---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 01/12/08: 18 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:49 AM - Re: Terminal Tool TT5000 (Bret Smith) 2. 05:41 AM - Re: Toggle switch tool (Ralph Hoover) 3. 05:57 AM - Re: Terminal Tool TT5000 (Ralph Hoover) 4. 07:00 AM - Automatic fuel pump backup switch (mtmeans) 5. 07:54 AM - Re: Automatic fuel pump backup switch (Robert L. Nuckolls, III) 6. 08:44 AM - Re: Strobe discharge pop-pop-pop (Jeff Page) 7. 09:09 AM - Re: Automatic fuel pump backup switch (Aaron Gustafson) 8. 09:17 AM - Re: Re: Strobe discharge pop-pop-pop (Robert L. Nuckolls, III) 9. 10:51 AM - Re: ELT/PLB () 10. 11:25 AM - Re: Automatic fuel pump backup switch (Dj Merrill) 11. 11:35 AM - Apppendix Z, Rev M (Robert L. Nuckolls, III) 12. 11:40 AM - Re: Fw: Europa XS with ULPower 260i engine (Robert L. Nuckolls, III) 13. 12:08 PM - Re: Re: ELT/PLB (Jon Finley) 14. 01:12 PM - Re: RV-List: Cheaper 406mhz plb alternative? (Ralph Finch) 15. 01:50 PM - Re: RV-List: Cheaper 406mhz plb alternative? () 16. 04:53 PM - Re: Fw: Europa XS with ULPower 260i engine (Gaye and Vaughn) 17. 05:24 PM - Re: Automatic fuel pump backup switch (Tim Shankland) 18. 05:51 PM - Re: Europa XS with ULPower 260i engine (OOPS!!!) (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 04:49:17 AM PST US From: "Bret Smith" Subject: RE: AeroElectric-List: Terminal Tool TT5000 There is at least one builder who has one, but I can't remember who. He said it was the "cats meow". I just can't justify paying $150.00 for the (4) fat wire crimps I need... Bret Smith RV-9A N16BL Blue Ridge, Ga www.FlightInnovations.com -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Michael D. Cencula Sent: Saturday, January 12, 2008 1:28 AM Subject: AeroElectric-List: Terminal Tool TT5000 --> Anyone used one of these: http://www.averytools.com/pc-937-80-the-terminal-tool.aspx It looks like it might be good for those heavy gauge wires. Thanks, Mike Cencula RV-7A Fuse ________________________________ Message 2 _____________________________________ Time: 05:41:29 AM PST US From: Ralph Hoover Subject: Re: AeroElectric-List: Toggle switch tool I avoided the issue all together. My switches are mounted on a u channel with thru holes drilled for anti rotation. The whole channel mounts behind the panel with just the nose of the switch bushings partially onto the back of the panel. * only 4 screws exposed * Can be dropped from behind the panel for service or panel removal * Labeled with an engraved panel from Front Panel Express "www.*frontpanel**express*.com/" * Switches can be tightened to the channel without damage to the panel -- Ralph C. Hoover RV7A hooverra at verizon dot net ________________________________ Message 3 _____________________________________ Time: 05:57:43 AM PST US From: Ralph Hoover Subject: RE: AeroElectric-List: Terminal Tool TT5000 Kool! See http://www.rv7blog.com/2007/11/04/fancy-crimper/ Looks like something that would be good in a chapter tool crib! -- Ralph C. Hoover RV7A hooverra at verizon dot net ________________________________ Message 4 _____________________________________ Time: 07:00:37 AM PST US Subject: AeroElectric-List: Automatic fuel pump backup switch From: "mtmeans" I have an auto conversion project with dual high pressure fuel pumps. The fuel pumps are plumbed in parallel with one way valves and are not happy when running together (stronger pump blocks flow of weaker), ie harmful to switch secondary on during critical flight. Reflexes being what they are during these times I am considering a fuel pressure (or other switch) that could turn on the second pump if first fails. Any suggestions. I tried to search for this exact issue and had problems. Thanks. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=157617#157617 ________________________________ Message 5 _____________________________________ Time: 07:54:49 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Automatic fuel pump backup switch At 06:58 AM 1/12/2008 -0800, you wrote: > >I have an auto conversion project with dual high pressure fuel pumps. The >fuel pumps are plumbed in parallel with one way valves and are not happy >when running together (stronger pump blocks flow of weaker), ie harmful to >switch secondary on during critical flight. Reflexes being what they are >during these times I am considering a fuel pressure (or other switch) that >could turn on the second pump if first fails. Any suggestions. I tried to >search for this exact issue and had problems. Thanks. The Eggenfellner Subaru conversion recommends the arrangement I believe you're looking for. Their recommended installation calls for a pair of pumps, either of which can run the engine through appropriate plumbing parts . . . On the electrical side, he suggests a #1, #2, Auto switch for pump selection. #1 and #2 are self explanatory. One or the other but not both. The Auto position powers the #1 pump through relaxed contacts of a relay that is energized by the closing of a low pressure switch. Once the relay is energized, contacts transition to remove power from #1 and apply power to #2 pump. At the same time, the relay is electrically latched so that it will not de-energize without some externally applied conditions (pilot actions, loss of electrical power) that cause the relay to relax. I'll be incorporating this feature into an Eggenfellner version of Z-19 but before that drawing comes out, I'll refer you to their webite publications at: http://eggenfellneraircraft.com/ESeriesInstallationGuide.pdf Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 6 _____________________________________ Time: 08:44:55 AM PST US From: Jeff Page Subject: AeroElectric-List: Re: Strobe discharge pop-pop-pop Ralph, I had this same problem with the strobes in my Cessna 172. I solved it by inserting a 1N4002 diode in the power feed to my intercom and putting a 2200uF/35V capacitor between power and ground on the intercom side. Unfortunately this was after rewiring all the intercom wires which had been shoddily installed and incorrectly grounded at both ends. Parts were what I had at hand. It is an easy thing to for you to try. I also found the problem was much more noticable when testing on the ground when the alternator was not running to boost the voltage than when flying. Jeff Page Dream Aircraft Tundra #10 > From: "Ralph E. Capen" > Subject: AeroElectric-List: Strobe discharge pop-pop-pop > > I'm doing some system testing and I can hear a very slight pop each time my > strobes discharge through my headset. It doesn't break the squelch or > prevent me from hearing the radios - or stereo for that matter. No whining > on the charge cycles and I gotta listen carefully to catch the pop - but it's > there. > > Is this strictly due to the high-voltage discharge in a 12V system? > Is there something I can due to get rid of this? Or should I take gladness > that it's faint, doesn't interfere, it's as good as it gets, have a coke and > a smile and.......? > > Ralph ________________________________ Message 7 _____________________________________ Time: 09:09:49 AM PST US From: "Aaron Gustafson" Subject: Re: AeroElectric-List: Automatic fuel pump backup switch ----- Original Message ----- From: "mtmeans" Sent: Saturday, January 12, 2008 8:58 AM Subject: AeroElectric-List: Automatic fuel pump backup switch >>>> The fuel pumps are plumbed in parallel with one way valves and are not >>>> happy when running together (stronger pump blocks flow of weaker) But isn't that the same as happens when the system is not using any fuel except for what may return if there is a return line. I have the same system with low pressure (6#) pumps and carburetor. I run both pumps during all critical operations as I feel there is no time for decisions close to the ground even if there was time to get pressure. Aaron Gustafson Zenith 601HD ________________________________ Message 8 _____________________________________ Time: 09:17:13 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Strobe discharge pop-pop-pop At 11:25 AM 1/12/2008 -0500, you wrote: > >Ralph, > >I had this same problem with the strobes in my Cessna 172. >I solved it by inserting a 1N4002 diode in the power feed to my >intercom and putting a 2200uF/35V capacitor between power and ground >on the intercom side. >Unfortunately this was after rewiring all the intercom wires which had >been shoddily installed and incorrectly grounded at both ends. Parts >were what I had at hand. It is an easy thing to for you to try. > >I also found the problem was much more noticable when testing on the >ground when the alternator was not running to boost the voltage than >when flying. Interesting! This demonstrates that the noise is conducted and the only way that the flash-tube circuit can couple to ship's wiring is magnetic or electrostatic. Twisting of the strobe head wires under a shield takes care of both of these coupling modes except where a ground loop (something connected to airframe at fixture end of wires). As an experiment, try operating your victim system(s) from their own quiet power source . . . say a couple of 6v lantern batteries in series. Get some el-cheesos from Wal-Mart. If the noise goes away while powered only by the batteries, then it's coming in through the +14v power wires. In this case, adding the diode and capacitor as cited above is worth exploring. Alternatively, it's worth exploring how the admittedly intense flash tube noises are getting out of their normally tight confines. Bob . . . ________________________________ Message 9 _____________________________________ Time: 10:51:52 AM PST US From: Subject: AeroElectric-List: Re: ELT/PLB Good comments, I'll just add a few points. Yes a PLB is a great adjunct while the 406Mhz Regs are in limbo (not yet mandated). Heck a PLB is a great thing to have for you, your wife in kids in the car, boat, skiing, hiking. How many people get lost or stuck. (story below) PLB's are NOT ELT's PLB's advertise they have the same output power, but they don't get out as well with the small portable antenna. Besides compromises in the antenna, battery life is less. The antenna has no real ground plane. It can't meet With that said PLB's are are pretty good for the money and I want one. With PLB limitations said, if your airframe mounted ELT's antenna is crushed under the plane it will not work well either. Of course a PLB needs to be manually turned on. The PLB is good idea even if you have a 406 ELT. The 406ME Artex ELT is the only game in "low cost" units for aviation at about $1000. Others are working on units but from what I am told, the specs almost mandate a lithium Ion battery (as Aertex has) and you can forget cheap "D" cells. They don't cut it. The END IS NEAR The 243 MHz is going away, period. As many limitations as the old ELT technology had, its going to get even less effective. The 243 MHz Sats are going to stop looking (so they say). Widely advertised is the accuracy of the 406 MHz technology, almost perfect with GPS input. No guarantees in life, but 406 is better. There is an aviation 406 ELT that can be removed and used with a portable antenna. The basic Artex is the 406ME ($1000), the one with the portable antenna is 406ME/P. They look similar, but I'm told they case is different (probably a ground plane). The antenna folds out almost two feet. It cost about $200 or $300 more? If they could only add internal GPS but than you have another GPS antenna and the extra battery drain. Artex commercial models with GPS interface are BIG bucks. If you have a 406 MHz ELT it seems like a shame not to transmit ELT pos since the capability is there. The SAR comes right to you. Of course that is where the 121.5Mhz comes in, that is for local DF. The PLB for the military and marine use have portable capability. So may be one of these PLB might be better than general consumer types? Steve Fossett has not been found and may never be. The RV pilot that was lost over NM and TX boarder was not found for months, even with ATC radar tracking. If you want to be found or you want your family to have a body to bury, you need a working ELT. The 406Mhz is your best bet. Also the Artex 406ME does not have GPS data. For only $600-$700 you can get GPS data with a PLB. It could save your life in a car, boat or hiking. Story: There have been many cases where people get lost hiking or a person just drives off the road, survives but is not found for days. Some times they find them alive a week later off the side of the road, even though they where only 50 yards from the freeway, on their normal routes from home to work or shopping. In one tragic case the police would not pull- up the Cel Phone ping info for several days for a woman, despite the husband's request. Missing person wait period rules I guess. When they did get the Cel phone triangulation, they found the car, in gully off the side of the road, but the woman had expired. She was alive for a day or more. PLB might have saved her if she could have activated it. The police don't have to go into SAR mode for a wife that did not come home after work. I guess that is a sales pitch for ON-Star. FLY SAFE. Other wise flight following AND file detailed flight planes & fly them. George RV-7 finishing --------------------------------- Never miss a thing. Make Yahoo your homepage. ________________________________ Message 10 ____________________________________ Time: 11:25:02 AM PST US Subject: Re: AeroElectric-List: Automatic fuel pump backup switch From: Dj Merrill Robert L. Nuckolls, III wrote: > The Eggenfellner Subaru conversion recommends > the arrangement I believe you're looking for. > Their recommended installation calls for a > pair of pumps, either of which can run the engine > through appropriate plumbing parts . . . > > On the electrical side, he suggests a #1, #2, Auto > switch for pump selection. #1 and #2 are self > explanatory. One or the other but not both. The Auto > position powers the #1 pump through relaxed contacts > of a relay that is energized by the closing of a low > pressure switch. Once the relay is energized, contacts > transition to remove power from #1 and apply power to > #2 pump. At the same time, the relay is electrically > latched so that it will not de-energize without some > externally applied conditions (pilot actions, loss of > electrical power) that cause the relay to relax. > > I'll be incorporating this feature into an Eggenfellner > version of Z-19 but before that drawing comes out, I'll > refer you to their webite publications at: > > http://eggenfellneraircraft.com/ESeriesInstallationGuide.pdf > > Bob . . . Hi Bob, I'm confused. I'm pretty sure I remember from the Eggenfellner mailing list that they currently recommend both pumps on for takeoff and landing, and to turn off one for cruise. On page 51 of the PDF you reference, I don't see any of the relays or low pressure switches that you refer to. In the "green" area of the schematic, there are just two switches, one for each fuel pump, each inline with a 10A circuit breaker, that are both attached to pin #8 of the "Bus Master Switch". In the past Eggenfellner had pressure switches in their installations, but no longer recommends them due to reliability issues with the pressure switch and the added complexity of the setup. -Dj -- Dj Merrill Sportsman 2+2 Builder #7118 http://deej.net/sportsman/ "Many things that are unexplainable happen during the construction of an airplane." --Dave Prizio, 30 Aug 2005 ________________________________ Message 11 ____________________________________ Time: 11:35:07 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Apppendix Z, Rev M I've just posted an update to Appendix Z at: http://aeroelectric.com/articles/Rev11/AppZ_R11M.pdf It adds two pages to figure Z-15, grounding architectures that go into some OK/NOT-OKAY examples for grounding various equipment items in the airplane. The additional coverage goes to the goals of (1) avoiding the grounding of potential victim systems (avionics, instruments) in more than one place on an airframe that is carrying (2) significant alternator and other systems noises injected by local grounds for those antagonists. It also goes to the notion of a linear system of multiple ground points. I.e, engine (G1), forward side of firewall (G2), aft side of firewall (G3) and panel (G5) as a suite of 'single-point' grounds while accommodating a few local grounds (G4) for potential antagonists where they do not share ground returns (loops) with potential victims. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 12 ____________________________________ Time: 11:40:32 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Fw: Europa XS with ULPower 260i engine At 05:14 PM 1/8/2008 -0500, you wrote: > >I have received the following reply from the ULPower representatvie to my >question, "Why do I not need to include crowbar OV protection with this >engine?" > > >Our electronics guy sent me a diagram showing the principle of how our >type of regulator works. He says (in Dutch below) that: > >---------- >our type is a "shunt" regulator which shorts the PMG to ground when the >battery voltage increases above the nominal level so that the battery can >never be over charged and damaged. >The principle of a PMG is different to a Regulated Field Generator >(typical in cars) where the magnetic field is regulated to vary the >voltage of the generator. >A PMG acts as a constant current source and therefore may be shorted out. > >---------- >The regulator / rectifier we use is typically used on large capacity >motorbikes and our supplier says they are very robust. > >He also sent the attached schematic: > >So as I see it, the attached schematic for my airplane should be sufficient. > >Vaughn Teegarden What you've proposed will be fine. The regulator topology you cited is a carry through of the earliest PM alternator regulators. It throttles or controls alternator output to the system by putting a dead short on the alternator's stator windings during short periods where unrestrained output would boost the system voltage too much. This is a very simple approach that has been effective since day-one . . . but does have the down-side of causing the alternator to run at max output current 100% of the time whether that energy is used by the electrical system or not. Of course, if wire size and cooling considerations for the alternator are carefully addressed, this can produce a robust, reliable system. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 13 ____________________________________ Time: 12:08:44 PM PST US From: "Jon Finley" Subject: RE: AeroElectric-List: Re: ELT/PLB All, One function of a PLB that seems to have been forgotten is the tracking mode (see http://www.findmespot.com/). Assuming you go down and the PLB is destroyed, your next of kin have a very good idea of your whereabouts - much better idea than an ELT provides. Frankly, if I crash and die, I could care less if someone finds me (I know my family does not feel that way). What I desire out of my PLB is the ability to tell someone exactly where I am if I have a problem and survive. Ya - all kinds of scenario's can be debated but if you MUST have a completely fail safe solution - don't expect to get it from a $150 device. Jon Finley N314JF - Q2 - Subaru EJ-22 Legacy http://www.finleyweb.net Mid-Valley Airpark (E98), Los Lunas, NM ________________________________ Message 14 ____________________________________ Time: 01:12:27 PM PST US From: "Ralph Finch" Subject: AeroElectric-List: RE: RV-List: Cheaper 406mhz plb alternative? I attended a presentation on this device a few days ago. - It absolutely does not replace any kind of ELT on aircraft. You must still have an ELT, either 121.5 or 406 MHz. - It is a private satellite service. You don't pay the annual fee, it doesn't work for you. It seems to be an initially cheaper alternative to portable PLBs, but they then charge annual fees to make up the cheaper purchase price. Seems really designed for outdoors hikers, backpackers, sportsmen, etc. -----Original Message----- From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of Charlie England Sent: Wednesday, January 09, 2008 7:18 PM Subject: RV-List: Cheaper 406mhz plb alternative? --> RV-List message posted by: Charlie England Anyone know any details about this product? http://www.findmespot.com/explorespot/spotmessenger.aspx IF it's using the public SARSAT satellites, maybe it would still work after the 1st mandatory subscription lapses. (Still be a lot cheaper than typical PLBs with built in GPS.) Charlie ________________________________ Message 15 ____________________________________ Time: 01:50:42 PM PST US Subject: AeroElectric-List: RE: RV-List: Cheaper 406mhz plb alternative? From: Hi All, There are some poor man's versions of tracking for mobile phones that might do some of the functions outlined here. Have a look at http://www.codeproject.com/KB/mobile/FindMe.aspx It's a program that gets your GPS equipped Mobile phone to report its location in response to a SMS call. I would still have the PLB but if the family want to find you then this may be a cheap alternative using stuff you may already have. Cheers John -----Original Message----- From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of Ralph Finch Sent: Sunday, 13 January 2008 8:09 AM Subject: RE: RV-List: Cheaper 406mhz plb alternative? --> RV-List message posted by: "Ralph Finch" I attended a presentation on this device a few days ago. - It absolutely does not replace any kind of ELT on aircraft. You must still have an ELT, either 121.5 or 406 MHz. - It is a private satellite service. You don't pay the annual fee, it doesn't work for you. It seems to be an initially cheaper alternative to portable PLBs, but they then charge annual fees to make up the cheaper purchase price. Seems really designed for outdoors hikers, backpackers, sportsmen, etc. -----Original Message----- From: owner-rv-list-server@matronics.com [mailto:owner-rv-list-server@matronics.com] On Behalf Of Charlie England Sent: Wednesday, January 09, 2008 7:18 PM Subject: RV-List: Cheaper 406mhz plb alternative? --> RV-List message posted by: Charlie England Anyone know any details about this product? http://www.findmespot.com/explorespot/spotmessenger.aspx IF it's using the public SARSAT satellites, maybe it would still work after the 1st mandatory subscription lapses. (Still be a lot cheaper than typical PLBs with built in GPS.) Charlie ________________________________ Message 16 ____________________________________ Time: 04:53:28 PM PST US From: "Gaye and Vaughn" Subject: Re: AeroElectric-List: Fw: Europa XS with ULPower 260i engine Thanks Bob, I am going down to LSA show in Sebring, Florida to see the guys who make the engine. I hope it works out well for me. Vaughn Teegarden ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Saturday, January 12, 2008 2:33 PM Subject: Re: AeroElectric-List: Fw: Europa XS with ULPower 260i engine > > > At 05:14 PM 1/8/2008 -0500, you wrote: > >> >>I have received the following reply from the ULPower representatvie to my >>question, "Why do I not need to include crowbar OV protection with this >>engine?" >> >> >>Our electronics guy sent me a diagram showing the principle of how our >>type of regulator works. He says (in Dutch below) that: >> >>---------- >>our type is a "shunt" regulator which shorts the PMG to ground when the >>battery voltage increases above the nominal level so that the battery can >>never be over charged and damaged. >>The principle of a PMG is different to a Regulated Field Generator >>(typical in cars) where the magnetic field is regulated to vary the >>voltage of the generator. >>A PMG acts as a constant current source and therefore may be shorted out. >> >>---------- >>The regulator / rectifier we use is typically used on large capacity >>motorbikes and our supplier says they are very robust. >> >>He also sent the attached schematic: >> >>So as I see it, the attached schematic for my airplane should be >>sufficient. >> >>Vaughn Teegarden > > What you've proposed will be fine. The regulator > topology you cited is a carry through of the > earliest PM alternator regulators. It throttles > or controls alternator output to the system by > putting a dead short on the alternator's stator > windings during short periods where unrestrained > output would boost the system voltage too much. > > This is a very simple approach that has been > effective since day-one . . . but does have the > down-side of causing the alternator to run at > max output current 100% of the time whether that > energy is used by the electrical system or not. > Of course, if wire size and cooling considerations > for the alternator are carefully addressed, this > can produce a robust, reliable system. > > Bob . . . > > > ----------------------------------------) > ( . . . a long habit of not thinking ) > ( a thing wrong, gives it a superficial ) > ( appearance of being right . . . ) > ( ) > ( -Thomas Paine 1776- ) > ---------------------------------------- > > > ________________________________ Message 17 ____________________________________ Time: 05:24:49 PM PST US From: Tim Shankland Subject: Re: AeroElectric-List: Automatic fuel pump backup switch The way I handled this was on my 601 HD with A Stratus Suburu was to put both electric pumps is series. This will cause an addition of pressures so after the pumps I put a fuel pressure regulator adjusted to 5 psi. in this way I can run both pumps for takeoff and landing, or any other time I like and not exceed the limits of the carb. By the way one of the Fauset pumps required a by pass check valve so that either pump could operate independently. I looked into various automatic systems such as sensing the pressure and modulating one of the pumps but this was far simpler and so far with my 65 hours has been trouble free. Tim Shankland mtmeans wrote: > >I have an auto conversion project with dual high pressure fuel pumps. The fuel pumps are plumbed in parallel with one way valves and are not happy when running together (stronger pump blocks flow of weaker), ie harmful to switch secondary on during critical flight. Reflexes being what they are during these times I am considering a fuel pressure (or other switch) that could turn on the second pump if first fails. Any suggestions. I tried to search for this exact issue and had problems. Thanks. > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p=157617#157617 > > > > ________________________________ Message 18 ____________________________________ Time: 05:51:31 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: Europa XS with ULPower 260i engine (OOPS!!!) I just realized that I didn't answer "the question" about justification for OV protection. ALL engine driven power sources fitted with regulators have the ability to produce output voltages well in excess of the system design voltages. RISKS from failure of the regulator are mitigated by (1) the alternator's limited ability to deliver energy (current limit), (2) te alternators open-circuit, runaway limits for voltage and (3) the battery's ability to soak-up what the alternator dishes out for an interval of time sufficient for OV protection to take notice and shut the system down. In the case of an SD-8 driving a 18 a.h. battery, a simple OV warning light might suffice presuming that the owner operator is willing to place him/herself in the OV protection loop. Most designers op for some form of automatic device as do all folks who design systems for certified aircraft. Indeed, all of my z-figures for power generation feature some form of automatic OV protection combined with immediate notification of LOW VOLTAGE that follows. I was concentrating on the operating characteristics of your particular alternator/regulator combination and overlooked the fact that your original question asked about the value of adding OV protection. There are NO votlage regualtors for which probability of runaway failure is ZERO. Some are very good, some are not. Without doing the MTBF/FMEA analysis on every design to be considered, the prudent thing to do is simply include OV protection on every system. This is a 3-phase machine which I presume is more robust than the 18A alternator on a Rotax. It's probably capable of boosting bus votlage to over 16 volts immediately followed by a steady rise to over 18 volts in a matter of minutes. It would not be my personal choice to hope that I would notice and react to a regulator failure for the purpose of mitigating damage to the rest of the system . . . I would recommend inclusion of OV protection. To do this on the AC side of a 3-phase system would require a two-pole relay so perhaps the best approach is leaving the relay on the DC side so it can be a single-pole device. See figure Z-20. Bob . . . At 07:49 PM 1/12/2008 -0500, you wrote: > > >Thanks Bob, > >I am going down to LSA show in Sebring, Florida to see the guys who make >the engine. I hope it works out well for me. > >Vaughn Teegarden > >----- Original Message ----- From: "Robert L. Nuckolls, III" > >To: >Sent: Saturday, January 12, 2008 2:33 PM >Subject: Re: AeroElectric-List: Fw: Europa XS with ULPower 260i engine > > >> >> >>At 05:14 PM 1/8/2008 -0500, you wrote: >> >>> >>>I have received the following reply from the ULPower representatvie to >>>my question, "Why do I not need to include crowbar OV protection with >>>this engine?" >>> >>> >>>Our electronics guy sent me a diagram showing the principle of how our >>>type of regulator works. He says (in Dutch below) that: >>> >>>---------- >>>our type is a "shunt" regulator which shorts the PMG to ground when the >>>battery voltage increases above the nominal level so that the battery >>>can never be over charged and damaged. >>>The principle of a PMG is different to a Regulated Field Generator >>>(typical in cars) where the magnetic field is regulated to vary the >>>voltage of the generator. >>>A PMG acts as a constant current source and therefore may be shorted out. >>> >>>---------- >>>The regulator / rectifier we use is typically used on large capacity >>>motorbikes and our supplier says they are very robust. >>> >>>He also sent the attached schematic: >>> >>>So as I see it, the attached schematic for my airplane should be sufficient. >>> >>>Vaughn Teegarden >> >> What you've proposed will be fine. The regulator >> topology you cited is a carry through of the >> earliest PM alternator regulators. It throttles >> or controls alternator output to the system by >> putting a dead short on the alternator's stator >> windings during short periods where unrestrained >> output would boost the system voltage too much. >> >> This is a very simple approach that has been >> effective since day-one . . . but does have the >> down-side of causing the alternator to run at >> max output current 100% of the time whether that >> energy is used by the electrical system or not. >> Of course, if wire size and cooling considerations >> for the alternator are carefully addressed, this >> can produce a robust, reliable system. >> >> Bob . . . >> >> >> ----------------------------------------) >> ( . . . a long habit of not thinking ) >> ( a thing wrong, gives it a superficial ) >> ( appearance of being right . . . ) >> ( ) >> ( -Thomas Paine 1776- ) >> ---------------------------------------- >> >> >> >> >> > > >-- >269.19.1/1220 - Release Date: 1/11/2008 6:09 PM > > >incoming mail is certified Virus Free. >Checked by AVG. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ------------------------------------------------------------------------------------- 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.