AeroElectric-List Digest Archive

Wed 01/06/10


Total Messages Posted: 27



Today's Message Index:
----------------------
 
     1. 01:08 AM - Re: Re: Battery Bus Location (Jay Hyde)
     2. 03:03 AM - Re: Re: [AeroElectric-List] Questions about circuit protection (Jay Hyde)
     3. 04:25 AM - Re: Re: Question about 16V POLYFUSER Radial Leaded Resettable PTC (Neal George)
     4. 06:09 AM - Re: Re: [AeroElectric-List] Questions about circuit protection (ROGER & JEAN CURTIS)
     5. 07:09 AM - Re: Re: [AeroElectric-List] Questions about circuit protection (Carlos Trigo)
     6. 07:25 AM - Re: Question about 16V POLYFUSER Radial Leaded Resettable PTC (al38kit)
     7. 08:02 AM - Re: Battery Bus Location (PaulR)
     8. 08:03 AM - Re: Re: Question about 16V POLYFUSER Radial Leaded Resettable PTC (Dennis Golden)
     9. 08:03 AM - Re: Re: [AeroElectric-List] Questions about circuit protection (Dan Brown)
    10. 08:24 AM - Re: Z-14 Switch Combos (Perry, Phil)
    11. 08:33 AM - Re: Z-14 Switch Combos (Robert L. Nuckolls, III)
    12. 08:56 AM - Re: Re: [AeroElectric-List] Questions about circuit protection (Robert L. Nuckolls, III)
    13. 09:15 AM - Re: Re: Battery Bus Location (Robert L. Nuckolls, III)
    14. 09:31 AM - Re: Re: Battery Bus Location (Robert L. Nuckolls, III)
    15. 09:35 AM - Re: Tachometer problems (Robert L. Nuckolls, III)
    16. 09:41 AM - Re: Re: Question about 16V POLYFUSER Radial Leaded Resettable PTC (Robert L. Nuckolls, III)
    17. 09:47 AM - Re: AeroElectric-List Digest: 16 Msgs - 01/05/10 (Jesse Jenks)
    18. 09:54 AM - Re: [AeroElectric-List] Questions about circuit protection (Carlos Trigo)
    19. 09:54 AM - Re: Re: Question about 16V POLYFUSER Radial Leaded Resettable PTC (George, Neal E Capt USAF ACC 505 TRS/DOJ)
    20. 10:14 AM - Re: Re: [AeroElectric-List] Questions about circuit protection (Bill Mauledriver Watson)
    21. 10:17 AM - Electrical System Planning (Robert L. Nuckolls, III)
    22. 10:48 AM - Re: [AeroElectric-List] Questions about circuit protection (Carlos Trigo)
    23. 10:57 AM - Re: Re: [AeroElectric-List] Questions about circuit protection (ROGER & JEAN CURTIS)
    24. 11:17 AM - Re: Re: [AeroElectric-List] Questions about circuit protection (ROGER & JEAN CURTIS)
    25. 11:54 AM - Re: Re: Question about 16V POLYFUSER Radial Leaded Resettable PTC (jerb)
    26. 02:06 PM - List decorum  (Robert L. Nuckolls, III)
    27. 08:07 PM - Re: Z-14 Switch Combos (Perry, Phil)
 
 
 


Message 1


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    Time: 01:08:21 AM PST US
    From: "Jay Hyde" <jay@horriblehyde.com>
    Subject: Re: Battery Bus Location
    I put one of my battery busses on the hot side of the firewall and the other on the cold side (2 batteries). My reasoning was that I would rather have the connection between the buss and the battery short on the hot side than lead the wire to the cold side. For the second battery, which is located in the cargo compartment, I had to lead a long fat wire to the front, as per my previous mail. The battery bus is located where the fat wire ends at the firewall, on the contactor for that battery. As Bob pointed out, this is not ideal as it means that you have a long fat wire (now protected by an inline fuse as described in my last mail) between the battery and the contactor. The rational for this is that the routing between the front and back is not easy and I would rather have 1 mechanically robust wire than several smaller wires that might be subject to chaffing and damage- the fat wire is much easier to protect mechanically. Not ideal, but adapted to the situation that I have... Jay -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: 06 January 2010 01:30 AM Subject: Re: AeroElectric-List: Re: Battery Bus Location <nuckolls.bob@aeroelectric.com> At 04:10 PM 1/5/2010, you wrote: > >Bob, >Thanks for the reply. I'm not opposed to putting it outside on the >firewall, I just didn't know whether the fuse blocks from B&C would >be alright out there. I think you spell out 6" length on the feed wire. That's an idealized notion. If you need to make it 12" or even longer to satisfy design goals, the world is not going to come to an end. > If I stick to that, which makes sense unprotected, then I would > have to put it directly on the inside of the firewall which would > be extremely difficult to get to for service. Hopefully none will > be required, but it would be easier on the hot side. Then put it in a location for ease of maintenance. That would be my choice as well. Think about a way to at least cover if not box-up the fuseblock like they do under the hood of cars. >The insulator would indeed be a good method to get the wire inside, >but the length is still a factor. The length isn't a REALLY BIG thing, just a good practice design rule adopted by the TC side of the house many years ago. How long would the wire be for both extending the battery feeder AND ease of maintenance? >Does most everyone else put them on the hot side? Good question. How about it guys? Anyone out there flying fuse blocks on the forward side of the firewall? Bob . . .


    Message 2


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    Time: 03:03:13 AM PST US
    From: "Jay Hyde" <jay@horriblehyde.com>
    Subject: RE: [AeroElectric-List] Questions about circuit
    protection I use fuses for my designs as well and add what I call a FAP (Fuse Annunciator Panel) which is an array of LED's that are connected to the 'downsteam' side of the fuse. By pressing a common pushbutton that connects all of the LED's to ground I can immediately see whether all of the fuses are OK. For the pilot this is great- press the button on the pre-flight and the status of all the fuses is shown; and in flight they can check the fuses the same way if there is some suspicion that a fuse has blown. It requires some extra PT with the wiring but I am working on a fuse holder that will make this much easier. My first version was a bit clumsy, but they're getting better. I even have a light test button. :-) Jay _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Jared Yates Sent: 06 January 2010 08:16 AM Subject: RE: AeroElectric-List: RE: [AeroElectric-List] Questions about circuit protection In some of the larger factory-made airplanes, the breakers are situated behind the pilot's head. In this location popped breakers are only obvious if you get up out of your seat to look. It's pretty embarrassing to call the maintenance guys, go through some diagnostics on a non-functioning gadget, then have them instruct you to pull the breaker and doh! It was popped all along. One time I tried to extend the flaps for landing, but they didn't extend because all 5 of the flap motor circuit breakers have been pulled since before takeoff. In that case the mechanics were working on the flaps, pulled the breakers as a normal safety measure, but then forgot to put them in when they were done. Then two pilots didn't notice that they were out, at least not until configuring for the landing. In that airplane the normal flap setting for takeoff was zero. I can think of several other similar stories that illustrate that popped breakers aren't necessarily all that obvious. Once you realize that something isn't working and start looking for a breaker, they might be more obvious than a fuse, unless you spend the extra cents on the bling-bling LED fuses. _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Bob McCallum Sent: Tuesday, January 05, 2010 11:11 PM Subject: RE: AeroElectric-List: RE: [AeroElectric-List] Questions about circuit protection Carlos; Different "Bob" here, but I must disagree with your viewpoint. Please see embedded comments. _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Carlos Trigo Sent: Tuesday, January 05, 2010 8:00 PM Subject: AeroElectric-List: RE: [AeroElectric-List] Questions about circuit protection Bob I really don't want to resuscitate this discussion but, even being aware of the technical advantages of fuses versus circuit breakers, it is indeed almost impossible to convince a pilot that a fuse is better than a circuit breaker. Why?? Fuse is simpler, less expensive, probably neater, and serves its intended purpose admirably. I've been a pilot for 35 years, a builder for only 5 and I much prefer the simplicity and economy of fuses. I consider myself a pilot first and I don't need convincing, I know fuses are better. (At least in my own mind they are) In flight, when a fuse blows, the pilot will hardly notice it, and even if some device (whose circuit was protected by that fuse) becomes blank, he will not know if it was the fuse or anything else that caused that device to die. And how is that any different than the symptoms presented by a tripped breaker? The supplied device ceases to function in either case. To the pilot operating the aircraft there is no difference, he looses the benefit of whatever widget was supplied power by that circuit. If a circuit breaker pops out, there is a big probability the pilot will immediately notice it, How or why will he notice it?? and why does it matter?? or at least after seeing any device die, he will immediately look to the circuit breakers heads to look for the one that popped out. Are you making the assumption that the breakers are somehow readily available, visible and accessible in flight?? What if the breakers are neatly hidden away up under the panel, are on a fold down bracket, or in some other manner not readily apparent to the pilots position or his line of sight? What if the breaker that faults is one on the battery buss, hidden away in the tail cone next the battery? How does that present some different scenario to the pilot than would a fuse?? Being a pilot trained for so many things, he must also know that he shall not push that particular breaker in, unless he wants to light up the fire which will burn his own ass. All the more reason for, and another demonstration of, the superiority of hidden fuses. (Or hidden breakers for that matter) Removes the temptation and doesn't require the discipline and willpower "not to reset". It is probably easy to convince an aircraft builder to prefer fuses, but since in the OBAM world we are builders AND pilots, circuit breakers are certainly much more user friendly for the pilot, even knowing that the PILOT is the most dangerous single-point-of-failure in a flying aircraft I really fail to see the "user friendly" analogy. The fuses in all the cars I've owned have been about as "user friendly" as I can imagine, and in some of my cars I never had occasion to even learn where they were. Can't remember the last time one ever blew. In the dozen or so types of aircraft I'm checked out in, I can't remember the last time a fuse blew, or a breaker tripped either. In a properly designed and functioning car or aircraft, I wouldn't "expect" the circuit protection devices to be called upon to do their job for the life of the vehicle, be it airborne or ground based. I fully agree with the "insurance" provided by their presence, but wouldn't expect them to be called upon. (If breakers are somehow superior, why do the millions of cars on the road use fuses?) As Bob explained the main reason aircraft migrated to expensive breakers was to mitigate the drawbacks of "old" technology glass cartridge fuses such as loose retaining caps and low pressure contacts prone to corrosion. We now have modern "blade" fuses without these shortcomings. Don't get me wrong, I fully understand and respect your opinion and viewpoint, I just can't get a grasp on the logic behind it. As one who makes a living as an engineer, I view simple as better and fuses are simpler and less expensive than breakers and have much less chance of having something go wrong with them which makes the pilot side of me much more relaxed and comfortable with fuses than breakers. Carlos Respectfully, Bob McC http://www.matronics.com/Navigator?AeroElectric-List http://forums.matronics.com http://www.matronics.com/contribution


    Message 3


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    Time: 04:25:54 AM PST US
    From: "Neal George" <n8zg@mchsi.com>
    Subject: Re: Question about 16V POLYFUSER Radial Leaded
    Resettable PTC No sir. We put switches on electrical circuits to provide On/Off control of the load under normal operations. Once an overload condition manifests, operations are no longer normal. Powering a circuit that you know has experienced an overload invites smoke, flame and fury in a confined space with no reasonable exit. War story follows: Standing nuclear alert in the missile fields around Cheyenne, WY, our procedures allowed ONE attempt to reset a tripped circuit breaker, after a specified cool-down period. Smoke in the capsule is bad, and getting out is neither easy nor quick. Neal I can understand the concern for a circuit resetting itself after the power is restored...but isn't that a reason we put switches on things?...Like leave that circuit off if it has a problem... Sorry, just don't see the design as having much of a downside. If you think you may accidentally turn the thing back on, put some red tape on the switch or something...pull the wire. Al


    Message 4


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    Time: 06:09:06 AM PST US
    From: "ROGER & JEAN CURTIS" <mrspudandcompany@verizon.net>
    Subject: RE: [AeroElectric-List] Questions about circuit
    protection Bob I really don't want to resuscitate this discussion but, even being aware of the technical advantages of fuses versus circuit breakers, it is indeed almost impossible to convince a pilot that a fuse is better than a circuit breaker. In flight, when a fuse blows, the pilot will hardly notice it, and even if some device (whose circuit was protected by that fuse) becomes blank, he will not know if it was the fuse or anything else that caused that device to die. If a circuit breaker pops out, there is a big probability the pilot will immediately notice it, or at least after seeing any device die, he will immediately look to the circuit breakers heads to look for the one that popped out. Being a pilot trained for so many things, he must also know that he shall not push that particular breaker in, unless he wants to light up the fire which will burn his own ass. It is probably easy to convince an aircraft builder to prefer fuses, but since in the OBAM world we are builders AND pilots, circuit breakers are certainly much more user friendly for the pilot, even knowing that the PILOT is the most dangerous single-point-of-failure in a flying aircraft Carlos .Two simple examples: 1) You are flying along in your airplane with circuit breakers, the radio goes dead, and a breaker button pops out. What do you do? Fly the airplane!! 2) You are flying along in your airplane with Fuses, the radio goes dead, and nothing else happens. What do you do? Fly the airplane!! When you get on the ground you troubleshoot the problem. If the added cost for the row of little buttons to pop out, on the dash, gives you a sense of security, I say GO FOR IT...... rOGER


    Message 5


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    Time: 07:09:26 AM PST US
    From: "Carlos Trigo" <trigo@mail.telepac.pt>
    Subject: RE: [AeroElectric-List] Questions about circuit
    protection .Two simple examples: 1) You are flying along in your airplane with circuit breakers, the radio goes dead, and a breaker button pops out. What do you do? Fly the airplane, knowing that something happened in the electric circuit that is protected by that particular circuit breaker. If the radio (or anything else that went dead) is not critical to your flight, you complete it with no other worries 2) You are flying along in your airplane with Fuses, the radio goes dead, and nothing else happens. What do you do? Fly the airplane!! not knowing what happened. Did I loose the alternator? Is there anything that is going to start a fire? What should I do? Should I land ASAP? Shall I declare an emergency? Next, anything can happen to the pilot, even panic When you get on the ground you troubleshoot the problem. If it was a fuse, it can take some time to find out which. If it was a circuit breaker, I will go IMMEDIATELY to the source of the problem If the added cost for the row of little buttons to pop out, on the dash, gives you a sense of security, I say GO FOR IT...... I have 1 airplane with fuses, 1 airplane with cb's, and the one I'm finishing building have both. Not biased, though. :-) Only analysing pros and cons. Carlos


    Message 6


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    Time: 07:25:19 AM PST US
    Subject: Re: Question about 16V POLYFUSER Radial Leaded Resettable
    PTC
    From: "al38kit" <alfranken@msn.com>
    Neal...having spent some time in the military myself, I know there is ofter not much thinking that is to be done, and a procedure for almost everything... That being said and that we are no longer held to that kind of procedure, what's the down side to leaving the switch off? No one says you have to reset it. My understanding is that once the electrons are removed from the circuit, it's dead. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=280355#280355


    Message 7


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    Time: 08:02:30 AM PST US
    Subject: Re: Battery Bus Location
    From: "PaulR" <prose@panhandle.rr.com>
    [/quote] The length isn't a REALLY BIG thing, just a good practice design rule adopted by the TC side of the house many years ago. How long would the wire be for both extending the battery feeder AND ease of maintenance? I think i could get by with 18-24" depending on how "easily maintainable" it is. While it's really too cold to heat the shop up for a couple hours, I think I'll see if I can find a covered fuse block until I'm back in the shop over the weekend -------- Paul Rose N417PR (res) RV-9A Read this topic online here: http://forums.matronics.com/viewtopic.php?p=280358#280358


    Message 8


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    Time: 08:03:19 AM PST US
    From: Dennis Golden <dgolden@golden-consulting.com>
    Subject: Re: Question about 16V POLYFUSER Radial Leaded
    Resettable PTC al38kit wrote: > > Neal...having spent some time in the military myself, I know there is ofter not much thinking that is to be done, and a procedure for almost everything... > > That being said and that we are no longer held to that kind of procedure, what's the down side to leaving the switch off? > > No one says you have to reset it. > > My understanding is that once the electrons are removed from the circuit, it's dead. What if the fault IS the switch, or the wiring going TO the switch. Dennis -- Dennis Golden Golden Consulting Services, Inc.


    Message 9


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    Time: 08:03:19 AM PST US
    From: Dan Brown <dan@familybrown.org>
    Subject: RE: [AeroElectric-List] Questions about circuit
    protection Quoting Carlos Trigo <trigo@mail.telepac.pt>: > 2) You are flying along in your airplane with Fuses, the radio goes dead, > and nothing else happens. What do you do? Fly the airplane!! not knowing > what happened. Did I loose the alternator? Is there anything that is going > to start a fire? What should I do? Should I land ASAP? Shall I declare an > emergency? Next, anything can happen to the pilot, even panic Losing the alternator won't take out the radio, unless you don't have a battery (in which case it will take out everything electrical). Losing the alternator will, however, activate the low-voltage warning that you have installed (don't you?), letting you know that you're running on battery power. If you're panicking (as most of your questions sound like) over losing one radio, you probably shouldn't be a pilot. > When you get on the ground you troubleshoot the problem. If it was a fuse, > it can take some time to find out which. If it takes you more than 30 seconds to find which fuse goes to that radio, you haven't designed or labeled your electrical system very well. -- Dan Brown, KE6MKS, dan@familybrown.org "Since all the world is but a story, it were well for thee to buy the more enduring story rather than the story that is less enduring." -- The Judgment of St. Colum Cille


    Message 10


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    Time: 08:24:45 AM PST US
    Subject: Z-14 Switch Combos
    From: "Perry, Phil" <Phil.Perry@netapp.com>
    Hey Bob, It looks like the crossfeed switch doubles as a starter switch in your diagram, is that correct? I'm planning on going with a push button to start, so I'll probably modify the setup slightly. But just want to make sure I'm reading it correctly. Thanks, Phil -----Original Message----- From: Robert L. Nuckolls, III [mailto:nuckolls.bob@aeroelectric.com] Sent: Tuesday, January 05, 2010 9:29 AM Subject: RE: AeroElectric-List: Z-14 Switch Combos <nuckolls.bob@aeroelectric.com> At 09:08 PM 1/4/2010, you wrote: > >Phil - > >I think you misinterpreted Bob's comment. It appears you read it to say >"you're never ALLOWED to close the cross-feed switch", when Bob meant "you >might not ever have a reason to close it". > >Neal Correct. The process for deciding how to operate Z-14 is dependent upon what devices are fed from each bus and how you use the airplane. Z-14 was originally crafted for a guy building a Glasair with full up IFR capability in both seats. Further, it was the builder's intent to use this machine in missions that most of us work hard to avoid. Z-14 offers OPTIONS for deciding how you will manage energy resources that have become limited due to failure of some component like an alternator or battery contactor. There is no SET PROCEDURE I can offer you without doing the same failure modes effects analysis I would conduct for a TC aircraft with a similar system installed and tailored to the most demanding mission for which the airplane is outfitted. Z-14's cross-feed contactor solved a problem with attempting to PARALLEL two alternators in a dual alternator airplane by making them responsible for SEPARATE systems in normal operations. Z-13/8 was crafted to take exploit the existence of an unused engine accessory drive pad when a vacuum pump is removed. Some politicians hate to waste a good crisis, I had to waste a good drive pad. When considered against the quantum jumps in reliability offered by modern alternators and artfully maintained RG batteries, I believe Z-13/8 is about the most elegant solution to powering up the light airplane for 99 plus percent of all OBAM aircraft. If you have Z-14 installed, then share with us how equipment in your airplane is powered from the two busses along with your vision of how you expect to use this airplane. Is it important to you to forestall a dark-n-stormy night story 'cause you've had an alternator go belly up while night IFR over the Rockies crossing a weather front? If so, what items of equipment are installed and how are they spread between the two systems? Bob . . .


    Message 11


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    Time: 08:33:42 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Z-14 Switch Combos
    At 10:19 AM 1/6/2010, you wrote: > >Hey Bob, > >It looks like the crossfeed switch doubles as a starter switch in your >diagram, is that correct? Yes . . . it's spring loaded out of the start position. It offers automatic closure of the cross-feed contactor during start. >I'm planning on going with a push button to start, so I'll probably >modify the setup slightly. But just want to make sure I'm reading it >correctly. Then the cross-feed switch can be SPST. Bob . . .


    Message 12


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    Time: 08:56:26 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: RE: [AeroElectric-List] Questions about circuit
    protection At 07:00 PM 1/5/2010, you wrote: >Bob > >I really don=92t want to resuscitate this >discussion but, even being aware of the >technical advantages of fuses versus circuit >breakers, it is indeed almost impossible to >convince a pilot that a fuse is better than a circuit breaker. It has never been offered as 'better' . . . only adequate to the task of meeting design goals in a failure tolerant system. >In flight, when a fuse blows, the pilot will >hardly notice it, and even if some device (whose >circuit was protected by that fuse) becomes >blank, he will not know if it was the fuse or >anything else that caused that device to die. Have you read . . . http://www.aeroelectric.com/articles/fusvbkr2.html >If a circuit breaker pops out, there is a big >probability the pilot will immediately notice >it, or at least after seeing any device die, he >will immediately look to the circuit breakers >heads to look for the one that popped out. >Being a pilot trained for so many things, he >must also know that he shall not push that >particular breaker in, unless he wants to light >up the fire which will burn his own ass=85 It's not clear that you embrace/understand the rationale presented for unreachable fuse-blocks. Certainly everyone has a choice to make and in the final analysis it's personal. I did a power distribution diagram for the BD-10 jet about 15 years ago. I bounced the idea of fuse-blocks off the electrical systems wienie. He agreed that they were adequate to the task but opined that anyone building a BD-10 wanted that "busy fighter cockpit look. The more knobs, buttons and switches the better." But even after the drawing was completed using breakers throughout, he about had a cow when I put about a dozen breakers back in the engine compartment. The architecture called for protection in these feeders and the sources for those feeders were in the tail. Further, there was no failure mode effects analysis that supported any need for pilot access to these breakers whatsoever. Nonetheless, he insisted on having all breakers in the cockpit. I submitted my bill for work accomplished to date and bowed out of the project. Got a nastygram from Mr. Bede hisself honking about the fee and stating that his electro-wienie wasn't authorized to make contracts. I settled for 50 cents on the dollar and chalked it up to the fates. Have you identified errors in the logic offered in many published pieces on the website and here on the List that speak to suitability of fuses? If not, then like the BD-10 episode, it's a matter of preference. Breakers and their panels are not unsafe. They're only heavier, more expensive, take up panel space, require hours of fabrication time, restrict wire bundle routing options, offer no enhanced level of safety and MAY be distracting to a pilot who should be doing more important things. But if one chooses breakers, they're in good company. The vast majority of the GA fleet is carrying tons of them around the sky with a vanishingly small probability that any single breaker will ever be called upon to do its job. Bob . . .


    Message 13


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    Time: 09:15:03 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Battery Bus Location
    At 10:00 AM 1/6/2010, you wrote: > >[/quote] > The length isn't a REALLY BIG thing, just a > good practice design rule adopted by the TC > side of the house many years ago. How long would > the wire be for both extending the battery > feeder AND ease of maintenance? > > I think i could get by with 18-24" depending on how "easily > maintainable" it is. > >While it's really too cold to heat the shop up for a couple hours, I >think I'll see if I can find a covered fuse block until I'm back in >the shop over the weekend Think about building a cover. The fuse-blocks mount with 4 screws. The "nut" for each of those fasteners could be a thru-hole, threaded spacer of sufficient height to just clear the tops of the fuses. Four thumb-nut screws would be used to mount the cover down to the tops of the spacers. A cover might be nothing more than a sheet with four folded down edges having notches for clearing wire bundles. I've been thinking about having some ABS covers made. A friend of mine does deep vacuum forming as a part of his manufacturing operations. Another option is to make the cover out of copper clad. See: http://www.aeroelectric.com/articles/cladboard/cladboard.html http://aeroelectric.com/Pictures/Data_Acquisition/Weeder_Module_DAS_1.jpg http://aeroelectric.com/Pictures/Data_Acquisition/Weeder_Module_DAS_2.jpg I've built robust enclosures out of this stuff. You only need to cut some accurate rectangular pieces, fixture them against square corners for soldering, run a bead of solder down the inside corner for assembly. Single sided clad gives you a fiberglas/epoxy outside surface that takes paint very nicely. Bob . . .


    Message 14


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    Time: 09:31:07 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Battery Bus Location
    ><snip> I would rather >have 1 mechanically robust wire than several smaller wires that might be >subject to chaffing and damage- the fat wire is much easier to protect >mechanically. Not ideal, but adapted to the situation that I have... The legacy rationale for incorporating an always hot wire into an airframe recognizes the limited ability of circuits protected at 5A or less to start post-crash fires. Extending the battery bus on a long feeder calls for protection of that feeder at some current level larger (and SLOWER) than total draw of accessories fed by the battery bus. Further, one should consider the dynamics of interaction between fuses at the bus and protection at the source end of the feeder. Bus feeders are generally CURRENT LIMITERS with high tolerance to overload. If a fast fuse is used upstream of a bus of fast fuses, one needs to make sure that popping a bus fuse doesn't take the upstream fuse too. Remember that the upstream fuse is "pre-heated" by total loads on the battery bus. Faulting one of the 5A fuses on the bus could trip a 20A feeder protection and take the whole bus down. When the case is finally adjudicated, I'll be able to share how a stack-up of "little details" about fault- trip dynamics brought down a nearly new, very expensive airplane while getting folks hurt in the process. If the battery bus is back in the tail, then any feeders coming forward don't need extra-ordinary protection. They're lightly fused and risks for faulting any single feeder are low. Once the bus feeder turns into a fat wire, the legacy design philosophy for always hot wires is worthy of consideration. Bob . . .


    Message 15


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    Time: 09:35:05 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Tachometer problems
    >Could anyone suggest some specific combination of >capacitor/resistor/diode inline or parallel to the tacho I could try >to smooth things out? Failed to get any help from VDO so any >advice would be very much appreciated. It's a WAG. Without knowing how the input circuits of the tachometer are crafted, then it's VERY difficult to figure out what it doesn't like about the signal provided by your magneto p-leads. The fact that the reading "drops" suggests a low signal level . . . hard to imagine on a p-lead! However, the VDO input signal conditioning may have over-attenuated the incoming signal as a by-product of their own design goals for signal conditioning. In this case, there's not much you can do outside the tach short of building some sort of signal- conditioning device to satisfy the tachometer's demands. Bob . . .


    Message 16


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    Time: 09:41:21 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Question about 16V POLYFUSER Radial Leaded
    Resettable PTC At 10:23 PM 1/5/2010, you wrote: > >I have an EXP bus that I have been considering for my >project. (That I got for a $40, delivered.) It looks like a slick unit > >Sorry, just don't see the design as having much of a downside. If >you think you may accidentally turn the thing back on, put some red >tape on the switch or something...pull the wire. Have you read the discussions on this topic? Goto http://aeroelectric.com and do a a site search on . . . exp bus Keep in mind that a polyswitch MUST be powered to STAY tripped. Fault current is reduced to a "safe" level thus keeping it hot after a trip. Bob . . .


    Message 17


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    Time: 09:47:50 AM PST US
    From: Jesse Jenks <jessejenks@hotmail.com>
    Subject: RE: AeroElectric-List Digest: 16 Msgs - 01/05/10
    Hi guys=2C (I wish there were some girls here too=2C then I wouldn't have t o waste time on Facebook) I've been listening here for a few years while building my Murphy Rebel=2C and now I think I'm actually ready to start wiring. I'm planning to use Z-1 1 and have an occasional-IFR panel with a Garmin 430 and Dynon EFIS. I'm st ill at the very basic planning phase. I already have a Plane Power 60amp IR alternator and a Skytec starter to go on my O-320. That's it=2C the rest i s a blank sheet of paper. I am starting to visualize wire routing and compo nent placement. I have a couple of beginner questions at this point to help with this visualization process: 1)With the P.P. alternator I will obviously not have the seperate voltage r egulator=2C but do I still need the crowbar over voltage protection? 2)The Skytec starter has it's own contactor to engage the gear=2C and apply power to the motor. According to Skytec=2C I don't need a seperate contact or for the starter if I use a 20+amp starter switch=2C which I plan to do ( toggle mag switches and seperate starter switch) Are there any cautions for not using a seperate starter contactor? Thanks. Jesse _________________________________________________________________ Hotmail: Free=2C trusted and rich email service.


    Message 18


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    Time: 09:54:06 AM PST US
    From: "Carlos Trigo" <trigo@mail.telepac.pt>
    Subject: RE: [AeroElectric-List] Questions about circuit protection
    Dear Dan I shouldn't be a pilot (which I am for over 32 years now), I didn't design or labelled very well my electrical system (which I've done many times), then, with all the respect, you shouldn't be commenting. sir! Best regards Carlos P.S. You probably didn't read the part of my last comment (the only in which I didn't panic) when I said I built and fly one airplane with fuses, one airplane with circuit breakers, and the one I'm currently finishing building have both. Don't loose your time, just hit the delete button > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list- > server@matronics.com] On Behalf Of Dan Brown > Sent: quarta-feira, 6 de Janeiro de 2010 16:02 > To: aeroelectric-list@matronics.com > Subject: RE: AeroElectric-List: RE: [AeroElectric-List] Questions about circuit > protection > > > Quoting Carlos Trigo <trigo@mail.telepac.pt>: > > > 2) You are flying along in your airplane with Fuses, the radio goes dead, > > and nothing else happens. What do you do? Fly the airplane!! not knowing > > what happened. Did I loose the alternator? Is there anything that is going > > to start a fire? What should I do? Should I land ASAP? Shall I declare an > > emergency? Next, anything can happen to the pilot, even panic > > Losing the alternator won't take out the radio, unless you don't have > a battery (in which case it will take out everything electrical). > Losing the alternator will, however, activate the low-voltage warning > that you have installed (don't you?), letting you know that you're > running on battery power. If you're panicking (as most of your > questions sound like) over losing one radio, you probably shouldn't be > a pilot. > > > When you get on the ground you troubleshoot the problem. If it was a fuse, > > it can take some time to find out which. > > If it takes you more than 30 seconds to find which fuse goes to that > radio, you haven't designed or labeled your electrical system very well. > > -- > Dan Brown, KE6MKS, dan@familybrown.org > "Since all the world is but a story, it were well for thee to buy the > more enduring story rather than the story that is less enduring." > -- The Judgment of St. Colum Cille > > > > >


    Message 19


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    Time: 09:54:06 AM PST US
    Subject: Re: Question about 16V POLYFUSER Radial Leaded
    Resettable PTC
    From: "George, Neal E Capt USAF ACC 505 TRS/DOJ" <Neal.George@hurlburt.af.mil>
    I set the premise poorly - let me try again. On alert, operating a nuclear delivery system, the goal is to maintain maximum operational capability and flexibility. To that end, the Technical Order REQUIRED _one_ attempt to restore a tripped circuit breaker, forbade more than one attempt, and also forbade holding an offending CB closed. In this situation, the down side to leaving the switch OFF is some reduction in either capability or flexibility, depending (of course) on which system is compromised. On the other hand, NOTHING electrical (except the spark-maker) on my RV is so critical to my continued survival that it will require troubleshooting before I get on the ground comfortably. My panel contains exactly one breaker - the Crowbar OVM. If it trips, I leave it alone, enable the SD8 and decide whether to land soon or later. ============ Neal...having spent some time in the military myself, I know there is ofter not much thinking that is to be done, and a procedure for almost everything... That being said and that we are no longer held to that kind of procedure, what's the down side to leaving the switch off? No one says you have to reset it. My understanding is that once the electrons are removed from the circuit, it's dead.


    Message 20


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    Time: 10:14:31 AM PST US
    From: Bill Mauledriver Watson <MauleDriver@nc.rr.com>
    Subject: Re: RE: [AeroElectric-List] Questions about circuit
    protection This fuse versus CB discussion raises this questions with me - perhaps someone can clear it up. Are any of the current/modern avionic boxes really depending on the CB or fuse for their internal 'protection' of anything? I know many units specify a fuse/CB size and sometimes a wire size but I just size the fuse to protect the wire and try to use a limited number of adequate wire sizes. My understanding is that various units have various means of protecting themselves from spikes, etc. And if any kind of failure starts drawing more amps than the wire/fuse/cb can provide, pop goes the external protection. So I'm thinking that if the radio fails, it fails and I use the backup radio. If the wire leading to the radio shorts on rough edge or something, the radio fails and I use the backup radio. And since fuses are so cheap, I have a separate circuit for practically every unit on the panel so there is a 1:1 ratio between units and fuses. If multiple things fail, then it's an electrical system problem - haven't worked out the details yet but I hope on my Z-14, I just crossfeed to use the backup Alt/Batt system or otherwise go to the backups. And if it smokes, open the windows, make sure it stopped smoking or hit a master until it does. Land ASAP. What are the holes in this thinking? Carlos Trigo wrote > *.Two simple examples:* > * * > *1)** **You are flying along in your airplane with **circuit breakers**, the radio goes dead, and a breaker button pops out. What do you do? **Fly the airplane**, knowing that something happened in the electric circuit that is protected by that particular circuit breaker. If the radio (or anything else that went dead) is not critical to your flight, you complete it with no other worries* > *2)** **You are flying along in your airplane with **Fuses**, the radio goes dead, and nothing else happens. **What do you do? **Fly the airplane!!** not knowing what happened. Did I loose the alternator? Is there anything that is going to start a fire? What should I do? Should I land ASAP? Shall I declare an emergency? Next, anything can happen to the pilot, even panic* > * * > *When you get on the ground you troubleshoot the problem. **If it was a fuse, it can take some time to find out which. If it was a circuit breaker, I will go IMMEDIATELY to the source of the problem* > * * > *If the added cost for the row of little buttons to pop out, on the dash, gives you a sense of security, I say GO FOR IT......** I have 1 airplane with fuses, 1 airplane with cbs, and the one Im finishing building have both. Not biased, though **J** Only analysing pros and cons* > * * > *Carlos* > * * > * * > * > > > *


    Message 21


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    Time: 10:17:27 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Electrical System Planning
    At 11:45 AM 1/6/2010, you wrote: I'm planning to use Z-11 and have an occasional-IFR panel with a Grmin 430 and Dynon EFIS. I'm still at the very basic planning phase. Do you plan to have vacuum driven instruments? If not why not Z13/8? 1)With the P.P. alternator I will obviously not have the separate voltage regulator, but do I still need the crowbar over voltage protection? Plane Power INCLUDES crowbar OV protection on their OBAM aircraft alternators. 2)The Skytec starter has it's own contactor to engage the gear, and apply power to the motor. According to Skytec, I don't need a separate contactor for the starter if I use a 20+amp starter switch, which I plan to do (toggle mag switches and separate starter switch) Are there any cautions for not using a separate starter contactor? No. Bob . . .


    Message 22


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    Time: 10:48:55 AM PST US
    From: "Carlos Trigo" <trigo@mail.telepac.pt>
    Subject: RE: [AeroElectric-List] Questions about circuit protection
    'Lectric Bob I do agree with you. Fuses have many technical advantages, weight, price, simplicity of wiring and others. I also agree with you that it is a matter of choice or preference. That's why, in my perspective as a pilot, I do prefer circuit breakers. >From me, end of discussion. Thanks Carlos _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: quarta-feira, 6 de Janeiro de 2010 16:55 Subject: Re: AeroElectric-List: RE: [AeroElectric-List] Questions about circuit protection At 07:00 PM 1/5/2010, you wrote: Bob I really don't want to resuscitate this discussion but, even being aware of the technical advantages of fuses versus circuit breakers, it is indeed almost impossible to convince a pilot that a fuse is better than a circuit breaker. It has never been offered as 'better' . . . only adequate to the task of meeting design goals in a failure tolerant system. In flight, when a fuse blows, the pilot will hardly notice it, and even if some device (whose circuit was protected by that fuse) becomes blank, he will not know if it was the fuse or anything else that caused that device to die. Have you read . . . http://www.aeroelectric.com/articles/fusvbkr2.html If a circuit breaker pops out, there is a big probability the pilot will immediately notice it, or at least after seeing any device die, he will immediately look to the circuit breakers heads to look for the one that popped out. Being a pilot trained for so many things, he must also know that he shall not push that particular breaker in, unless he wants to light up the fire which will burn his own ass. It's not clear that you embrace/understand the rationale presented for unreachable fuse-blocks. Certainly everyone has a choice to make and in the final analysis it's personal. I did a power distribution diagram for the BD-10 jet about 15 years ago. I bounced the idea of fuse-blocks off the electrical systems wienie. He agreed that they were adequate to the task but opined that anyone building a BD-10 wanted that "busy fighter cockpit look. The more knobs, buttons and switches the better." But even after the drawing was completed using breakers throughout, he about had a cow when I put about a dozen breakers back in the engine compartment. The architecture called for protection in these feeders and the sources for those feeders were in the tail. Further, there was no failure mode effects analysis that supported any need for pilot access to these breakers whatsoever. Nonetheless, he insisted on having all breakers in the cockpit. I submitted my bill for work accomplished to date and bowed out of the project. Got a nastygram from Mr. Bede hisself honking about the fee and stating that his electro-wienie wasn't authorized to make contracts. I settled for 50 cents on the dollar and chalked it up to the fates. Have you identified errors in the logic offered in many published pieces on the website and here on the List that speak to suitability of fuses? If not, then like the BD-10 episode, it's a matter of preference. Breakers and their panels are not unsafe. They're only heavier, more expensive, take up panel space, require hours of fabrication time, restrict wire bundle routing options, offer no enhanced level of safety and MAY be distracting to a pilot who should be doing more important things. But if one chooses breakers, they're in good company. The vast majority of the GA fleet is carrying tons of them around the sky with a vanishingly small probability that any single breaker will ever be called upon to do its job. Bob . . .


    Message 23


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    Time: 10:57:24 AM PST US
    From: "ROGER & JEAN CURTIS" <mrspudandcompany@verizon.net>
    Subject: RE: [AeroElectric-List] Questions about circuit
    protection Dear Dan I shouldn't be a pilot (which I am for over 32 years now), I didn't design or labelled very well my electrical system (which I've done many times), then, with all the respect, you shouldn't be commenting. sir! Best regards Carlos P.S. You probably didn't read the part of my last comment (the only in which I didn't panic) when I said I built and fly one airplane with fuses, one airplane with circuit breakers, and the one I'm currently finishing building have both. Don't loose your time, just hit the delete button Carlos, my friend, You have apparently made up your mind that circuit breakers are superior to fuses, even though several people on the forum have tried to show you the logic and advantages of fuses. May I suggest that you finish building your aircraft, using resettable circuit breakers, since this gives you a greater comfort level. Roger


    Message 24


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    Time: 11:17:12 AM PST US
    From: "ROGER & JEAN CURTIS" <mrspudandcompany@verizon.net>
    Subject: RE: [AeroElectric-List] Questions about circuit
    protection If multiple things fail, then it's an electrical system problem - haven't worked out the details yet but I hope on my Z-14, I just crossfeed to use the backup Alt/Batt system or otherwise go to the backups. And if it smokes, open the windows, make sure it stopped smoking or hit a master until it does. Land ASAP. Bill, I think you have it right! However if I had multiple failures, I believe that I would be heading for "Terra Firma" without delay. Roger


    Message 25


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    Time: 11:54:50 AM PST US
    From: jerb <ulflyer@verizon.net>
    Subject: Re: Question about 16V POLYFUSER Radial Leaded
    Resettable PTC With regards to the use of Polyfues I believe there was something in a recent issue of Kit Planes (hunting for it now) that the FAA does not accept their use in certified aircraft - some thing about if there is a problem with a circuit they want the circuit protection to keep the circuit disabled and not to re-energize itself automatically. You may be able to use them in experimental but if your building in Sport LSA, that may be an issue. I'm trying to find the issue and page where I read this. jerb At 08:23 PM 1/5/2010, you wrote: > >I have an EXP bus that I have been considering for my >project. (That I got for a $40, delivered.) It looks like a slick unit. > >I can understand the concern for a circuit resetting itself after >the power is restored...but isn't that a reason we put switches on >things?...Like leave that circuit off if it has a problem... > >Sorry, just don't see the design as having much of a downside. If >you think you may accidentally turn the thing back on, put some red >tape on the switch or something...pull the wire. > >Al > > >Read this topic online here: > >http://forums.matronics.com/viewtopic.php?p=280326#280326 > >


    Message 26


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    Time: 02:06:14 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: List decorum
    At 12:55 PM 1/6/2010, you wrote: > >P.S. You probably didn't read the part of my last comment (the only >in which I didn't panic) when I said I built and fly one airplane >with fuses, one airplane with circuit breakers, and the one I'm >currently finishing building have both. Don't loose your time, just >hit the delete button > > >May I suggest that you finish building your aircraft, using >resettable circuit breakers, since this gives you a greater comfort level. > > >Roger > Gentlemen, this isn't about "superiority" of anything over anything else. It's about meeting design goals for what we hope will be a failure tolerant system understood by the pilot and sufficiently fitted to meet the missions for which the airplane is built. The pantry of electro-goodies that can be stirred into a host of recipes for success is huge. Just because any one of us has a preference over one ingredient vs. another should not be taken as an invitation to cast disparaging remarks. The mission for each of us on the List is to offer/acquire understanding of how each ingredient functions in particular situations . . . and not to suggest that anyone has made a poor choice EXCEPT where we perceive a risk for not achieving failure tolerance . . . even if the "preferred" system is heavier, costlier, perhaps more complex, or uses breakers. We have a number of folks putting Z-14 into two-place airplanes with missions that will never tax the system's ability to mitigate risk. At the same time, for each individual on the List who has expressed an interest in exploring the possibilities, there are many, Many, MANY more who are wiring their airplanes like a 1969 C-172. Are those folks at extra-ordinary risk for a bad day in the cockpit? No, a modern alternator, active notification of LV, modern RG battery and a purpose-driven battery maintenance program makes them 10x better off than we were in 1950 with generators and lead-acid slop-pots. The OBAM aviation community, indeed all of light aircraft GA is under incremental, relentless attack to simply go away. Our collective future is best served by helping every OBAM aircraft builder generate and meet design goals consistent with the best we know how to do . . . while accommodating their preferences. Bob . . .


    Message 27


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    Time: 08:07:42 PM PST US
    Subject: Z-14 Switch Combos
    From: "Perry, Phil" <Phil.Perry@netapp.com>
    Thanks Bob... I'll make it a DPDT and use the second pole for a nag-light indicating the x-feed switch is closed. Great design. Thanks for saving us a bunch of work. Phil -----Original Message----- From: Robert L. Nuckolls, III [mailto:nuckolls.bob@aeroelectric.com] Sent: Wednesday, January 06, 2010 10:32 AM Subject: RE: AeroElectric-List: Z-14 Switch Combos <nuckolls.bob@aeroelectric.com> At 10:19 AM 1/6/2010, you wrote: <Phil.Perry@netapp.com> > >Hey Bob, > >It looks like the crossfeed switch doubles as a starter switch in your >diagram, is that correct? Yes . . . it's spring loaded out of the start position. It offers automatic closure of the cross-feed contactor during start. >I'm planning on going with a push button to start, so I'll probably >modify the setup slightly. But just want to make sure I'm reading it >correctly. Then the cross-feed switch can be SPST. Bob . . .




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