---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 11/19/10: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 0. 12:12 AM - Just A Few Days Left; Well Behind Last Year... (Matt Dralle) 1. 06:07 AM - Re: SD8 alt connection (gonzo24) 2. 01:05 PM - Re: Re: SD8 alt connection (Robert L. Nuckolls, III) 3. 01:09 PM - Re: Re: Z-13/8 Rev. R (Robert L. Nuckolls, III) 4. 01:16 PM - Re: Re: Z-13/8 Rev. R (Robert L. Nuckolls, III) 5. 04:08 PM - Re: Z13/8 Rev Q comments (Robert L. Nuckolls, III) ________________________________ Message 0 _____________________________________ Time: 12:12:39 AM PST US From: Matt Dralle Subject: AeroElectric-List: Just A Few Days Left; Well Behind Last Year... Dear Listers, There are just a few more days left of this year's List Fund Raiser. Response has been good so far, but we're well behind last year at this point. 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Matt Dralle Matronics Email List Administrator ________________________________ Message 1 _____________________________________ Time: 06:07:06 AM PST US Subject: AeroElectric-List: Re: SD8 alt connection From: "gonzo24" Bob, thank you for the reply. In reviewing the Z-13/8 schematic... since the 2awg batt and 14awg batt buss are all connecting at the same point on the batt contactor on the engine side of the firewall.... Wouldn't it be the same thing to terminate the SD-8 output lead directly to the battery buss stud inside the cabin? I ask this as all of my SD-8 power components i.e. regulator, capacitor, OV, relay are installed cabin side of the firewall (per the instructions received with these parts). Why would it be necessary to run the lead with the inline 30amp fuse back out to the batt contactor? In the event of a Primary alt failure, the SD-8 should still be excited through the 14AWG contact it has to the primary battery. Should one connect a smaller aux batt on the Batt buss as well in this case? I ask this as LSE's power diagram shows two batteris for dual ignition as well. thank you for your time. -------- RV-7a completed flown 700+ hrs sold Rv-7 under construction Read this topic online here: http://forums.matronics.com/viewtopic.php?p=320077#320077 ________________________________ Message 2 _____________________________________ Time: 01:05:12 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: SD8 alt connection At 08:03 AM 11/19/2010, you wrote: > >Bob, > >thank you for the reply. In reviewing the Z-13/8 schematic... since >the 2awg batt and 14awg batt buss are all connecting at the same >point on the batt contactor on the engine side of the >firewall.... Wouldn't it be the same thing to terminate the SD-8 >output lead directly to the battery buss stud inside the cabin? Whoops! You have an always hot fat wire coming through the firewall? >I ask this as all of my SD-8 power components i.e. regulator, >capacitor, OV, relay are installed cabin side of the firewall (per >the instructions received with these parts). Why would it be >necessary to run the lead with the inline 30amp fuse back out to the >batt contactor? In the event of a Primary alt failure, the SD-8 >should still be excited through the 14AWG contact it has to the >primary battery. Okay, you've arranged components with priorities ordered differently than suggested in the Z-figures and I understand why. I wish B&C wouldn't put those little notes in with his products suggesting that certain electro-whizzies are better off inside the cabin. Sure, connect the SD-8 to the battery bus . . . in fact, put a 30A fuse in one of the battery bus fuse-slots and use it to route power to the system. Airplane parts are airplane parts. They are selected and qualified for specific duty in locations selected first for functionality, minimum parts count, weight, and nice failure mode effects analysis. Obviously, boxes with LCD displays, push buttons and knobs NEED to go in the cabin and their tolerance for environmental extremes are relaxed because shares spaces where people sit. All other gizmos, particularly system power management parts should be happy living anywhere except perhaps bolted to an exhaust stack. The current locations for your SD-8 system parts and battery bus are now pretty much a given so you're compelled to make adjustments for how the wires are handled. >Should one connect a smaller aux batt on the Batt buss as well in >this case? I ask this as LSE's power diagram shows two batteris for >dual ignition as well. No . . . don't mix-match architectures. I've encountered several instances where the system integrator attempted to cherry-pick what appeared to be "good and wonderful" features of multiple systems with the notion that each plucking of an idea makes the whole more righteous. The whole idea behind LSE's recommendations go to increasing probability that at least one of two ignition systems will have power irrespective of MULTIPLE failures . . . and without regard to the thought processes that ago toward fabrication of a FAILURE TOLERANT system. The battery in the OBAM aircraft owned, operated and maintained by a cognizant builder is the most reliable source of energy in the airplane. It's only limitation is total stored energy traded off with how much lead, water and plastic the builder is willing to drag around. Then comes TWO, engine driven power sources capable of mitigating battery limitations. By the way, if you DO find yourself operating either battery only . . . or battery+SD8, then turn one of the ignition systems off. The engine will hardly know the difference and your electrical system loads drop by about 2 amps. B&C and LSE make recommendations based on their best wishes and understanding of the systems they sell. The AeroElecric Connection goes toward a rational approach for crafting the whole system based on ingredients that go into recipes for success going WWWwaaayyyy back . . . further than any current supplier of electro-whizzies. Understand that supplier recommendations are almost never 'wrong'. But most suppliers are not system integrators with a focus on the big picture. Note how many different Z-figures there are as opposed to how many ways the legacy T/C aircraft is wired . . . I'll have a first-hand review of a dark-n-stormy night story to share with the List where the outcome wasn't a complete disaster . . . everybody walked away. The system integrator cherry-picked whippy ideas without regard their 'fit' in the overall system. The effects of some poor decisions were expensive and linger to this day. I'll tell you all about it after the court case settles. Please don't take anything above as a harbinger of doom for what you've described. Your system's WIRING and FUNCTIONALITY are going to be just fine and will function as advertised. We're only sifting through the simple-ideas that go to very low orders of risk. >thank you for your time. You're most welcome. That's what we're all here for . . . Bob . . . ________________________________ Message 3 _____________________________________ Time: 01:09:52 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z-13/8 Rev. R At 02:26 PM 11/18/2010, you wrote: > >Bob, >I was under the impression that EMAG Air had discontinued the "E" >mag and was only making/selling the "P" mag. Just thinking that if >you're revising it, maybe worthwhile to look into that also. Interesting. Thanks for the heads-up. I note that the e-models are not priced on the website. I've not talked with those guys for awhile, I need to give them a call and catch up. Bob . . . ________________________________ Message 4 _____________________________________ Time: 01:16:25 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z-13/8 Rev. R At 11:46 AM 11/18/2010, you wrote: >Minor comments to consider: > >My local experience is that most everyone building these days, even >those on a budget, are installing engine monitors. Stand-alone low >voltage monitors are not required. Similarly, alternator load >meters and their associated shunts have been replaced by Hall effect >sensors and the engine monitor. Maybe its time to modernize the >schematic to reflect this? Just a thought... The Z-figures are not a "do it this way" document. They're an example of an ARCHITECTURE which speaks to failure tolerance for a particular combination of flight-profile-driven battery and alternator decisions. Whether or not a particular airplane is fitted with the accessories illustrated is not germane to the intent and purpose of the Z-figure. There's an endless combination of accessories that may drive sizes of busses, sizes of battery, size of alternator, sizes of wires, choices of ignition systems and yes . . . methodology for monitoring any of the ship's functions. The most important thing to consider for LV monitoring is timely, unambiguous and attention getting notification for "time to switch to plan-b". If the builder has some alternative means for accomplishing that, great. The reason for having it in the Z-figure is to simply remind the planner that SOME form of device needs to be a part of the final recipe for success. Bob . . . ________________________________ Message 5 _____________________________________ Time: 04:08:47 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z13/8 Rev Q comments At 12:15 AM 11/19/2010, you wrote: > >Bob, > >I wonder why the feed paths to the Endurance Bus are different. The >relay from the battery bus is 14 awg and fused, while the diode from >the main power bus is 16 awg and not fused. Good question. The 16AWG wires are adequate to the current carrying task assigned to power the e-bus and you'll note that they're called out as "short" wires. As "short", potentially sacrificial wires, we'd like them to fuse open as fast as practical, hence make them as small as practical. As we discovered in this experiment on the bench some time back . . . http://aeroelectric.com/Pictures/Wire/22AWG_20A.pdf . . . a 20 AMP current through a 22AWG wire didn't warm it enough to put the 150C insulation at risk. So we could probably wire the short normal feed path with 20 or even 18 AWG without 'over stressing' the the wire. An e-bus configured to the original idea calls for punching through a cloud layer at the home airport, failing an alternator, and flying comfortably to airport of intended destination battery only. This called for getting alternator-out endurance-bus loads down to 2 or 3 amps. Not an terribly difficult task in the magneto/steam-gage era. Then came electrically dependent engines and clusters of panel mounted 'stuff' that increased the size of a 'minimalist' power requirement. Okay, add the SD-8 and we've got 8-10 amps of continuous load without depleting the battery. Figure 2-3 amps of the original concept on top of that and one COULD consider an e-bus load of perhaps 13 amps. Okay, the feeders had to take a big jump in AWG. Hence the fat feeder for alternate feed path. If we're to observe the reverence for crash safety and limit always hot feeders to 7A or less, then the S704 relay gets added and the fuse sizes go up to accommodate the new definition of endurance loads. This illustrates the thinking behind the disparity between normal and alternate feed wire sizes. >Previously, I was planning to use 14 awg and * 6 inches or less wire, >without any fuses for both paths. How did you arrive at this? When the battery and main bus fuse blocks are immediately adjacent to each other, then the no-fuse, 16AWG feeders (or even smaller as described above) through the diode fits legacy design goals. But the feeder from the battery bus to the e-bus is a long conductor that classically gets either: (1) 7A or less protection for skinny feeder and no remote mini-contactor or (2) a larger feeder and contactor per Z-32. The larger 14AWG wire is appropriate for low voltage drop on longer wires good for up to 15A and rear mounted batteries. If your battery is up front, that wire could comfortably drop to 12AWG. >I have changed my drawing so both paths include fuses. Doen't hurt . . . but not necessary by legacy design goals. >Since Z13/8 highlights some new technology with E-Mags, perhaps it >makes sense to replace the Ford regulator with an electronic one that >includes overvoltage protection and low voltage annunication ? As suggested in an earlier post, you are encouraged to consider the full constellation of available accessories to put frosting on the Z-13/8 cake. I doubt that no two OBAM airplanes flying this ARCHITECTURE have the same frosting. It's my personal goal to suggest the simplest, lowest cost suite of components that get the job done. If the builder's design goals and pocket-book goes beyond those suggestions, great! 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.