AeroElectric-List Digest Archive

Thu 12/28/06


Total Messages Posted: 10



Today's Message Index:
----------------------
 
     1. 03:05 AM - Re: Re: Back-Up Battery ground (Carlos Trigo)
     2. 06:57 AM - Ocilloscopes (kesleyelectric)
     3. 07:13 AM - Re: AeroElectric-List Digest: 28 Msgs - 12/26/06 (Lee Logan)
     4. 07:30 AM - Re: Re: Back-Up Battery ground (Mike)
     5. 09:40 AM - What Are The Odds (Was Over Voltage) (Sally Kilishek)
     6. 11:43 AM - Re: Ocilloscopes (Ken)
     7. 11:43 AM - Re: What Are The Odds (Was Over Voltage) (Chuck Jensen)
     8. 12:35 PM - Re: What Are The Odds (Was Over Voltage) (sarg314)
     9. 12:43 PM - Re: Ocilloscopes (sarg314)
    10. 04:50 PM - Re: Quest for the One-Word Answers (Robert L. Nuckolls, III)
 
 
 


Message 1


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    Time: 03:05:03 AM PST US
    From: "Carlos Trigo" <trigo@mail.telepac.pt>
    Subject: Re: Back-Up Battery ground
    Yeah Some times on this list, if you ask apples you get an answer in oranges :-) I also hate that particular facet of this group, and I'm waiting for the time when someone asks if he can connect a red ground wire to some device, and he will get the answer that he should not use red on that wire! :-). Well, but most of the times, this forum is useful, so I keep trying. Stan That's exactly what I was asking. Carlos ----- Original Message ----- From: Speedy11@aol.com To: aeroelectric-list@matronics.com Sent: Thursday, December 28, 2006 2:40 AM Subject: AeroElectric-List: Re: Back-Up Battery ground Carlos, Good luck getting a helpful answer on this list. You can normally get little more than criticism and ridicule. It sounds as though you have a ground wire running from your main battery to the aft portion of the fuselage and you want to know if connecting your back-up battery in the aft fuselage to that same ground wire will cause any problems. Is that correct? Stan Sutterfield Do not archive Please forget the reason why I may want to put the Avionics Back-Up battery in the tail, and please answer the electric questions: - Can I connect the (-) terminal of that battery to the tail's ground lug, which is isolated from the fuselage and is directly connected to the (-) terminal of the "Main" battery ? - Can I continue to use that same ground lug to connect the other grounds ( from the tail light, the strobe beacon, and the elevator trim motor) there? - Isn't there any possibility of "ground loop"? Carlos


    Message 2


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    Time: 06:57:06 AM PST US
    From: "kesleyelectric" <kesleyelectric@chooseblue.coop>
    Subject: Ocilloscopes
    Bob and all, I recall a short while ago Bob posted a reference to a very reasonable priced 'scope on the list. It has been 30+ years since I last used one, and I am wondering if it would be a worthwhile investment for crafting/troubleshooting an OBAM aircraft electrical system (rag and tube bushplane, no glass). I have the opportunity to purchase a used ocilloscope locally, and am wondering what applications I might be overlooking. Regards, Tom Barter Kesley, IA Avid Magnum


    Message 3


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    Time: 07:13:22 AM PST US
    From: "Lee Logan" <leeloganster@gmail.com>
    Subject: Re: AeroElectric-List Digest: 28 Msgs - 12/26/06
    Looks like I got that one wrong, if the "official" version of the B1 incident is accurate. I heard it differently, but the general sequence of events in incidents like that seems to have held up. In my experience, crews are sometimes complacent but most often (nearly always) there is some underlying distraction that causes a pilot or crew to forget to put the gear down. You get the fire out, the engine shut down, and the smoke out of the cockpit, but in your haste to save the airplane and yourself/crew by getting on the ground as fast as practicable, you forget the gear. I'm betting there is more to the story than the "executive summary" that we saw. I'd really like to know why the pilot turned over control to the co-pilot right at the last moment. Was it a "test" or something, something wrong with the pilot? Interesting situation. "External evidence" can be very misleading in aircraft accidents. I once managed to survive a near ground impact during a hard turn at a *very* low altitude when my "g" suit blew up (uncommanded, runaway air pressure). Anyone who's had that happen knows the pressure and extreme pain it causes. Had we hit the ground, no one would have ever known what I was struggling with at the time. The investigators would have necessarily concluded I was just hot dogging and killed myself and my back seater. I'm willing to bet 50 cents there is more to this story, even if it's nothing more than something interpersonal, disrespect, or a cockpit argument. Lee...


    Message 4


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    Time: 07:30:04 AM PST US
    From: "Mike" <mlas@cox.net>
    Subject: Re: Back-Up Battery ground
    Ask a better question (more complete), get a better answer. Or you could just bring it over and will fix it. Just helping the sarcasm along! Mike Larkin -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Carlos Trigo Sent: Thursday, December 28, 2006 4:00 AM Subject: Re: AeroElectric-List: Re: Back-Up Battery ground Yeah Some times on this list, if you ask apples you get an answer in oranges :-) I also hate that particular facet of this group, and I'm waiting for the time when someone asks if he can connect a red ground wire to some device, and he will get the answer that he should not use red on that wire! :-). Well, but most of the times, this forum is useful, so I keep trying. Stan That's exactly what I was asking. Carlos ----- Original Message ----- From: HYPERLINK "mailto:Speedy11@aol.com"Speedy11@aol.com "mailto:aeroelectric-list@matronics.com"aeroelectric-list@matronics.com Sent: Thursday, December 28, 2006 2:40 AM Subject: AeroElectric-List: Re: Back-Up Battery ground Carlos, Good luck getting a helpful answer on this list. You can normally get little more than criticism and ridicule. It sounds as though you have a ground wire running from your main battery to the aft portion of the fuselage and you want to know if connecting your back-up battery in the aft fuselage to that same ground wire will cause any problems. Is that correct? Stan Sutterfield Do not archive Please forget the reason why I may want to put the Avionics Back-Up battery in the tail, and please answer the electric questions: - Can I connect the (-) terminal of that battery to the tail's ground lug, which is isolated from the fuselage and is directly connected to the (-) terminal of the "Main" battery ? - Can I continue to use that same ground lug to connect the other grounds ( from the tail light, the strobe beacon, and the elevator trim motor) there? - Isn't there any possibility of "ground loop"? Carlos "http://www.matronics.com/Navigator?AeroElectric-List"http://www.matroni cs.com/Navigator?AeroElectric-List "http://forums.matronics.com"http://forums.matronics.com -- 12/12/2006 -- 12/12/2006


    Message 5


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    Time: 09:40:55 AM PST US
    From: Sally Kilishek <s_kilishek@yahoo.com>
    Subject: What Are The Odds (Was Over Voltage)
    Never to be deterred by experience, I installed yet another new VR749 regulator the other day. This was the fourth one. It worked fine for about 20 minutes, then showed the same behavior as the other three: oscillations between overvoltage of 15+ volts and apparent cut off. What are the odds that four consecutive regulators would be bad? Is there anything else in a plane wired per Z22 that could account for this behavior? Temperatures here are in the 40s and 50s. Could a negative temperature coefficient be causing the regulator set point to rise above 15 volts? George Dennis Haversham wrote: I have the same regulator (VR 749) controlling a 100 amp Mazda alternator. I'm running the engine on the ground while I finish the A/C but I've experienced the same thing. High voltage at the battery... Sally Kilishek wrote: > >I'm using a generic Ford regulator (Wells VR749) and a >B&C OVM-14 overvoltage module wired as per Z-22 in my >RV8. > >It worked fine for a short time, but after about 4 >hours of flying, the overvoltage indicator light >started flickering. Bus voltage is rising above 15 >volts (one time as high as 16 volts), then dropping >back below 15 volts and immediately rising again. > >It looks to me like the regulator isn't regulating and >that the OV module is cutting off the field excitation >until voltage drops below 15. > >I've replaced the regulator twice, but the problem >continues. > >Is there somewhere else I should be looking? > >George >N57GK __________________________________________________


    Message 6


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    Time: 11:43:23 AM PST US
    From: Ken <klehman@albedo.net>
    Subject: Re: Ocilloscopes
    saelig.com has the pds5022 for I think $329. currently. Seems to work as advertised although I can't get the usb driver to install on my windoze98 machine. I agree that it is excellant value for playing with electronic stuff but I doubt that most folks building airplanes would have much use for such a thing. Ken PS. Sorry if I've annoyed anyone by giving an opinion as well as answering the question. Well not really ;) kesleyelectric wrote: > Bob and all, > > I recall a short while ago Bob posted a reference to a very reasonable > priced 'scope on the list. It has been 30+ years since I last used > one, and I am wondering if it would be a worthwhile investment for > crafting/troubleshooting an OBAM aircraft electrical system (rag and > tube bushplane, no glass). I have the opportunity to purchase a used > ocilloscope locally, and am wondering what applications I might be > overlooking. > > Regards, > > Tom Barter > Kesley, IA > Avid Magnum > >


    Message 7


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    Time: 11:43:53 AM PST US
    Subject: What Are The Odds (Was Over Voltage)
    From: "Chuck Jensen" <cjensen@dts9000.com>
    George, Are you measuring the voltage with a minimum of two different instruments? In short, are you sure it is the voltage and not the measuring device/indication? You may have been over this territory before but I didn't see it in the email history below. Perhaps common to all the failures was the same measuring instrument? Chuck Jensen -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Sally Kilishek Sent: Thursday, December 28, 2006 12:39 PM Subject: AeroElectric-List: What Are The Odds (Was Over Voltage) --> <s_kilishek@yahoo.com> Never to be deterred by experience, I installed yet another new VR749 regulator the other day. This was the fourth one. It worked fine for about 20 minutes, then showed the same behavior as the other three: oscillations between overvoltage of 15+ volts and apparent cut off. What are the odds that four consecutive regulators would be bad? Is there anything else in a plane wired per Z22 that could account for this behavior? Temperatures here are in the 40s and 50s. Could a negative temperature coefficient be causing the regulator set point to rise above 15 volts? George Dennis Haversham wrote: I have the same regulator (VR 749) controlling a 100 amp Mazda alternator. I'm running the engine on the ground while I finish the A/C but I've experienced the same thing. High voltage at the battery... Sally Kilishek wrote: > >I'm using a generic Ford regulator (Wells VR749) and a >B&C OVM-14 overvoltage module wired as per Z-22 in my >RV8. > >It worked fine for a short time, but after about 4 >hours of flying, the overvoltage indicator light >started flickering. Bus voltage is rising above 15 >volts (one time as high as 16 volts), then dropping >back below 15 volts and immediately rising again. > >It looks to me like the regulator isn't regulating and >that the OV module is cutting off the field excitation >until voltage drops below 15. > >I've replaced the regulator twice, but the problem >continues. > >Is there somewhere else I should be looking? > >George >N57GK __________________________________________________


    Message 8


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    Time: 12:35:52 PM PST US
    From: sarg314 <sarg314@comcast.net>
    Subject: Re: What Are The Odds (Was Over Voltage)
    Sally: In general the odds are pretty close to 0 unless all four came from the same production lot AND the whole lot was bad. Having spent 20 years in the electronics business I've seen that happen a few times. Of course we bought capacitors, circuit boards, IC's, memory, etc. in rather large quantities. Your regulators may have a lot number printed on them that you could compare to see if they're all the same. That said, it's probably more likely something in your circuit is killing the things rather than getting 4 duds in a row. -- Tom Sargent Sally Kilishek wrote: > >Never to be deterred by experience, I installed yet >another new VR749 regulator the other day. This was >the fourth one. It worked fine for about 20 minutes, >then showed the same behavior as the other three: >oscillations between overvoltage of 15+ volts and >apparent cut off. > >What are the odds that four consecutive regulators >would be bad? > > >


    Message 9


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    Time: 12:43:30 PM PST US
    From: sarg314 <sarg314@comcast.net>
    Subject: Re: Ocilloscopes
    I agree with Ken. I'd like to have an O-scope, but nothing I've encountered yet seems to need more than a multi-meter of some sort. I bought a cheap Fluke meter for $70 or $80, which I recommend. If you want to measure standing wave ratio on one of the radios, you'll need and SWR meter. I actually borrowed one of those from somebody once. Isn't really worth buying one, though. -- Tom Sargent


    Message 10


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    Time: 04:50:46 PM PST US
    From: "Robert L. Nuckolls, III" <nuckollsr@cox.net>
    Subject: Re: Quest for the One-Word Answers
    Yeah, this group really sucks sometimes! There are folks who hang around here just to use it as a personal Q&A Butler . . . the answer is probably in the archives, in the book or even in dozens of places out on the 'net. But to take the (gasp) $time$ to dig it out and understand it . . . . It's obviously easier to ask a question and then presume that what comes back is an acceptable alternative to personal investigation and resolution. The degree of acceptability is often assigned by perceptions "greatness" ascribed to individuals who choose to answer. The questions about the remote battery raised additional questions that an astute designer would add to the mix of issues to be resolved. My duty as teacher dictates that we explore and address as many of those issues as we're capable of . . . do the best we know how to do. It's too bad if this little quirk of mine (and others here on the List) gets in the way of anyone's sensibilities and/or quest for the one-word answer. A simple-idea that has been around for millennia: "You get what you pay for". One may interpret this to mean that since nobody pays much in the way of cash for their participation, disappointments for unrealized expectations should be taken in stride. However, may I suggest that the rudimentary medium of exchange is not dollars but minutes. A minute spent here on the List for any purpose is lost forever and cannot be recovered or re-invested anywhere else. Minutes expended to pose questions for which one desires one-word answers are high risk investments. For example, "will grounding my battery in the tail cause a ground loop?" There is no quick and short answer to that without further exploration . . . Several times a year, somebody will send me a note extolling the virtues of my book. They'll cite great understanding acquired by their participation on the List. Then they toss in some drawings that they claim are "slight adaptations" of figure Z-whatever and they wish to have me look it over. Most even offer to pay my exorbitant consulting fees for the service. What I receive is often difficult to decipher. It seems to be some new architecture with mystery features that are un-explained. The language (schematic symbology) and organization are poor it would take a lot of $time$ just to deduce the ideas much less evaluate them for usefulness. I get a sinking feeling when opening these packages. Somebody has expended a lot of $time$ on the effort with an exceedingly poor prospect for return on investment for either understanding or improved system functionality. Adding to that expense is not productive for me or the customer. I generally toss those packages in the round file and try to forget them. So, Carlos . . . how would you have me (or anyone else here on the List) respond? Your questions for which you desired one-word answers painted a rather startling image in the gray matter of this ol' wire stringer. I can do one of two things: (1) toss your ideas out to the List for consideration not only for the technical but practical merits or (2) toss them in the round file as "un-answerable in the present form - please re-phrase and resubmit." If I offered the one-word answers you sought and the system had problems later, then you might be inclined to whack on that gray-haired ol' f@#t in Wichita who told you it would be okay. So if you're interested in deducing whether or not your proposed architecture is consistent with the best we know how to do, then more details are needed. Carlos and Stan, I'm not trying to sell you a bill of goods. If you find the $time$ spent here on the List to be of poor investment, may I suggest you spend it elsewhere? The same $time$ used to install some rivets or bend some metal might be a much better deal in your situation. But know too that $time$ spent in Mutual Gunching Society meetings does not speak well of anyone's skill in allocation of resources. I hope neither of you believes that your p@#$'n-and-m@#$#ing about the "poor service" here on the List is going to effect any changes. As I write these words, my two-year old niece is throwing a rather noisy fit upstairs for some odd reason or another. It matters not. Her $time$ and effort in this endeavor will have an exceedingly poor return on investment. The choice is yours gentlemen. How may we serve you? Bob . . . >-----Original Message----- >From: owner-aeroelectric-list-server@matronics.com >[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Carlos Trigo >Sent: Thursday, December 28, 2006 4:00 AM >To: aeroelectric-list@matronics.com >Subject: Re: AeroElectric-List: Re: Back-Up Battery ground > >Yeah, > >Some times on this list, if you ask apples you get an answer in oranges :-) > >I also hate that particular facet of this group, and I'm waiting for the >time when someone asks if he can connect a red ground wire to some device, >and he will get the answer that he should not use red on that wire! :-). > >Well, but most of the times, this forum is useful, so I keep trying. > >Stan > >That's exactly what I was asking. > >Carlos >----- Original Message ----- >From: <mailto:Speedy11@aol.com>Speedy11@aol.com >To: <mailto:aeroelectric-list@matronics.com>aeroelectric-list@matronics.com >Sent: Thursday, December 28, 2006 2:40 AM >Subject: AeroElectric-List: Re: Back-Up Battery ground > >Carlos, >Good luck getting a helpful answer on this list. You can normally get >little more than criticism and ridicule. >It sounds as though you have a ground wire running from your main battery >to the aft portion of the fuselage and you want to know if connecting your >back-up battery in the aft fuselage to that same ground wire will cause >any problems. Is that correct? >Stan Sutterfield >Do not archive > >Please forget the reason why I may want to put the Avionics Back-Up battery >in the tail, and please answer the electric questions: > - Can I connect the (-) terminal of that battery to the tail's ground lug, >which is isolated from the fuselage and is directly connected to the (-) >terminal of the "Main" battery ? > - Can I continue to use that same ground lug to connect the other grounds >( from the tail light, the strobe beacon, and the elevator trim motor) >there? > - Isn't there any possibility of "ground loop"? >Carlos




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