach it? =0A=0Athx=0A=0A=0A=0A________________________________=0A From: Dj Merrill < deej@deej.net>=0ATo: aeroelectric-list@matronics.com =0ASent: Wednesday, Ja nuary 8, 2014 5:15 PM=0ASubject: Re: AeroElectric-List: Re: Proposed new Z @deej.net>=0A=0AOn 1/8/2014 4:56 PM, John W Livingston wrote:=0A> --> AeroE lectric-List message posted by: John W Livingston =0A> =0A> How do you know that each feed going into your diodes is working? =0A=0AHi John,=0A- - Excellent question.- The GRT HX EFIS monitors ea ch power input, and will notify you if either of the two power inputs lose power. This will verify that the Primary and Secondary buses are getting po wer.=0A=0A- - I do not have any monitoring in the diagram to tell if ea ch of the diodes is working, however, a pre-flight check turning off each o f the buses before enabling the alternator could be an option.- If any of the critical devices power down, one of the diodes has failed (or some oth er issue).=0A=0A-Dj=0A=0A-- Dj Merrill - N1JOV - VP EAA Chapter 87=0ASports man 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/=0AGlastar Flyer N =========================0A - - - - - - - - - - - - - -Matt Dralle, List Admi ======================= ________________________________ Message 19 ____________________________________ Time: 06:17:21 PM PST US Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? From: Dj Merrill On 1/8/2014 3:11 PM, Robert L. Nuckolls, III wrote: >> 1) List features and design goals. > > Let's concentrate on this step. Take the Z-figure > that comes closest to what you want. Describe which > features do not address a design goal and articulate > what you would do different . . . speak to the design > goal either in terms of (1) a perceived risk that is > mitigated by a proposed change or (2) "just because." The closest from the Connection is Z-19. Using my list of features/design goals from the previous email (for reference they are included at the end of this email) and comparing to Z-19: 1) For avionics, Z-19 offers power from two separate batteries, but it does not offer it from two independent power buses. However, it DOES have both of these features in the engine section of the circuit. (Because if we can do it with the critical EI, it makes sense to also do it with other equally critical devices. Non-critical devices in Z-redundant-B are on the Primary bus just like Z-19) 2) Z-19 offers this feature with regards to the batteries. 3) No alternator-only mode, but since I've also removed this from Z-redundant-B this is a null. 4) Z-19 does not minimize "always hot" wiring. (Because I don't like it, and it is easy to create a circuit that does minimize "always hot" wiring. I have nothing in my plane that requires "always hot" power other than the contactors.) 5) Z-19 has parasitic loads. (Because I don't like my battery being drained between flights, and I have nothing in the plane that requires a constant power source. The GRT EFIS will sync its time via the GPS signal after power-up.) 6) Z-19 does not offer this feature. (This is a cross between "just because I want to" and safety. In general bus wiring is "safe", with the common cause of failure being installation error as we've discussed on the list. I'm not perfect, and could inadvertently crimp a bad connection or make a bad solder joint. Additionally, being able to switch off and isolate the two separate buses allows me to easily turn off all non-critical devices with a single switch if there are issues in flight) 7) As written, Z-19 supports a single EI which can be turned off, but requires modification to support two EIs that can be turned off independently. (This is a safety feature to ensure both ignitions are working correctly during the pre-flight checks) What I would do different (ie, what I did) was take the features that I liked from the Z-19 diagram and use it as a basis to create Z-redundant-B. You can see many of the features of Z-19 in the Z-redundant diagram, with emphasis on the redundant engine bus concept in Z-19 extended to support flight critical devices. As an exercise, let's flip this around. Suppose hypothetically Z-redundant-B had been around for awhile, and someone proposed Z-19. Why would you choose to use Z-19 over Z-redundant-B? What features/design goals exist in Z-19 that you desire compared to Z-redundant-B? :-) -Dj > Here is my list of features and design goals: > > 1) There are devices that are considered critical to the safe operation > of the aircraft. These devices should be able to draw power from two > completely independent power buses and battery sources. This shall be > known as the "redundant" bus. > > 2) When everything is on, devices on the redundant bus should be able to > automatically draw power from either source, with no user intervention > required. Ie, if one of the bus/batteries fails or is turned off, the > devices on the redundant bus will remain powered on using the other source. > > 3) Bonus feature if alternator-only mode can be optionally supported. > > 4) Minimize "always-hot" wires. > > 5) No parasitic loads on the battery when everything is "off" (ie, > clocks, etc.). > > 6) Each battery and associated bus should be able to be switched "off" > and isolated from the rest of the circuit. > > 7) With special regard to the engine ignition, the ability to switch off > independently of the other devices for pre-flight equivalent of "mag > checks". -- Dj Merrill - N1JOV - VP EAA Chapter 87 Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/ Glastar Flyer N866RH - http://deej.net/glastar/ ________________________________ Message 20 ____________________________________ Time: 06:18:41 PM PST US Subject: Re: AeroElectric-List: Re: Proposed new Z diagram? From: Dj Merrill On 1/8/2014 9:09 PM, Jeff Luckey wrote: > Dj, I cannot find your latest drawing. Can you send a link or attach it? > > Hi Jeff, It can be found at: http://deej.net/glastar/pics/electrical/Z-redundant-B.jpg -Dj -- Dj Merrill - N1JOV - VP EAA Chapter 87 Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/ Glastar Flyer N866RH - http://deej.net/glastar/ ------------------------------------------------------------------------------------- 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.