---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 02/28/10: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:14 AM - Re: How do you reliably attach wire to a solder lug switch (Robert L. Nuckolls, III) 2. 07:07 AM - Re: Circuit protection - Amps (Eric M. Jones) 3. 07:51 AM - Re: Re: Circuit protection - Amps (Kevin Horton) 4. 08:24 AM - Re: Re: Circuit protection - Amps (ROGER & JEAN CURTIS) 5. 08:59 AM - e-bus diode (tomcostanza) 6. 09:32 AM - Re: How do you reliably attach wire to a solder lug switch (rparigor@suffolk.lib.ny.us) 7. 10:29 AM - Z-12, Z-13 (RV7ASask) 8. 10:54 AM - Re: Re: Circuit protection - Amps (Robert L. Nuckolls, III) 9. 11:11 AM - Re: e-bus diode (Robert L. Nuckolls, III) 10. 11:46 AM - Re: Z-12, Z-13 (Robert L. Nuckolls, III) 11. 04:54 PM - Noise in Handheld Tx signal. (Lapsley R. and Sandra E. Caldwell) 12. 06:04 PM - Re: Z13/20 (Mark Richards) 13. 07:38 PM - Re: Z13/20 (Noah) 14. 07:55 PM - Questions () ________________________________ Message 1 _____________________________________ Time: 06:14:11 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: How do you reliably attach wire to a solder lug switch > My question is what can I do besides double heat shrinking lugs > and wires to decrease chance of a mechanical fatigue failure? Or is > double heat shrink with wires secured within 2" adequate? Single 1" pieces of heat shrink should be fine. We've never double-covered any similar joint in a TC aircraft that I'm aware of. What part number of switch are you using? Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:07:49 AM PST US Subject: AeroElectric-List: Re: Circuit protection - Amps From: "Eric M. Jones" Assuming the circuit protection is to protect the wire...(this could be argued but not now), let's examine some situations: There is a specification called "Intrinsically Safe" which specifies that no circuit protection at all is needed if the circuit cannot exceed (depends on other factors...) about 0.2 Amperes. Google "intrisically-safe wiring" Determining the exact limit would make a great science project for an adventurous High School student. It involves --How many Joules does it takes to set fire to gasoline vapour?....Ah my misspent youth...! But the resulting lesson here is that you can limit the current through the wire at the voltage source, perhaps the bus bar, with a suitable resistor and never see currents of >0.2A, for a variety of useful devices like LEDs, timers, clocks, sensors, indicators, memories and I suppose, some instruments. Take note that intrinsically safe wiring requires special consideration when used in bundles....and that's usually an issue in aircraft wiring. It might be true that switch-breakers are less reliable than switches. But in my airplane I will use switch-breakers instead of switches AND fuses OR breakers AND the associated wiring to connect everything together. Resettable solid state fuses also have a place, and they are perfect, if indeed, the wire is what you want to protect. Modern auto fuses are worlds better than glass-tube AGC and similar contraptions. (Does Mercedes still use those awful ceramic fuses?), but it is a dictum of technological progress that the very best old technology appears just before it becomes completely extinct. Fuses have had their day. You can't really make up a reason to have them at all. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones@charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=288600#288600 ________________________________ Message 3 _____________________________________ Time: 07:51:41 AM PST US Subject: Re: AeroElectric-List: Re: Circuit protection - Amps From: Kevin Horton On 2010-02-28, at 10:05 , Eric M. Jones wrote: > > Fuses have had their day. You can't really make up a reason to have them at all. Cost is a pretty important reason to many folks. If a technology (e.g. fuses) does an perfectly adequate job, why pay more for some other technology (switch breakers) that also does a perfectly adequate job? -- Kevin Horton RV-8 Ottawa, Canada http://www.kilohotel.com/rv8 ________________________________ Message 4 _____________________________________ Time: 08:24:22 AM PST US From: "ROGER & JEAN CURTIS" Subject: RE: AeroElectric-List: Re: Circuit protection - Amps Fuses have had their day. You can't really make up a reason to have them at all. -------- Eric M. Jones Totally incorrect. . . . There have been several reasons, sited on this forum, for the use of fuses as opposed to breakers and other circuit protection devices. Cost, weight, availability, ease of use, are only a few of the reasons to use fuses. I do agree that they may not be for every application, but for the vast majority of OBAM aircraft circuit protection applications, they meet the needs. Roger ________________________________ Message 5 _____________________________________ Time: 08:59:41 AM PST US Subject: AeroElectric-List: e-bus diode From: "tomcostanza" Bob (et al), I'm about to wire the panel, and am wondering about the e-bus diode. In particular, I'm looking at Z-11. It appears to me that the diode only needs to be there when the main contactor is disengaged, and the e-bus alternate feed switch is closed. When operating normally, the diode could be a piece of wire. So why isn't the e-bus alternate feed switch a DPDT with one pole shorting the diode when in "normal" operation. During normal operation, would I not drop 0.6 volts across the diode? I have found empirically, that an 0.6 volt drop equals about a 10% deficit in the output of my comm transmitter (5w to 4.5w). I do realize that Bob has probably forgotten more than I'll ever know about this stuff, so am I over-thinking this? Or is there something I'm missing? Clear skies, -Tom -------- Clear Skies, Tom Costanza Read this topic online here: http://forums.matronics.com/viewtopic.php?p=288611#288611 ________________________________ Message 6 _____________________________________ Time: 09:32:31 AM PST US Subject: Re: AeroElectric-List: How do you reliably attach wire to a solder lug switch From: rparigor@suffolk.lib.ny.us Hi Bob Thx. for the reply. "What can I do besides double heat shrinking lugs and wires to decrease chance of a mechanical fatigue failure?" "> Single 1" pieces of heat shrink should be fine. > We've never double-covered any similar joint in > a TC aircraft that I'm aware of. What part number > of switch are you using?" I am usingfrom Newark C & K - T201SHCQE - Toggle Switch. Ron Parigoris ________________________________ Message 7 _____________________________________ Time: 10:29:49 AM PST US Subject: AeroElectric-List: Z-12, Z-13 From: "RV7ASask" Early on I decided to go with the Z-12 architecture but as my wiring came together I became more uncomfortable with it as I am going to be running dual Lightspeeds. The question kept coming up where should I wire the second ignition? The first one is directly on the Hot battery bus lead, i.e. straight to the battery. The second was planned on the E-Bus? Still not happy, I then decided to review the whole architecture and to change to Z-13/8. This has not been a big change other than I am running a B&C 20A Aux alternator. The system is pretty well done and I do not have a relay in place for the E-Bus Alternate feed. I still have the 1-3 switch in place as per the Z-12 and have not added a fuselink to the E-Bus Alternate feed. Do I need a relay? If so why? Do I need a fuse link when the alternate feed has a 7A fuse off the Bat Bus? Do I need a fuselink between the Aux Feed Current Limiter and the Bat Contactor? Thanks David Lamb RV7A Still wiring Read this topic online here: http://forums.matronics.com/viewtopic.php?p=288622#288622 ________________________________ Message 8 _____________________________________ Time: 10:54:54 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Circuit protection - Amps >Modern auto fuses are worlds better than glass-tube AGC and similar >contraptions. (Does Mercedes still use those awful ceramic fuses?), >but it is a dictum of technological progress that the very best old >technology appears just before it becomes completely extinct. Are you expecting fuses to become extinct? They have been around since long before Edison began to market electron-flow. The fuse catalogs are noteworthy for the absence of older products but still more noteworthy for the increase in numbers of new products. Not sure where "intrinsic safety" came from. While that too is a study in energy management under fault conditions, I'm not sure how it matters in conducting FMEA on our own design goals. Finally, whether Mercedes uses or does not use any product of any era is certainly not germane to our deliberations. But I cannot foresee how an elegantly simple, weak-link in the chain of electron flow will ever be totally replaced by panel-mounted thingys with handles on them. >Fuses have had their day. You can't really make up a reason to have >them at all. "Make up a reason"? How about a low cost-of-ownership solution for meeting design goals with an attractive outcome of FMEA. It's a certainty that switch-breakers do not figure favorably in that equation . . . nor do solid state breakers. If cost, weight, panel space, and time to install are not components of your personal design goals, so be it. But to suggest that others on the List are somehow outdated because they do not embrace your goals borders on elitism . . . don't you think? Bob . . . ________________________________ Message 9 _____________________________________ Time: 11:11:06 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: e-bus diode At 10:57 AM 2/28/2010, you wrote: > > >Bob (et al), > >I'm about to wire the panel, and am wondering about the e-bus >diode. In particular, I'm looking at Z-11. It appears to me that >the diode only needs to be there when the main contactor is >disengaged, and the e-bus alternate feed switch is closed. When >operating normally, the diode could be a piece of wire. So why >isn't the e-bus alternate feed switch a DPDT with one pole shorting >the diode when in "normal" operation. The design goal was to minimize parts count for reducing risk of mis-positioned switches during a re-configuration to battery only operations. The diode absolutely prevents back-feeding the main bus from the e-bus. > During normal operation, would I not drop 0.6 volts across the > diode? I have found empirically, that an 0.6 volt drop equals > about a 10% deficit in the output of my comm transmitter (5w to 4.5w). > >I do realize that Bob has probably forgotten more than I'll ever >know about this stuff, so am I over-thinking this? Or is there >something I'm missing? A "voltage drop" on the order of .6 to .7 volts is not significant with respect to operation of equipment on the e-bus. That tiny drop in output, while measureable, would not be noticed by anyone listening to you at the other end. Consider that the alternate feedpath to the e-bus is there to provide 10.5 to 12.5 volts to the equipment when the alternator is off line . . . 10.5 to 12.5 is all you're going to get out of a battery. Nonetheless, we reasonably expect equipment on the e-bus to function in a useful manner. When the alternator is working, the main bus is 13.8 to 14.6 volts . . . throw away 0.7 volts in the e-bus normal feed diode and you have 13.1 to 13.9 volts on the e-bus. Still higher than with battery-only operations. Bottom line is that the diode drop affects performance in no way that anyone would notice. Bob . . . ________________________________ Message 10 ____________________________________ Time: 11:46:08 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-12, Z-13 At 12:28 PM 2/28/2010, you wrote: > >Early on I decided to go with the Z-12 architecture but as my wiring >came together I became more uncomfortable with it as I am going to >be running dual Lightspeeds. > >The question kept coming up where should I wire the second ignition? >The first one is directly on the Hot battery bus lead, i.e. straight >to the battery. The second was planned on the E-Bus? Or the main bus. Keep in mind that your engine runs perfectly well on one electronic ignition. During battery only ops, I'd turn one ignition off to reduce battery loads. In the event of a VERY rare, dual failure (lost #1 ignition too) then you can still close the battery contactor and deal with what is now a more critical situation than the original plan-b. >Still not happy, I then decided to review the whole architecture and >to change to Z-13/8. This has not been a big change other than I am >running a B&C 20A Aux alternator. > >The system is pretty well done and I do not have a relay in place >for the E-Bus Alternate feed. That relay is only suggested for e-bus loads larger than 7A. But if you have a 20A s/b alternator, suggest you go with Z-12, put the #1 ignition on the battery bus, #2 ignition on the main bus. Odds are that you'll never have to configure for e-bus only ops. >I still have the 1-3 switch in place as per the Z-12 and have not >added a fuselink to the E-Bus Alternate feed. Protecting the alternate feed wire is recommended whether you have the relay or not. The only decision is to size that protection commensurate with e-bus, battery only loads. > >Do I need a relay? If so why? Do I need a fuse link when the >alternate feed has a 7A fuse off the Bat Bus? Do I need a fuselink >between the Aux Feed Current Limiter and the Bat Contactor? Suggest you research the e-bus feeder discussions in Appendix Z notes and in the matronics archives. Suggest also that you publish your power distribution diagram that speaks to features of the /8 upsizing to 20A. Bob . . . ________________________________ Message 11 ____________________________________ Time: 04:54:05 PM PST US From: "Lapsley R. and Sandra E. Caldwell" Subject: AeroElectric-List: Noise in Handheld Tx signal. We have a problem with excessive noise occurring in an ICOM A24. Receive is good. The noise only occurs in the transmitted signal while the engine is running, The noise is so bad the the voice is not understandable. If the operator is about 100 ft from the A/B with the engine running the noise is down to a level that is acceptable. Th hsndheld is completely independent of the a/c. Internal batteries and operation on the rubber duckie antenna. A headset is used. Two different A24's with different headsets exhibit the same problem. There are no avionics in the plane except for the handheld. To eliminate the possibility of interference from instruments or alternator we tested with the master off and the problem still exists. Previously the A24 was used acceptably with an open cockpit biplane, a Murphy Renegade. One possibility could be excessive gain using the external mike, but I am skeptical since it was acceptable in the biplane Any suggestions? Roger ________________________________ Message 12 ____________________________________ Time: 06:04:51 PM PST US From: "Mark Richards" Subject: Re: AeroElectric-List: Z13/20 Bob: Is it going to have 2 LR-3's or an LR-3/SB-1 combination? What's the timeframe before we get a peek? Thanks Mark ----- Original Message ----- From: Robert L. Nuckolls, III To: aeroelectric-list@matronics.com Sent: Saturday, February 27, 2010 9:36 PM Subject: Re: AeroElectric-List: Z13/20 >I don't have much experience analyzing schematics but when I look at >Z-13/20, I guess I just don't see what the issue is. Can someone >please educate me? It's clumsy . . . my associates would call it a kluge. Z-12 shows a well considered integration of the SD20 into a legacy system with an e-bus added. I'm working on a drawing that explores another approach to tying the SD-20 and a main alternator onto two batteries. Build a 13/20 if you wish. It will function as advertised. I pulled the drawing because I'm not proud of it and I'd prefer not to be associated with the system when and if it is used. Bob . . . ________________________________ Message 13 ____________________________________ Time: 07:38:56 PM PST US Subject: AeroElectric-List: Re: Z13/20 From: "Noah" Bob, I appreciate the response, but from a technical perspective, it doesn't give me much to go on. Let me try my question from a different angle. I prefer Z-13 over Z-12 because of the salient advantages it offers, namely that it is a two-layered electrical system, with (as far as I can tell), very little single point failure potential. With the aux alternator feeding the battery directly, the main contactor is removed from the list of single point failure modes requiring landing and fixing/replacing something. Additionally, a contactor failure does not take BOTH alternators essentially offline, as occurs with Z12. I believe that you yourself have said on numerous occasions that Z13 is your architecture of choice. When I take a 6000 mile trip, I don't want a main contactor failure to mean I am on the ground for an hour, a day, or a week waiting for a replacement. My mission requires that I be able to fly a couple of thousand miles home, COMFORTABLY, to replace that single failed electrical component in the comfort of my own hangar. Unless I am mistaken somehow, Z13 allows this, and Z12 does not. So the question I will ask again is, what is it about the SD-20 which makes it not compatible with Z-13, while the SD-8 IS compatible? Is it because the SD-8 is a dynamo, and needs no flash from the bus? Is it because the lower current SD-8 driven E-bus can use a backfeed switch instead of a relay? Something else? I have searched the archives extensively on this topic and have never found a direct technical response to this question, despite many builders who have asked the question in one way or another, and who require a Z-13 architecture with an up-sized auxiliary alternator and E-Bus, so that they can FLY COMFORTABLY all the way home, not just to the next airport. Z14 doesn't interest me because in my case its complexity isn't needed - all of my critical flight instruments and nav gear have internal battery backups and the additional weight and complexity is overkill IMHO. -------- Highest Regards, Noah Forden RV-7A Rhode Island Read this topic online here: http://forums.matronics.com/viewtopic.php?p=288688#288688 ________________________________ Message 14 ____________________________________ Time: 07:55:06 PM PST US From: Subject: AeroElectric-List: Questions Hi Bob and all I'm building a Glasair Super II RG powered by a Mazda Renesis Rotary using Tracy Crook's EC2 (injection and ignition) and EM3 (Engine monitoring) and using standard starter and a small 40amp modern auto. So fully reliant on 1 4v source power. I have a Radio and embedded systems background so I'm not completely ignora nt of electrons. I'm familiar with your Z-19 and have some general questions in order to wei gh risks. My questions are: 1. What are the failure modes of Aircraft Batteries? 2. What are the failure modes of auto starter motors? 3. What are the failure modes of auto alternators? I hope these questions are firstly reasonable and not naive and can be answ ered. Many thanks for having already benefited from this list. Steve Izett Perth Western Australia ________________________________ The contents of this email are confidential and intended only for the named recipients of this e-mail. If you have received this e-mail in error, you are hereby notified that any use, reproduction, disclosure or distribution or the information contained in this e-mail is prohibited. Please notify th e sender immediately and then delete/destroy the e-mail and any printed cop ies. 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