AeroElectric-List Digest Archive

Wed 06/27/12


Total Messages Posted: 10



Today's Message Index:
----------------------
 
     1. 05:11 AM - Re: Producing pdf or xps files with ExpressSCH (Scott Klemptner)
     2. 06:49 AM - Bendix Magneto Wiring (MikeDunlop)
     3. 07:05 AM - Re: Bendix Magneto Wiring (George, Neal Capt 505 TRS/DOJ)
     4. 08:01 AM - Re: Re: Producing pdf or xps files with ExpressSCH (Vern Little)
     5. 09:14 AM - Re: Re: Garmin believes in Old Wive's Tales. (Robert L. Nuckolls, III)
     6. 10:23 AM - Latching Relay Redux (Jeff Luckey)
     7. 10:45 AM - Re: What's wrong with this circuit? (Robert L. Nuckolls, III)
     8. 11:02 AM - Re: Latching Relay Redux (Robert L. Nuckolls, III)
     9. 01:02 PM - Re: Latching Relay Redux (Jeff Luckey)
    10. 01:48 PM - Re: Latching Relay Redux (Robert L. Nuckolls, III)
 
 
 


Message 1


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    Time: 05:11:26 AM PST US
    From: Scott Klemptner <bmwr606@yahoo.com>
    Subject: Re: Producing pdf or xps files with ExpressSCH
    =0A=0AVern,=0A=0Ai have been using ExpressSCH for years and it has always b ehaved this way on both XP and Vista.=0A=0Ai have never found a workaround. =0A=0A-=0AScott A Klemptner=0Abmwr606 on Yahoo IM=0A


    Message 2


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    Time: 06:49:16 AM PST US
    Subject: Bendix Magneto Wiring
    From: "MikeDunlop" <mdunlop001@aol.com>
    Having searched the forum I have found the following: ------- Is there is any significant degradation in starting performance when only one mag is hot? You betcha . . . most engines come with only one impulse coupled mag. Unless both mags are impulse coupled, you need to add a jumper between the right mag's p-lead terminal and a nearby switched ground terminal on the key-type magneto switch. This has the effect of grounding out the right mag while cranking. It also has the effect of letting the right mag become "hot" with the engine still moving after an aborted cranking attempt - been known to break starter castings. ------------------------- Question is: My Long-EZ is being fitted with a O-320 B3B that has two impulse couplings! Does this mean that the jumper between the right mag's p-lead terminal and a nearby switched ground terminal on the key-type magneto switch (with Start position - Gerdes A510-2) IS NOT REQUIRED? This is all described in article at http://www.aeroelectric.com/articles/MagnetoSwitchOptions.pdf I would like to clarify this now because looking at the engine logs, it shows that the previous owner had replaced the woodruff key in the starter motor 3 times within 130 hours! This sounds as if there is a problem with kicking back on startup. BTW the engine has now been zero timed and the mags will now be overhauled. MikeD (U.K.) Read this topic online here: http://forums.matronics.com/viewtopic.php?p=376706#376706


    Message 3


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    Time: 07:05:19 AM PST US
    Subject: Bendix Magneto Wiring
    From: "George, Neal Capt 505 TRS/DOJ" <Neal.George@hurlburt.af.mil>
    Mike - If both mags are fitted with impulse couplings, and both function correctly, you may remove the jumper. neal -----Original Message----- Question is: My Long-EZ is being fitted with a O-320 B3B that has two impulse couplings! Does this mean that the jumper between the right mag's p-lead terminal and a nearby switched ground terminal on the key-type magneto switch (with Start position - Gerdes A510-2) IS NOT REQUIRED? This is all described in article at http://www.aeroelectric.com/articles/MagnetoSwitchOptions.pdf I would like to clarify this now because looking at the engine logs, it shows that the previous owner had replaced the woodruff key in the starter motor 3 times within 130 hours! This sounds as if there is a problem with kicking back on startup. BTW the engine has now been zero timed and the mags will now be overhauled. MikeD (U.K.)


    Message 4


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    Time: 08:01:03 AM PST US
    From: "Vern Little" <sprocket@vx-aviation.com>
    Subject: Re: Producing pdf or xps files with ExpressSCH
    Thanks for the confirmation, Scott. =98Express=99 has been consistently denying that they have a problem. As soon as I said that I threatened to post it on internet forums, they said that they would have an engineer look at it. Sounds like they follow the Microsoft support model (not a compliment). If you are up to it, an email to =98Express=99 describing your problem would go a long way... they said that they had never had anyone report this problem before, therefore I must be wrong (what an attitude!). My response to them was... =9CI=99m not wrong, just the first=9D. Thanks for your support. Vern From: Scott Klemptner Sent: Wednesday, June 27, 2012 5:09 AM Subject: AeroElectric-List: Re: Producing pdf or xps files with ExpressSCH Vern, i have been using ExpressSCH for years and it has always behaved this way on both XP and Vista. i have never found a workaround. Scott A Klemptner bmwr606 on Yahoo IM No virus found in this message. Checked by AVG - www.avg.com 06/26/12


    Message 5


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    Time: 09:14:38 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Garmin believes in Old Wive's Tales.
    At 12:01 AM 6/27/2012, you wrote: I just find this whole "don't dare turn it on before the engine is started" argument a little crazy. Those who have flown the B767 and similar vintage big metal things will be familiar with the significant CLUNK as engine generators come online and transfer power, causing various lights and screens to blank, flicker and carry on spectacularly. Or other effects when the APU generator comes online and takes over from battery power. Similarly, there are dozens of potentially 'sensitive' electro-whizzies firmly attached to the various busses on most aircraft with DC power system. My first such product was a pitch trim speed controller and runaway monitor for the most of the fleet of Lears. It was stuffed full of C-mos devices. Had we asked for procedures and systems to 'shut it off during cranking' . . . the product would never have made it to the production line. Yet the 20+ year old comm radios and nav systems made by Collins, Honeywell, Garmin, etc still survive these power transients, spikes, and surges. Excactly the same goes for other large aircraft I've flown. Radios and nav gear were regularly switched on, as a matter of necessity, before engine start. In almost 30 years of flying these things, I've never experience an avionics failure due to power transients when engine-driven power sources have come online and assumed the load! Exactly . . . and indeed radios much older. Don't know about the heavier iron but I was working at Cessna's single-engine facility when the Avionics Master Switch was birthed. We were indeed 'killing' a goodly number of brand new 300 series radios that sported the latest 'transistorized' audio systems and power supplies. It seemed that radios which worked when the airplane was parked in the finished goods patch didn't work the next time the airplane was started. It was 'assumed' that spikes from the starter were killing transistors. The AMS seemed like a quick and easy solution to isolating all radios from those presumed risks. In retrospect, I've deduced that it wasn't spikes that killed radios but 'brown out' transients experienced during cranking of a new, tight engine on a battery that might never have been fully topped off and had been setting on the ramp for 30-60 days. Those new, relatively fragile, germanium PNP power transistors were coming out of saturation and going into second breakdown under low voltage conditions. It was some years later that the DO-160 tests for brown out conditions were expanded . . . combined with more robust silicon transistors and designs by engineers who were good students of lessons-learned and were doing a better job. This morbid fear, bordering on complete paranoia, of avionics being on before engine start in the small-plane world is quite new to me! Agreed. But we planted the weeds back about 1965 and every flight instructor since has watered and fertilized those weeds dutifully for the 50 years hence. What was once a misinterpretation of cause and effect out of ignorance morphed into a full blown superstition. I too was once a believer but a few years after that experience at Cessna as a tech writer, I had a responsibility to understand and apply DO-160 requirements to my work product. The task turned out to be a real superstition-killer. Bob . . .


    Message 6


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    Time: 10:23:01 AM PST US
    From: "Jeff Luckey" <JLuckey@pacbell.net>
    Subject: Latching Relay Redux
    Back in 2011 there was some discussion of new latching-type relay/contactors that might be suitable for use as master relays. I remember at the time looking at the spec sheets & pricing of some of those devices and they seemed available & reasonably priced. I google search earlier this week failed to turn-up any devices that were reasonably priced and they seemed to have huge lead times. I want to consider using such a device but if they are difficult to get, I won't bother. Does anyone have a source(s) for such a device? TIA Jeff Luckey


    Message 7


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    Time: 10:45:37 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: What's wrong with this circuit?
    At 10:30 PM 6/26/2012, you wrote: I dont think Im totally convinced of the benefit of multiple busses, main & essential. In my airplane almost everything is essential (except perhaps lighting & a few accessories). My list of essential stuff: Electronic Ignition, fuel pump, regulator, EFIS, at least one nav/com, transponder. Everything else is either not used frequently (like pitot heat) or has very minimal draw where a minute or two delay in turning-off the item is not significant. Actually, it's not a 'essential bus' but an 'endurance bus'. It's a means by which one can reduce loads on a battery to the useful necessities for continued flight in the en route mode. The idea is to design an electrical system with endurance equal or greater than fuel aboard. This concept goes to Plan-B for dealing with failure of the least reliable energy source on the airplane . . . the alternator. Suggest you review the chapter on system reliability and List discussions on the philosophy and utility of the E-bus . . . Your 'concerns' are significant but may I suggest that many are of such low risk as to be outside the sphere of thought for designing your system? The hapless Mr. Lloyd may have installed every back-up-to-backup system in his airplane but all went for naught when wires pulled out of terminal. A search of FAA Service Difficulty Reports and NTSB accident reports will show that very few accidents were precipitated or exacerbated by electrical system failures. Those accidents that DID have an electrical system component would have been greatly mitigated by a combination of thoughtful architecture, good preventative maintenance (don't run batteries 'til they die) and pilot understanding of how the system worked. The prime directives for this List are "thougtful architecture that goes to comfortable tolerance of high risk failures", "understanding based on simple ideas in physics, processes and materials" and the study of "lessons learned from the experiences of others". With the single main bus that is essentially wired like a UPS (uninterruptible power supply) it seems simpler from an operational standpoint. Simpler for the mitigation what failure for which there is a demonstrably significant risk? Not to confuse automatic w/ unknown In this scenario, the system would produce a Low Batt B Volts alarm. (and a quick look at the Batt B voltmeter would indicate not only low but zero). But what is the risk for "zero volts" on a bus and what elements make up the constellation of events that might produce that event. Is it not better to first reduce those risks by changes in design, process or materials? After the ingredients that go into your proposed recipe for success are carefully combed, only then do you exercise tools necessary to craft a Plan-B for the failure that might put the mission (or hygene in your shorts) at risk. The goal is to comfortably assert that "my airplane is exceedingly unlikely to suffer an electrical emergency. It may suffer many failures of components for which I will suffer the expense of maintenance . . . but any and all will be no-sweat events." Un-authorized arc welding (while airborne), very scary! Scary to contemplate but in reality, so 'gentle' that it took many flight hours for the effects to achieve the interesting conclusion. The fact that there was a Plan-B in the pilots hip pocket paired to other features of the airplane's architecture turned a 'scary' contemplation into a 'no sweat' event. Bob . . .


    Message 8


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    Time: 11:02:48 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Latching Relay Redux
    At 12:21 PM 6/27/2012, you wrote: Back in 2011 there was some discussion of new latching-type relay/contactors that might be suitable for use as master relays. I remember at the time looking at the spec sheets & pricing of some of those devices and they seemed available & reasonably priced. I google search earlier this week failed to turn-up any devices that were reasonably priced and they seemed to have huge lead times. I want to consider using such a device but if they are difficult to get, I won't bother. Does anyone have a source(s) for such a device? If your design incorporates this, or any other uniquely crafted product, you're presented with both 'spares' and 'unconventional operations' issues. If the design goal is to reduced energy consumption in the battery contactor, you could craft a duty-cycle controller that drops the contactor excitation to about 1/2 say 1 second after you energize it. More than enough to keep it closed yet drops heating (energy consuption) by 75% or so. Then you can use ANY contactor in the constellation of similar devices while. What's more, with a alternate feed path to an E-bus, risks to mission for failure of your energy conservation device are covered by the same Plan-B that covers main alternator failure. The airplane's controls are consistent with legacy philosophies and no new spares issues are created. Bob . . .


    Message 9


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    Time: 01:02:49 PM PST US
    From: "Jeff Luckey" <JLuckey@pacbell.net>
    Subject: Latching Relay Redux
    Bob, All good points, many of which have been discussed on this forum. I'm currently doing a more academic analysis (you know, when you are stuck in traffic) as to how such devices might improve a system design (if at all) but, if they are difficult to obtain then I think the point is moot. BTW - a "pull & hold" circuit seems to me to be a non-starter - putting a bunch of 'exotic' circuitry in the critical path of the coil circuit to accomplish such a trivial task seems to me to be counter-productive. If you are counting milliamps then your system probably has bigger problems. -Jeff -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Wednesday, June 27, 2012 11:02 Subject: Re: AeroElectric-List: Latching Relay Redux <nuckolls.bob@aeroelectric.com> At 12:21 PM 6/27/2012, you wrote: Back in 2011 there was some discussion of new latching-type relay/contactors that might be suitable for use as master relays. I remember at the time looking at the spec sheets & pricing of some of those devices and they seemed available & reasonably priced. I google search earlier this week failed to turn-up any devices that were reasonably priced and they seemed to have huge lead times. I want to consider using such a device but if they are difficult to get, I won't bother. Does anyone have a source(s) for such a device? If your design incorporates this, or any other uniquely crafted product, you're presented with both 'spares' and 'unconventional operations' issues. If the design goal is to reduced energy consumption in the battery contactor, you could craft a duty-cycle controller that drops the contactor excitation to about 1/2 say 1 second after you energize it. More than enough to keep it closed yet drops heating (energy consuption) by 75% or so. Then you can use ANY contactor in the constellation of similar devices while. What's more, with a alternate feed path to an E-bus, risks to mission for failure of your energy conservation device are covered by the same Plan-B that covers main alternator failure. The airplane's controls are consistent with legacy philosophies and no new spares issues are created. Bob . . . ----- No virus found in this message. Checked by AVG - www.avg.com


    Message 10


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    Time: 01:48:33 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Latching Relay Redux
    >BTW - a "pull & hold" circuit seems to me to be a non-starter - putting a >bunch of 'exotic' circuitry in the critical path of the coil circuit to >accomplish such a trivial task seems to me to be counter-productive. If you >are counting milliamps then your system probably has bigger problems. That philosophy is core to this product from Tyco http://www.aeroelectric.com/Pictures/Contactors/Kilovac_EV200_c which not only offers a sealed atmosphere environment for better high voltage handling but an after-engagement duty-cycle managed for reduced power consumption. But it's about a $135 device as I recall. One of the drivers for installation of the E-bus was to eliminate the 0.7A draw of a battery contactor during alternator-out operations. That much current would run several radios . . . but might seriously impact a design goal for battery-only endurance to exceed fuel endurance. Trivial task? It's a matter of degree . . . Exotic? About $6 worth of Radio Shack parts will do it and it doesn't increase risks. But if one has a Rotax 18A or SD-8 excited airplane the wasted watts become more critical than when you've got 60A alternator with 40 to burn. So one could choose to achieve similar performance with a plain vanilla contactor and DIY duty-cycle management. Hardware capable of very fancy footwork is becoming less expensive while consuming less power. The things one could put in a 25 year-old VariEz lit up with an SD-8 were very limited . . . not so much today. It's all inter-related and as mentioned earlier, related to mission, hardware, full up vs. endurance loads, battery sizes and PM protocols. So if latching battery contactor is more a attractive than a duty-cycle managed device, you are ultimately responsible for the formulation of design goals and techniques used to meet them. The basket of bits-and-pieces with which the big picture is painted is huge . . . Bob . . .




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