---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 11/05/10: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 0. 12:15 AM - Reminder (Matt Dralle) 1. 12:52 AM - Re: Z-16 (pestar) 2. 06:25 AM - Re: Re: Battery contactor versus circuit breaker (Robert L. Nuckolls, III) 3. 07:38 AM - Fuselink Link 14/10 AWG connection (Harold Lanfear) 4. 08:40 AM - Re: Fuselink Link 14/10 AWG connection (George, Neal E Capt USAF ACC 505 TRS/DOJ) 5. 10:08 AM - Toggle Switch Failures in Canadian C-152 (Robert L. Nuckolls, III) 6. 10:15 AM - Re: Fuselink Link 14/10 AWG connection (Robert L. Nuckolls, III) 7. 10:45 AM - Re: Fuselink Link 14/10 AWG connection (paul wilson) 8. 11:20 AM - Re: Fuselink Link 14/10 AWG connection (Robert L. Nuckolls, III) 9. 11:21 AM - Re: Adding crowbar to older Z-11 architecture (Robert L. Nuckolls, III) 10. 04:39 PM - Re: Fuselink Link 14/10 AWG connection (paul wilson) 11. 06:04 PM - Covering up the contactors (James Kilford) 12. 10:07 PM - Re: Covering up the contactors (Robert L. Nuckolls, III) ________________________________ Message 0 _____________________________________ Time: 12:15:09 AM PST US From: Matt Dralle Subject: AeroElectric-List: Reminder Dear Listers, A quick reminder that November is the annual List Fund Raiser. The Matronics Lists are 100% member supported and all of the operational costs are provided for my your Contributions during this time of the year. Your personal Contribution makes a big difference and keeps all of the Matronics Email Lists and Forums completely ad-free. Please make your Contribution today to keep these services up and running! http://www.matronics.com/contribution Thank you in advance! Matt Dralle Matronics Email List and Forum Administrator ________________________________ Message 1 _____________________________________ Time: 12:52:04 AM PST US Subject: AeroElectric-List: Re: Z-16 From: "pestar" Go to http://www.narva.com.au/products/browse/relays, they have a range of relays with the diode built in at low cost. I am using them for OV protection as per Bobs diagrams. Yep I know it is down under but the relays are manufactured in Europe. Cheers Peter Armstrong Auckland, New zealand Read this topic online here: http://forums.matronics.com/viewtopic.php?p=318289#318289 ________________________________ Message 2 _____________________________________ Time: 06:25:45 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Battery contactor versus circuit breaker > >It really sounds from what I'm reading that a battery contactor is >the more desirable and "elegant" solution from a number of different >aspects, rather than a circuit breaker purely serving as "automatic" >battery wiring protection. > >I know the diagram was only ever intended as a very rough guide for >the builder, but I can only speculate why it was drawn with a >breaker on the supply side instead of a battery contactor. Most folks skilled at airframe and power plants are not widely read or experienced in electrical systems. While suggested architectures and diagrams are always functional at some level, they almost never embody the best we know how to do nor are they tailored to the builder's mission profile and design goals. It's not uncommon to find 'suggestions' that really stretch the imagination of the reader to deduce the simple-ideas that support the feature's incorporation. Whether or not to go the contactor route is driven by two major considerations. Location of the switching device for convenience of operation and/or power savings when the engine driven power source or battery size is small. A 0.8A contactor current draw is no big deal when a 60A alternator is keeping the lights lit. But when the alternator is good for say 8A or you're trying to extend battery-only operations, elimination of a contactor has benefits. So it isn't a one-size-fits-all thought exercise. Bob . . . ________________________________ Message 3 _____________________________________ Time: 07:38:07 AM PST US From: "Harold Lanfear" Subject: AeroElectric-List: Fuselink Link 14/10 AWG connection I=92m following Bob=92s Z-13/20 circuit and ready to install the 14 AWG fusible link in the 10 AWG feed to the Battery Buss. However, there are no crimp connectors matching both sizes; can I solder this joint or are there better ways? I don=92t have spade and socket terminals to match and hate to make a purchase for just a couple of terminals. Thanks much. ________________________________ Message 4 _____________________________________ Time: 08:40:00 AM PST US Subject: RE: AeroElectric-List: Fuselink Link 14/10 AWG connection From: "George, Neal E Capt USAF ACC 505 TRS/DOJ" Harold - You have several acceptable options. Among them: 1. Solder the 10-ga to 14-ga junctions, support with heat-shrink & cover with fiberglass tube. 2. Strip the 14-ga wire back twice as far as you normally would and fold the stripped end back on itself to better fill the 10-ga crimp connector. Heat-shrink and fiberglass tube as indicated in AEC. neal =================== -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Harold Lanfear Sent: Friday, November 05, 2010 9:26 AM Subject: AeroElectric-List: Fuselink Link 14/10 AWG connection I'm following Bob's Z-13/20 circuit and ready to install the 14 AWG fusible link in the 10 AWG feed to the Battery Buss. However, there are no crimp connectors matching both sizes; can I solder this joint or are there better ways? I don't have spade and socket terminals to match and hate to make a purchase for just a couple of terminals. Thanks much. ________________________________ Message 5 _____________________________________ Time: 10:08:28 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Toggle Switch Failures in Canadian C-152 The C-152 switches cited in the Canadian publication have nothing in common with the failures we've been discussing here on the List in recent years . . . The failure modes we've considered have to do with a riveted construction of the Carling switches that have been used on light airplanes for about 50 years. We've also considered some poor joining (crimps) in the wire grips of terminals. http://www.aeroelectric.com/Mfgr_Data/Switches/Carling/Carling_F-series.pdf Over time, something has changed in materials, design or process that make these devices more vulnerable to loss of contact between the various metallic joints in the current carrying path. All of the numbered features in this figure . . . http://aeroelectric.com/Pictures/Switches/Toggle_Switch_with_Fast-On_Tabs.jpg A number of readers have reported failures in Carling switches with most occurring in the one circuit that generally operates at significant current flow all the time for day and night operations . . . strobes. The failures have generally demonstrated a rise in joint resistance followed by heating exacerbated precipitation of the failure . . . http://www.aeroelectric.com/articles/Anatomy_of_a_Switch_Failure/Anatomy_of_a_Switch_Failure.html The C-152 switches referenced in the article are are smaller and a cut below the Carling, F-series switches we've been discussing. I'm familiar with them but do not know who made them. They ARE a much less expensive switch but I don't recall that they used the riveted construction common to the F-series Carlings. I believe the construction of these switches looks more like this: http://aeroelectric.com/Pictures/Switches/Miniature_Rocker_Cutaway.jpg No rivets, only a pair of moving contacts that get the benefit of some sliding motion that tends to improve contact performance compared to contacts that are simply mashed together. It's interesting that this design REDUCES number of metallic joints in current path from 10 down to 5. Pretty slick little switch. I captured the Canadian failure analysis and started to sift if for salient data and conclusions. http://www.aeroelectric.com/articles/C152_landing_light_switch_failures.pdf This document is only a small cut above the typical dark-n-stormy night story found in legacy aviation rags. These guys did a electron microscope and spectrometer analysis of the gooey stuff on the switch to decide that it was probably dust and drippings from a fitting on the oil pressure gage above. Availability and applications of whippy tools does not automatically translate into better conclusions and remedial actions. As soon as the writer mentioned "no DC ratings", commented on circuit breaker performance, and iced the cake with recommendations for a 70A rated panel mounted switch, the value of their subsequent analysis stepped off into the weeds. See: http://www.aeroelectric.com/articles/Switch_Ratings.pdf The effects have rippled throughout the aviation community. http://www.cessna.org/public/saib/docs/saib-ce-09-42.pdf http://www.cessna170.org/forums/download/file.php?id=1199&sid=8c7275731a2108c3bdd961d763760192 http://n631s.blogspot.com/2009/09/landing-light-switches.html Bottom line was that the switches used in these applications (whether the C-150/152 mini rockers or the larger Carling F series) have a SERVICE LIFE that is driven more by CHRONOLOGICAL AGE and ENVIRONMENTAL CONDITIONS (dripping oil, dust, moisture, etc) combined with a LACK OF ACTIVITY that tends to burn away corrosion and contaminants. Would the failure have been prevented by installation of a superswitch? http://aeroelectric.com/Pictures/Switches/Toggle_Switch_with_Mold-Captured_Terminals.jpg It might have taken longer . . . but the switch would eventually wear out and need replacement. The mode of failure would probably have been less exciting. But these switches are 10x the price of the devices used in tens of thousands of production airplanes with a very low rate of spectacular failures. Light GA aircraft place unusual demands on switches. I've been suggesting for nearly 20 years that the OBAM aircraft owner/operator simply shotgun a new set of switches into the airplane every 5 years or so. Costs $50 in parts and a couple hours work. Can't do that on a TC aircraft for less than an indentured servant contract on your first born. Nonetheless, the spectacular failure of this 20+ year old switch covered with greasy dust was determined to be "inadequate to the design". For every one that HAS failed, there are thousands of switches that have NOT failed. I personally witnessed extensive "life cycle testing" of new switches in Cessna's lab . . . a landing light was switched on/off for thousands of times before any new switch was considered "adequate to the design". But like all laboratory testing adventures, stresses on the device during testing had little relevancy to stresses experienced in service. Just how did these investigators EXPECT a switch to fail? Some switches may fail passive but quite often, they get hot and smell bad. This report suggests that a device "adequate to the design" would last until the airframe was scrapped or at least not get hot and smell bad. Sorry my friend but it just doesn't work that way. Bottom line is that the vast majority of switch failures being reported to those-who-know-more-about- airplanes-than-we-do have reached end of life never fully explored and recognized by the appropriate recommendations in a service manual. The report was also noteworthy in citing lack of maintenance that did not at least clean up and fix leaks of oil above the switch that most certainly exacerbated an otherwise "normal" failure. Well guess what? Cessna responded in the only way they COULD. Limit service life to the high current switches to FOUR years . . . not flight hours but calendar service life. Something that could and should have happened 30 years ago. How should WE react to this? Periodic replacement of highly stressed switches is a good idea. Cheap, easy, effective. Also, fix oil drips and clean up the mess . . . but YOU guys do that anyhow . . . right? Use relays to buffer the current demands on panel mounted switches? Good . . . but it drives up parts count and cost of ownership. The switch WILL probably run to life of the airframe while you still do periodic replacement of relays. A simple, low cost preventative maintenance program based on understanding is the best way to keep these things from happening in your airplane . . . like periodic replacement of highly stressed switches. Having said all that, know that the failures we've discussed recently about switches and terminals used to wire those switches are a completely separate set of events and solutions unrelated to the Canadian activity that seeded this thread. Bob . . . ________________________________ Message 6 _____________________________________ Time: 10:15:29 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Fuselink Link 14/10 AWG connection At 09:26 AM 11/5/2010, you wrote: >I'm following Bob's Z-13/20 circuit and ready to install the 14 AWG >fusible link in the 10 AWG feed to the Battery Buss. However, there >are no crimp connectors matching both sizes; can I solder this joint >or are there better ways? I don't have spade and socket terminals >to match and hate to make a purchase for just a couple of >terminals. Thanks much. Suggest you use a MAX 30 fuse and mating in-line fuse holder Emacs! available from most big-box auto parts stores. Bob . . . ________________________________ Message 7 _____________________________________ Time: 10:45:32 AM PST US From: paul wilson Subject: Re: AeroElectric-List: Fuselink Link 14/10 AWG connection NAPA is now selling the kind Bob likes. They have the double metal that allows the insulation to be crimped. You need to crimp twice to get both the wire and the insulation. They pass my pull test and grab the 1/4" spade plenty hard. Try them before you buy the AMP ones. So far just red and blue not yellow where I live. Check your store If they have the yellow you will be good to go with a little heat shrink. Maybe Bob will give us and evaluation?? HINT. Paul ============== At 07:26 AM 11/5/2010, you wrote: >I'm following Bob's Z-13/20 circuit and ready to install the 14 AWG >fusible link in the 10 AWG feed to the Battery Buss. However, there >are no crimp connectors matching both sizes; can I solder this joint >or are there better ways? I don't have spade and socket terminals >to match and hate to make a purchase for just a couple of >terminals. Thanks much. ________________________________ Message 8 _____________________________________ Time: 11:20:31 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Fuselink Link 14/10 AWG connection At 12:02 PM 11/5/2010, you wrote: > >NAPA is now selling the kind Bob likes. They have the double metal >that allows the insulation to be crimped. You need to crimp twice to >get both the wire and the insulation. They pass my pull test and >grab the 1/4" spade plenty hard. Try them before you buy the AMP >ones. So far just red and blue not yellow where I live. Check your >store If they have the yellow you will be good to go with a little heat shrink. > >Maybe Bob will give us and evaluation?? HINT. Hmmmm . . . do you have a manufacturer and part number by chance? We might be able to learn a lot from the manufacturer's data. Bob . . . ________________________________ Message 9 _____________________________________ Time: 11:21:23 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Adding crowbar to older Z-11 architecture At 04:33 PM 11/4/2010, you wrote: > >I have been flying for several years with Z-11 (no alternator OV >disc. contactor) and an internally regulated alternator. I would >like to know whether the simple and inexpensive step of installing a >crowbar OV module as in Z-24 will provide OV protection. I have read >Bob's article on load dump damage and I am able to turn off my >alternator with the panel "OFF/BATT/ON" switch. >My thanks to Bob or anyone else who can answer my question. The problem with adding ov protection for internally regulated alternators is that there are failure modes that cannot be controlled through the small wire. So yes, some form of b-lead disconnect is called for and Z-24 is one way to go about it. The load dump thing is a bit of a red herring . . . first, there's no NEED to flip the alternator on/off during normal, loaded operations. Second, any IR alternator worth it's salt will withstand a worst case load dump many times in a row. See revision 12 chapter on engine driven power sources in the 'Connection. Bob . . . ________________________________ Message 10 ____________________________________ Time: 04:39:19 PM PST US From: paul wilson Subject: Re: AeroElectric-List: Fuselink Link 14/10 AWG connection I am 1000 miles away from my shop, but I have a package of the new style butt connectors in my truck. NAPA P/N 784331. They are reds tranlucent plastic and have the extra metal extension. I use several rachet crimpers and they all give a good result with these things. Takes 2 crimps with my crimpers to grab theinsulation. Branded by Balkamp (a NAPA house brand). Made In Taiwan The other stuff in my truck are the cheepe 3M automotive stuff you are fanmiliar with and they will not grab the insulation. However they do give the soild crimp like your AMP tests. Mabe the attached pic will reveal something? At 11:17 AM 11/5/2010, you wrote: > > >At 12:02 PM 11/5/2010, you wrote: >> >>NAPA is now selling the kind Bob likes. They have the double metal >>that allows the insulation to be crimped. You need to crimp twice >>to get both the wire and the insulation. They pass my pull test and >>grab the 1/4" spade plenty hard. Try them before you buy the AMP >>ones. So far just red and blue not yellow where I live. Check your >>store If they have the yellow you will be good to go with a little heat shrink. >> >>Maybe Bob will give us and evaluation?? HINT. > > Hmmmm . . . do you have a manufacturer and part > number by chance? We might be able to learn a > lot from the manufacturer's data. > > > Bob . . . ________________________________ Message 11 ____________________________________ Time: 06:04:55 PM PST US Subject: AeroElectric-List: Covering up the contactors From: James Kilford Gents, I have three contactors mounted on the engine side of the firewall, along with a battery. Everything else (regulator, busses, etc.) is inside the cabin. Is there any value in covering up my contactors, or are they alright as they are? Many thanks, James ________________________________ Message 12 ____________________________________ Time: 10:07:27 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Covering up the contactors At 08:01 PM 11/5/2010, you wrote: > >Gents, > >I have three contactors mounted on the engine side of the firewall, >along with a battery. Everything else (regulator, busses, etc.) is >inside the cabin. Is there any value in covering up my contactors, or >are they alright as they are? Here's the firewall of an A36 Bonanza. http://aeroelectric.com/Pictures/Wiring_Technique/A36_Firewall_A.jpg http://aeroelectric.com/Pictures/Wiring_Technique/A36_Firewall_B.jpg with contactors, fuseblocks, current limiters, etc hung out in behind Continental and everybody. I think your electro-whizzies will be fine without extra-ordinary cover. 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