---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 06/16/16: 16 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:38 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (William Greenley) 2. 08:56 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (Robert L. Nuckolls, III) 3. 09:26 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (Carlos Trigo) 4. 09:26 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (William Greenley) 5. 10:42 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (Robert L. Nuckolls, III) 6. 10:47 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (Robert L. Nuckolls, III) 7. 11:11 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (Justin Jones) 8. 11:33 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (William Greenley) 9. 11:34 AM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (William Greenley) 10. 11:42 AM - Re: Re: Review request for RV-9 Electrical System (G3X, ... (ARGOLDMAN@aol.com) 11. 01:18 PM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (Robert L. Nuckolls, III) 12. 01:31 PM - Re: Re: Review request for RV-9 Electrical System (G3X, ... (Robert L. Nuckolls, III) 13. 01:45 PM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (William Greenley) 14. 03:48 PM - Re: Re: Review request for RV-9 Electrical System (G3X... (ARGOLDMAN@aol.com) 15. 06:58 PM - Re: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) (Robert L. Nuckolls, III) 16. 07:27 PM - Re: Re: Review request for RV-9 Electrical System (G3X... (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:38:41 AM PST US From: "William Greenley" Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) One place on my Cessna I have found a breaker VERY useful is the 12v power port (aka Cigarette lighter). Sometimes items with too big a draw get plugged in and blow the breaker, remove item, reset, and can still use other items in flight. From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Wednesday, June 15, 2016 4:11 PM Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 02:14 PM 6/14/2016, you wrote: OK, I think I see your point on not needing breakers and going with fuses but I'm not 100% there yet. For my personal sense of comfort I'd like to have items on the endurance bus on breakers. Does this seem like a reasonable compromise? Compromise for what? If a breaker ever opens it means something is broke . . . and that something threatens to set a wire on fire. You want to give it a second chance? What items in your airplane are high priority equipment for comfortable termination of flight? From that list of items, how many of them can fail in ways that do not open a breaker? I can tell you that the vast majority of equipment failures never open a breaker . . . if that item is so necessary/useful that you're worried about being able to reclose a breaker, then you'd better have a plan-b . . . a back up for when the system decides to take a vacation. It allows me to load-shed even further by pulling breakers if needed and uses much fewer breakers and panel space. Thoughts? Load shed? What's the e-bus for? The LAST thing you should be doing in flight is running any kind of mental gymnastics calculated to reduce risks of dealing with some kind of failure. ALL such things are done at THIS phase of your design and fabrication. Should a necessary item go T.U. then you go to plan-b. If the item is not necessary, then there is no plan-B. The idea behind the e-bus is to do a two-switch load shed that either (1) does not overtax an SD-8 or (2) produces a KNOWN endurance value running battery only based on periodic capacity checks of your battery. Messing with any breaker or fuse in flight is a demonstration of poor planning that should have been managed during THIS phase of your project's development. Put the fuse blocks out of sight and out of mind. Deal with system difficulties as a pilot with a plan . . . not an in-flight diagnostician and maintenance technician. Bob . . . ________________________________ Message 2 _____________________________________ Time: 08:56:12 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 08:36 AM 6/16/2016, you wrote: >One place on my Cessna I have found a breaker VERY useful is the 12v >power port (aka Cigarette lighter). Sometimes items with too big a >draw get plugged in and blow the breaker, remove item, reset, and >can still use other items in flight. The factory stock 'cigar' lighter? Waaayyyy back when, the folks at the factory decided it was better to call them cigar lighters . . . seems that tobacco smoke particulates were too fine to be captured by the paper air filter for the vacuum driven instruments. We were seeing early demise of gyros flown by pilots who smoked while airborne . . . Somebody got the idea that this problem might be helped if we started calling them cigar lighters . . . fatter smoke particles . . . Emacs! In any case, your anecdote is the corollary to outlets in your house where a branch circuit is shared by other outlets with wildly variable total loads. Too many hot-dog cookers, microwaves, and pizza ovens plugged in at the same time may pop a breaker. Fuses and breakers intended to supply system hardware should not be shared with any other system . . . unless loss of ALL systems is a low, acceptable risk condition. The founding philosophy for bus structures with independently protected feeders is ISOLATION between systems such that no fault brings down more than the affected system. How much stuff do you plug into the cigar lighter? On many Cessnas of the 1970 time frame the cigar lighter was powered through a 20A fuse and later a 10A breaker. 10A is a LOT of 'stuff' to run from such a connector Emacs! Bob . . . ________________________________ Message 3 _____________________________________ Time: 09:26:21 AM PST US From: Carlos Trigo Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) Bob With due respect, what William meant to say is that, against the anti-CB ten dency of you and many people in this forum, he has found a particular circui t (the "cigar" lighter-type power port) where a circuit breaker is the prefe rred method (instead of a fuse) Regards Carlos Enviado do meu iPhone No dia 16/06/2016, =C3-s 16:53, Robert L. Nuckolls, III escreveu: > At 08:36 AM 6/16/2016, you wrote: >> One place on my Cessna I have found a breaker VERY useful is the 12v powe r port (aka Cigarette lighter). Sometimes items with too big a draw get plug ged in and blow the breaker, remove item, reset, and can still use other ite ms in flight. > > The factory stock 'cigar' lighter? Waaayyyy back when, > the folks at the factory decided it was better to call > them cigar lighters . . . seems that tobacco smoke > particulates were too fine to be captured by the > paper air filter for the vacuum driven instruments. > We were seeing early demise of gyros flown by > pilots who smoked while airborne . . . > > Somebody got the idea that this problem might be > helped if we started calling them cigar lighters . . . > fatter smoke particles . . . > > > <6bca009.jpg> > > > In any case, your anecdote is the corollary to > outlets in your house where a branch circuit > is shared by other outlets with wildly variable > total loads. Too many hot-dog cookers, microwaves, > and pizza ovens plugged in at the same time > may pop a breaker. > > Fuses and breakers intended to supply system > hardware should not be shared with any other > system . . . unless loss of ALL systems is > a low, acceptable risk condition. The founding > philosophy for bus structures with independently > protected feeders is ISOLATION between systems > such that no fault brings down more than the > affected system. > > How much stuff do you plug into the cigar > lighter? On many Cessnas of the 1970 time frame > the cigar lighter was powered through a 20A fuse > and later a 10A breaker. 10A is a LOT of 'stuff' > to run from such a connector > > <6bca066.jpg> > > > > Bob . . . ________________________________ Message 4 _____________________________________ Time: 09:26:26 AM PST US From: "William Greenley" Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) Thanks for the info, I need to check the wiring et al on mine, it only has a 5A breaker. Which is easy to blow. Just assumed it was correct. From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Thursday, June 16, 2016 11:54 AM Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 08:36 AM 6/16/2016, you wrote: One place on my Cessna I have found a breaker VERY useful is the 12v power port (aka Cigarette lighter). Sometimes items with too big a draw get plugged in and blow the breaker, remove item, reset, and can still use other items in flight. The factory stock 'cigar' lighter? Waaayyyy back when, the folks at the factory decided it was better to call them cigar lighters . . . seems that tobacco smoke particulates were too fine to be captured by the paper air filter for the vacuum driven instruments. We were seeing early demise of gyros flown by pilots who smoked while airborne . . . Somebody got the idea that this problem might be helped if we started calling them cigar lighters . . . fatter smoke particles . . . Emacs! In any case, your anecdote is the corollary to outlets in your house where a branch circuit is shared by other outlets with wildly variable total loads. Too many hot-dog cookers, microwaves, and pizza ovens plugged in at the same time may pop a breaker. Fuses and breakers intended to supply system hardware should not be shared with any other system . . . unless loss of ALL systems is a low, acceptable risk condition. The founding philosophy for bus structures with independently protected feeders is ISOLATION between systems such that no fault brings down more than the affected system. How much stuff do you plug into the cigar lighter? On many Cessnas of the 1970 time frame the cigar lighter was powered through a 20A fuse and later a 10A breaker. 10A is a LOT of 'stuff' to run from such a connector Emacs! Bob . . . ________________________________ Message 5 _____________________________________ Time: 10:42:11 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 11:25 AM 6/16/2016, you wrote: >Bob > >With due respect, what William meant to say is that, against the >anti-CB tendency of you and many people in this forum, he has found >a particular circuit (the "cigar" lighter-type power port) where a >circuit breaker is the preferred method (instead of a fuse) No argument . . . Cessna went away from a 20A inline fuse to a 10A breaker no doubt 'cause folks were popping the fuse a lot. The point being offered is that a well considered array of loads to one's airplane will never nuisance pop a breaker or fuse. Knowing loads and limitations before 'hooking up' is a good thing to do . . . Bob . . . ________________________________ Message 6 _____________________________________ Time: 10:47:14 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 11:25 AM 6/16/2016, you wrote: >Thanks for the info, I need to check the wiring et al on mine, it >only has a 5A breaker. Which is easy to blow. Just assumed it was correct. Interesting! This is a 14 or 28v airplane? Check your maintenance manual for the factory installed part data . . . the drawing I posted was for a group of 172's. Given that all the single engine products were wired by one electrical group, features in one model tended to ripple across the spectrum of products . . . but that's not a hard/fast rule. If you don't have a manual, give me the s/n of the airplane and I'll see if my 'contacts' can shoot us the drawing. Bob . . . ________________________________ Message 7 _____________________________________ Time: 11:11:41 AM PST US From: Justin Jones Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) Keep in mind that the circuit breaker needs to be matched to the appropriate wire size. The circuit protection is there to protect the wire, not the loa d. First assess how much current the load will pull. Then choose an appropriat e sized wire and circuit protection. Justin > On Jun 16, 2016, at 08:25, William Greenley wrote: > > Thanks for the info, I need to check the wiring et al on mine, it only has a 5A breaker. Which is easy to blow. Just assumed it was correct. > > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelect ric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III > Sent: Thursday, June 16, 2016 11:54 AM > To: aeroelectric-list@matronics.com > Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical Sys tem (G3X, GTN, etc) > > At 08:36 AM 6/16/2016, you wrote: > > One place on my Cessna I have found a breaker VERY useful is the 12v power port (aka Cigarette lighter). Sometimes items with too big a draw get plugg ed in and blow the breaker, remove item, reset, and can still use other item s in flight. > > The factory stock 'cigar' lighter? Waaayyyy back when, > the folks at the factory decided it was better to call > them cigar lighters . . . seems that tobacco smoke > particulates were too fine to be captured by the > paper air filter for the vacuum driven instruments. > We were seeing early demise of gyros flown by > pilots who smoked while airborne . . . > > Somebody got the idea that this problem might be > helped if we started calling them cigar lighters . . . > fatter smoke particles . . . > > > > > > In any case, your anecdote is the corollary to > outlets in your house where a branch circuit > is shared by other outlets with wildly variable > total loads. Too many hot-dog cookers, microwaves, > and pizza ovens plugged in at the same time > may pop a breaker. > > Fuses and breakers intended to supply system > hardware should not be shared with any other > system . . . unless loss of ALL systems is > a low, acceptable risk condition. The founding > philosophy for bus structures with independently > protected feeders is ISOLATION between systems > such that no fault brings down more than the > affected system. > > How much stuff do you plug into the cigar > lighter? On many Cessnas of the 1970 time frame > the cigar lighter was powered through a 20A fuse > and later a 10A breaker. 10A is a LOT of 'stuff' > to run from such a connector > > > > > > > Bob . . . ________________________________ Message 8 _____________________________________ Time: 11:33:52 AM PST US From: "William Greenley" Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) The plane is a 1956/57 14V 172, its serial # is 29628 which is supposed to by 1957, but it has some 1956 features like fuel vent on top of the wing. In the years since 1957 someone had replaced the 'cigar' lighter fuse with a 5A circuit breaker, which with a 14v plane is not very many watts. I have the original parts catalogs, but cannot find fuse information in it, and back then the regular manuals were very limited in detail. Bill From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Thursday, June 16, 2016 1:46 PM Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 11:25 AM 6/16/2016, you wrote: Thanks for the info, I need to check the wiring et al on mine, it only has a 5A breaker. Which is easy to blow. Just assumed it was correct. Interesting! This is a 14 or 28v airplane? Check your maintenance manual for the factory installed part data . . . the drawing I posted was for a group of 172's. Given that all the single engine products were wired by one electrical group, features in one model tended to ripple across the spectrum of products . . . but that's not a hard/fast rule. If you don't have a manual, give me the s/n of the airplane and I'll see if my 'contacts' can shoot us the drawing. Bob . . . ________________________________ Message 9 _____________________________________ Time: 11:34:35 AM PST US From: "William Greenley" Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) That is my plan, trace all wiring and analyze connections. From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Justin Jones Sent: Thursday, June 16, 2016 2:10 PM Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) Keep in mind that the circuit breaker needs to be matched to the appropriate wire size. The circuit protection is there to protect the wire, not the load. First assess how much current the load will pull. Then choose an appropriate sized wire and circuit protection. Justin On Jun 16, 2016, at 08:25, William Greenley wrote: Thanks for the info, I need to check the wiring et al on mine, it only has a 5A breaker. Which is easy to blow. Just assumed it was correct. From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Thursday, June 16, 2016 11:54 AM Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 08:36 AM 6/16/2016, you wrote: One place on my Cessna I have found a breaker VERY useful is the 12v power port (aka Cigarette lighter). Sometimes items with too big a draw get plugged in and blow the breaker, remove item, reset, and can still use other items in flight. The factory stock 'cigar' lighter? Waaayyyy back when, the folks at the factory decided it was better to call them cigar lighters . . . seems that tobacco smoke particulates were too fine to be captured by the paper air filter for the vacuum driven instruments. We were seeing early demise of gyros flown by pilots who smoked while airborne . . . Somebody got the idea that this problem might be helped if we started calling them cigar lighters . . . fatter smoke particles . . . In any case, your anecdote is the corollary to outlets in your house where a branch circuit is shared by other outlets with wildly variable total loads. Too many hot-dog cookers, microwaves, and pizza ovens plugged in at the same time may pop a breaker. Fuses and breakers intended to supply system hardware should not be shared with any other system . . . unless loss of ALL systems is a low, acceptable risk condition. The founding philosophy for bus structures with independently protected feeders is ISOLATION between systems such that no fault brings down more than the affected system. How much stuff do you plug into the cigar lighter? On many Cessnas of the 1970 time frame the cigar lighter was powered through a 20A fuse and later a 10A breaker. 10A is a LOT of 'stuff' to run from such a connector Bob . . . ________________________________ Message 10 ____________________________________ Time: 11:42:02 AM PST US From: ARGOLDMAN@aol.com Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, ... Or you can use a polyfuse. This will remain open until the fault is cured. Of course when there is a fault, it behooves one to register it so that the problem can be corrected. With the temporary overload, when the offending device is removed, in a very short while, the circuit is once again whole. These are used extensively on car windows since when they reach their physical limit the amperage draw goes up and the circuit breaks (when the window stops at its travel end, it is usually a signal to get your hand off of the switch. If you don't, instead of the wiring burning up, the poly fuse opens. Release the switch the polyfuse will again reconnect and if desired you can put the window up or down as you wish. The polyfuse is available in various amperages and cost less than $1 usually. The polyfuse is a thermally actuated device usually buried where the sun don't shine with no indication of circuit breakage (although you can devise a circuit that tells you). AlthoughI know many EABers who use them exclusively, I still use breakers for critical circuits (although probably overkill). I believe polyfuse is a trademark owned by littlefuse or some such company. Rich In a message dated 6/16/2016 11:28:06 A.M. Pacific Daylight Time, wgreenley@gmail.com writes: One place on my Cessna I have found a breaker VERY useful is the 12v power port (aka Cigarette lighter). Sometimes items with too big a draw get plugged in and blow the breaker, remove item, reset, and can still use other items in flight. From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Wednesday, June 15, 2016 4:11 PM Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 02:14 PM 6/14/2016, you wrote: (mailto:fly@bappos.com) > OK, I think I see your point on not needing breakers and going with fuses but I'm not 100% there yet. For my personal sense of comfort I'd like to have items on the endurance bus on breakers. Does this seem like a reasonable compromise? Compromise for what? If a breaker ever opens it means something is broke . . . and that something threatens to set a wire on fire. You want to give it a second chance? What items in your airplane are high priority equipment for comfortable termination of flight? From that list of items, how many of them can fail in ways that do not open a breaker? I can tell you that the vast majority of equipment failures never open a breaker . . . if that item is so necessary/useful that you're worried about being able to reclose a breaker, then you'd better have a plan-b . . . a back up for when the system decides to take a vacation. It allows me to load-shed even further by pulling breakers if needed and uses much fewer breakers and panel space. Thoughts? Load shed? What's the e-bus for? The LAST thing you should be doing in flight is running any kind of mental gymnastics calculated to reduce risks of dealing with some kind of failure. ALL such things are done at THIS phase of your design and fabrication. Should a necessary item go T.U. then you go to plan-b. If the item is not necessary, then there is no plan-B. The idea behind the e-bus is to do a two-switch load shed that either (1) does not overtax an SD-8 or (2) produces a KNOWN endurance value running battery only based on periodic capacity checks of your battery. Messing with any breaker or fuse in flight is a demonstration of poor planning that should have been managed during THIS phase of your project's development. Put the fuse blocks out of sight and out of mind. Deal with system difficulties as a pilot with a plan . . . not an in-flight diagnostician and maintenance technician. Bob . . . ________________________________ Message 11 ____________________________________ Time: 01:18:33 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 01:32 PM 6/16/2016, you wrote: >The plane is a 1956/57 14V 172, its serial # is 29628 which is >supposed to by 1957, but it has some 1956 features like fuel vent on >top of the wing. In the years since 1957 someone had replaced the >'cigar' lighter fuse with a 5A circuit breaker, which with a 14v >plane is not very many watts. I have the original parts catalogs, >but cannot find fuse information in it, and back then the regular >manuals were very limited in detail. Yeah . . . my tour of duty didn't begin for another 8 years. Lots of changes took place on documentation. Did this airplane originally have all fuses on the bus . . . with holders that look like this? Emacs! They were already using breakers by the time I got there but I don't recall when the change took place. Your breaker protected cigar lighter may well be an after-market mod . . . in which case you're not on really thin ice to simply replace the breaker with a 10A device and insure that connecting wires are 18AWG or larger. Bob . . . ________________________________ Message 12 ____________________________________ Time: 01:31:22 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, ... At 01:41 PM 6/16/2016, you wrote: >Or you can use a polyfuse. This will remain open until the fault is cured. > >Of course when there is a fault, it behooves one to register it so >that the problem can be corrected. Problem with Polyfuses is how do you mount them in an airplane? They have to be free to get hot . . . that's what triggers their current reduction behavior. They're designed to solder onto an etched circuit board. http://tinyurl.com/zevs7xy Mounting them in a mechanically robust configuration while letting the body of the device hang out in the breeze is problematic. I was tasked twice to look at Polyfuses at Beech over the years . . . they just didn't lend themselves to airframe integration. Inside some black box was okay . . . but we just couldn't figure a way to use them economically on the bus structures. Bob . . . ________________________________ Message 13 ____________________________________ Time: 01:45:52 PM PST US Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) From: William Greenley That is exactly what the fuse holders look like, and yes the cb looks lik a later mod. On Jun 16, 2016 4:26 PM, "Robert L. Nuckolls, III" < nuckolls.bob@aeroelectric.com> wrote: > At 01:32 PM 6/16/2016, you wrote: > > The plane is a 1956/57 14V 172, its serial # is 29628 which is supposed t o > by 1957, but it has some 1956 features like fuel vent on top of the wing. > In the years since 1957 someone had replaced the =98cigar=99 lighter fuse with > a 5A circuit breaker, which with a 14v plane is not very many watts. I ha ve > the original parts catalogs, but cannot find fuse information in it, and > back then the regular manuals were very limited in detail. > > > Yeah . . . my tour of duty didn't begin > for another 8 years. Lots of changes took > place on documentation. > > Did this airplane originally have all fuses > on the bus . . . with holders that look like > this? > > > [image: Emacs!] > > They were already using breakers by the time > I got there but I don't recall when the change > took place. Your breaker protected cigar lighter > may well be an after-market mod . . . in which > case you're not on really thin ice to simply > replace the breaker with a 10A device and insure > that connecting wires are 18AWG or larger. > > > Bob . . . > ________________________________ Message 14 ____________________________________ Time: 03:48:35 PM PST US From: ARGOLDMAN@aol.com Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X... yep make a small PC board with leads coming out. Heat shrink for protection (just small enough to protect and not crush Rich In a message dated 6/16/2016 1:32:16 P.M. Pacific Daylight Time, nuckolls.bob@aeroelectric.com writes: At 01:41 PM 6/16/2016, you wrote: Or you can use a polyfuse. This will remain open until the fault is cured. Of course when there is a fault, it behooves one to register it so that the problem can be corrected. Problem with Polyfuses is how do you mount them in an airplane? They have to be free to get hot . . . that's what triggers their current reduction behavior. They're designed to solder onto an etched circuit board. _http://tinyurl.com/zevs7xy _ (http://tinyurl.com/zevs7xy) Mounting them in a mechanically robust configuration while letting the body of the device hang out in the breeze is problematic. I was tasked twice to look at Polyfuses at Beech over the years . . . they just didn't lend themselves to airframe integration. Inside some black box was okay . . . but we just couldn't figure a way to use them economically on the bus structures. Bob . . . ________________________________ Message 15 ____________________________________ Time: 06:58:31 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X, GTN, etc) At 03:41 PM 6/16/2016, you wrote: >That is exactly what the fuse holders look like, and yes the cb >looks lik a later mod. shucks, you're home free. upsize the breaker and wire as appropriate. we'll never tell. Bob . . . ________________________________ Message 16 ____________________________________ Time: 07:27:51 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Review request for RV-9 Electrical System (G3X... At 05:46 PM 6/16/2016, you wrote: >yep make a small PC board with leads coming out. Heat shrink for >protection (just small enough to protect and not crush But if you 'touch' the sides of the Polyfuse in any way, it takes heat out causing dissipation requirements for transition to 'tripped' to go up. Cool them off very much and they self-destruct never transition and will self destruct. You can't glue them down for vibration resistance. I poked around on Digikey and found this new kid on the PolySwitch block . . . http://tinyurl.com/he3j2jp Emacs! Seems to fit into the standard Mini-ATC fuse holder. Only found the one size. Will carry 8A at 25C but takes as much as 8 seconds at at 40A . . . REALLY slow even for a 10A thermal breaker. I've used these things in surface mount versions to protect ECB traces at sub-amp trips . . . but I don't see that they're yet ready for prime time in power distribution. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.