---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 04/08/13: 9 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:38 AM - Re: Butt Splice for #4 wire (johngoodman) 2. 06:48 AM - Re: Re: Butt Splice for #4 wire (Bill Bradburry) 3. 06:54 AM - Re: Butt Splice for #4 wire (johngoodman) 4. 07:56 AM - Re: Encapsulating connectors (Quest. for Bob) (Ralph Finch) 5. 10:05 AM - Charging System Debug steps and success... (Steve Stearns) 6. 11:13 AM - Re: Re: Butt Splice for #4 wire (Robert L. Nuckolls, III) 7. 03:37 PM - Re: Butt Splice for #4 wire (johngoodman) 8. 06:34 PM - Re: Butt Splice for #4 wire (Chris) 9. 07:46 PM - Re: Charging System Debug steps and success... (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:38:52 AM PST US Subject: AeroElectric-List: Re: Butt Splice for #4 wire From: "johngoodman" Bob, It's #4 welding wire. I have access to about 18" of it before it passes behind the engine to the alternator. I get what you are saying - don't put a butt splice close to the terminal. I worked on it yesterday and the break was very close to the terminal. I was able to put a new terminal on, losing only an inch or so of wire. I had to make a minor reroute change, but made it fit. My biggest issue was keeping it away from the exhaust pipes. I got it 2" away from the pipes and put a leftover piece of firesleeve on it. My biggest surprise was how the cable fatigued so fast. Obviously, engine vibration took it's toll. John PS: I like your new book being bound, but I still like the ability to remove a page for immediate reference. I keep both copies at the hangar. -------- #40572 Phase One complete and flying. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=398134#398134 ________________________________ Message 2 _____________________________________ Time: 06:48:55 AM PST US From: Bill Bradburry Subject: Re: AeroElectric-List: Re: Butt Splice for #4 wire John, Are you saying that engine vibration caused a metal fatigue break in #4 welding wire while you were flying off your Phase 1? Bill B On 4/8/2013 9:37 AM, johngoodman wrote: > > Bob, > It's #4 welding wire. I have access to about 18" of it before it passes behind the engine to the alternator. I get what you are saying - don't put a butt splice close to the terminal. > I worked on it yesterday and the break was very close to the terminal. I was able to put a new terminal on, losing only an inch or so of wire. I had to make a minor reroute change, but made it fit. My biggest issue was keeping it away from the exhaust pipes. I got it 2" away from the pipes and put a leftover piece of firesleeve on it. > > My biggest surprise was how the cable fatigued so fast. Obviously, engine vibration took it's toll. > John > PS: I like your new book being bound, but I still like the ability to remove a page for immediate reference. I keep both copies at the hangar. > > -------- > #40572 Phase One complete and flying. > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=398134#398134 > > ________________________________ Message 3 _____________________________________ Time: 06:54:54 AM PST US Subject: AeroElectric-List: Re: Butt Splice for #4 wire From: "johngoodman" [quote="bbradburry(at)bellsouth.n"]John, Are you saying that engine vibration caused a metal fatigue break in #4 welding wire while you were flying off your Phase 1? Bill B On 4/8/2013 9:37 AM, johngoodman wrote: [quote] Bill, No, I've been flying for almost 2 years. The wire was unsupported for the last 7" to 9" and I figure it was like a hand shake that wouldn't stop.... John -------- #40572 Phase One complete and flying. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=398139#398139 ________________________________ Message 4 _____________________________________ Time: 07:56:03 AM PST US From: Ralph Finch Subject: Re: AeroElectric-List: Encapsulating connectors (Quest. for Bob) Sorry, I meant adhesive of course. You and others correctly interpreted my intent and I got lots of great answers... Thanks everybody, Ralph On Sun, Apr 7, 2013 at 9:57 AM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > > Did you mean to say 'connector' or 'adhesive'? > * * > > ________________________________ Message 5 _____________________________________ Time: 10:05:54 AM PST US From: Steve Stearns Subject: AeroElectric-List: Charging System Debug steps and success... Greetings All, From time-to-time people have posted assorted problems, and gotten answers to, charging system issues. Many of these are of the wandering or oscillating voltage nature. As my charging system (LongEz, externally regulator "ford-style" charging with regulator and battery in the nose) developed an oscillating attitude I had the "opportunity" to collect, review and then apply the information Bob has generously provided and thought an overview might prove useful for the next guy down the road. I'll start with key summary points for those who don't have the current need or desire to read through the details. My symptoms were an oscillating (2 - 6 Hz maybe?) charging voltage visible with the old (WesTach) panel meter. It was sufficient to pop the over-voltage crowbar once. It might also be related to an transient undervoltage alarm I got once. After isolating the problem, I fixed it by replacing the store-bought regulator connector (which had pig-tails, the bad connection was on the factory-made regulator +V crimp) with good-quality Fast-ons direct to the regulator. This dropped the alternator B+ to regulator V+ resistance from 528mOhms to ~140mOhms which fixed the problem. btw: the 140 ohms, which is still higher than I would like, seems to be roughly evenly shared by the fuse-link, breaker and switch (and associated wiring). The details and references for "the next guy": The debug strategy was to start by checking the resistance (using techniques appropriate for milliohm measurments), without doing any disconnecting of the current loop path from alternator B+ to the regulator and then back from the regulator ground (i.e. case) to the alternator ground (i.e. case). My plan was to keep dividing the problem in half to minimize debug time (i.e. binary search). I wanted to do as much testing as I could without taking anything apart as I didn't want to inadvertently change the problem (i.e. wiggle something and have the problem go away...) In the case that no problems were uncovered via the milliohm measurements, I then planned to follow Bob's charging component problem isolation technique which is in chapter 3 of the Aeroelectric connection book. This involves making measurements while the engine is running but I didn't need go to that step and I certainly didn't want to start there. For lots of charging system background and debug information, search Bob's site (www.aeroelectric.com) for "charging" and ignore all the stuff on plug-in-the-wall battery chargers. Bob has written articles and has product related to making good milliohm measurements using an applied current. I prefer having the current source (whether a bench supply or other similar to Bob's milliohm probes) separate rather than combining it with the volt-meter probes. Also, as Bob has covered in his articles, you don't need a regulated-to-a-known-value current source. It suffices to have an unregulated current source (like a D-cell, in a pinch) if you are using a second meter to measure the current. For more information on accurate milliohm measurements, search Bob's site for "milliohm". I conceptually divided the loop in half (ground side vs power side) and picked the ground side first. I put a current source (bench supply with an accurate current limit set to 1A (and set the voltage limit to be 2V though I didn't expect it to ever run in voltage mode regulation)) between the alternator case and the regulator case (which, on my LongEz is the length of the entire aircraft). I then measured the voltage (using separate wires) between the two cases and got 33.9mV which, at one amp, means 33.9mOhms. This is well below the ~200mOhms threshold area of concern (per Bob's annotations contained in "Know_Your_Charging_System.pdf"). Therefore the problem is in the V+ side. I repeated this on the V+ side which is a little bit trickier to measure as the "master" progressive switch needs to be in the "Alternator on" position which can add more currents to deal with (though, it turns out, not much). With the switch on, I measured the voltage from alternator B+ to regulator V+ both with the current source connected, and not connected. The value I care about is the connected value minus the not connected value. (though it still applies, I won't repeat this detail from now on). I measured 528mV (=528mOhms) which is well above the 200mOhm area of concern. So I've identified one (but maybe only the first?, it turned out to be only) problem. I then listed all (well, sort of, I didn't list both side of each wire...) of the connections between Alternator B+ and regulator V+. For me, starting from B+: Near side of load-meter shunt, near side of ANL, near side of fuse-link, near side of over-voltage breaker, nearside of alternator switch, V+ at the regulator. I kept the current source running between B+ on the alternator and regulator V+ (no reason to move it) and picked the point in the middle (near side ANL), B+ to near side ANL was only 11mV (=11mOhms). I continued the divide (roughly in half) and conquer approach (continuing to measure from B+ to my point of interest) which led me quickly to the crimp at the regulator. In the future I *might* start by measuring any connections I didn't personally make (of which there are very very few) before switching to the more disciplined binary search approach. In this case I would have gotten lucky but, in truth, it would not have saved much time. The time was spent going through Bob's articles and developing a plan. The execution of the plan went very fast. Repair and run-up test showed success. Specific Bob articles I found helpful (in addition to those on milliohm measurement): Know_Your_Charging_System.pdf 03_Alternator_12A2.pdf (i.e. the current chapter 3 in the aeroelectric connection, start at page 3-7 for debug info) Happy debugging! Steve Stearns Boulder/Longmont, Colorado Restoring (since 1/07) and flying again (8/11!): N45FC O235 Longeze Cothern/Friling CF1 (~1000 Hrs) Flying (since 9/86): N43732 A65 Taylorcraft BC12D ________________________________ Message 6 _____________________________________ Time: 11:13:50 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Butt Splice for #4 wire At 08:37 AM 4/8/2013, you wrote: Bob, It's #4 welding wire. I have access to about 18" of it before it passes behind the engine to the alternator. I get what you are saying - don't put a butt splice close to the terminal. I worked on it yesterday and the break was very close to the terminal. I was able to put a new terminal on, losing only an inch or so of wire. I had to make a minor reroute change, but made it fit. My biggest issue was keeping it away from the exhaust pipes. I got it 2" away from the pipes and put a leftover piece of firesleeve on it. My biggest surprise was how the cable fatigued so fast. Obviously, engine vibration took it's toll. Did you put heat-shrink over the wire-grip and wire? More specifically, double-walled heatshrink . . . very stiff? Whether crimped or soldered, stranded wires experience a stress concentration at the transition point from solid to stranded. When we sold terminal kits for installation by soldering http://tinyurl.com/ct36xen the kit included a 2" piece of double-wall heatshrink to provide insulation support. John PS: I like your new book being bound, but I still like the ability to remove a page for immediate reference. I keep both copies at the hangar. Many builders have expressed a preference for the 3-ring format. You can take your bound book to a copy/print shop like Kinkos and have it drilled for ring binder. They also have a paper cutter that will shear off the spine. Cut the spine off first so that the drilled holes have the right edge margins. Do you still have the terminal that broke off? I'd like to have it if you could see fit to mail it to me. Bob . . . ________________________________ Message 7 _____________________________________ Time: 03:37:07 PM PST US Subject: AeroElectric-List: Re: Butt Splice for #4 wire From: "johngoodman" > Did you put heat-shrink over the wire-grip and > wire? More specifically, double-walled > heatshrink . . . very stiff? > > Whether crimped or soldered, stranded wires > experience a stress concentration at the > transition point from solid to stranded. When > we sold terminal kits for installation > by soldering > > http://tinyurl.com/ct36xen > > the kit included a 2" piece of double-wall > heatshrink to provide insulation support. > Bob, I'm pretty sure it's regular heatshrink, although I have a couple of pieces of the double-wall stuff laying around. > Do you still have the terminal that broke off? > I'd like to have it if you could see fit to > mail it to me. Bob, Yes, I do still have it. My e-mail is johngoodmanATearthlink.net Send an address, and I'll mail it. The fatigue point is very close to the terminal. John -------- #40572 Phase One complete and flying. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=398187#398187 ________________________________ Message 8 _____________________________________ Time: 06:34:19 PM PST US From: "Chris" Subject: RE: AeroElectric-List: Butt Splice for #4 wire John, Did I miss it - I am sorry, but can you explain how you discovered the problem? Was it complete disconnect? Was the break on the alternator end or firewall end? Thanks Chris Lucas N919AR 40072 -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of johngoodman Sent: Sunday, April 07, 2013 10:41 AM Subject: AeroElectric-List: Butt Splice for #4 wire --> I have a #4 wire I need to put a new ring terminal on. It will make a tight reach. I think it will work, but I considered a #4 butt splice - they make 'em. If my new ring terminal makes it too short, my choice is adding a few inches of new #4 with a butt splice, or replacing the entire 5 foot length (which won't be easy to do). Opinions, please John -------- #40572 Phase One complete and flying. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=398043#398043 ________________________________ Message 9 _____________________________________ Time: 07:46:51 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Charging System Debug steps and success... At 12:04 PM 4/8/2013, you wrote: Greetings All, From time-to-time people have posted assorted problems, and gotten answers to, charging system issues. Many of these are of the wandering or oscillating voltage nature. Yes. The "galloping ammeter" syndrome is almost exclusive to alternator/regulator systems wherein the wire with duties to sense bus voltage ALSO carries alternator field current. This is a VERY common configuration in tens of millions of cars and tens of thousands of airplanes. A typical at-risk system uses the legacy FORD regulator featured in many of my writings and schematics. As my charging system (LongEz, externally regulator "ford-style" charging with regulator and battery in the nose) developed an oscillating attitude I had the "opportunity" to collect, review and then apply the information Bob has generously provided and thought an overview might prove useful for the next guy down the road. I'll start with key summary points for those who don't have the current need or desire to read through the details. My symptoms were an oscillating (2 - 6 Hz maybe?) charging voltage visible with the old (WesTach) panel meter. It was sufficient to pop the over-voltage crowbar once. It might also be related to an transient undervoltage alarm I got once. After isolating the problem, I fixed it by replacing the store-bought regulator connector (which had pig-tails, the bad connection was on the factory-made regulator +V crimp) with good-quality Fast-ons direct to the regulator. This dropped the alternator B+ to regulator V+ resistance from 528mOhms to ~140mOhms which fixed the problem. btw: the 140 ohms, which is still higher than I would like, seems to be roughly evenly shared by the fuse-link, breaker and switch (and associated wiring). Of course the ideal supply loop resistance is zero ohms. However a Bode plot of the closed-loop response of the alternator-regulator-aircraft system usually shows that several hundred mOhms can be tolerated before control loop stability margin becomes risky. The details and references for "the next guy": The debug strategy was to start by checking the resistance (using techniques appropriate for milliohm measurments), without doing any disconnecting of the current loop path from alternator B+ to the regulator and then back from the regulator ground (i.e. case) to the alternator ground (i.e. case). My plan was to keep dividing the problem in half to minimize debug time (i.e. binary search). I wanted to do as much testing as I could without taking anything apart as I didn't want to inadvertently change the problem (i.e. wiggle something and have the problem go away...) In the case that no problems were uncovered via the milliohm measurements, I then planned to follow Bob's charging component problem isolation technique which is in chapter 3 of the Aeroelectric connection book. This involves making measurements while the engine is running but I didn't need go to that step and I certainly didn't want to start there. For lots of charging system background and debug information, search Bob's site (www.aeroelectric.com) for "charging" and ignore all the stuff on plug-in-the-wall battery chargers. Bob has written articles and has product related to making good milliohm measurements using an applied current. I prefer having the current source (whether a bench supply or other similar to Bob's milliohm probes) separate rather than combining it with the volt-meter probes. Also, as Bob has covered in his articles, you don't need a regulated-to-a-known-value current source. It suffices to have an unregulated current source (like a D-cell, in a pinch) if you are using a second meter to measure the current. For more information on accurate milliohm measurements, search Bob's site for "milliohm". I conceptually divided the loop in half (ground side vs power side) and picked the ground side first. I put a current source (bench supply with an accurate current limit set to 1A (and set the voltage limit to be 2V though I didn't expect it to ever run in voltage mode regulation)) between the alternator case and the regulator case (which, on my LongEz is the length of the entire aircraft). I then measured the voltage (using separate wires) between the two cases and got 33.9mV which, at one amp, means 33.9mOhms. This is well below the ~200mOhms threshold area of concern (per Bob's annotations contained in "Know_Your_Charging_System.pdf"). Therefore the problem is in the V+ side. I repeated this on the V+ side which is a little bit trickier to measure as the "master" progressive switch needs to be in the "Alternator on" position which can add more currents to deal with (though, it turns out, not much). With the switch on, I measured the voltage from alternator B+ to regulator V+ both with the current source connected, and not connected. The value I care about is the connected value minus the not connected value. (though it still applies, I won't repeat this detail from now on). I measured 528mV (=528mOhms) which is well above the 200mOhm area of concern. So I've identified one (but maybe only the first?, it turned out to be only) problem. I then listed all (well, sort of, I didn't list both side of each wire...) of the connections between Alternator B+ and regulator V+. For me, starting from B+: Near side of load-meter shunt, near side of ANL, near side of fuse-link, near side of over-voltage breaker, nearside of alternator switch, V+ at the regulator. I kept the current source running between B+ on the alternator and regulator V+ (no reason to move it) and picked the point in the middle (near side ANL), B+ to near side ANL was only 11mV (=11mOhms). I continued the divide (roughly in half) and conquer approach (continuing to measure from B+ to my point of interest) which led me quickly to the crimp at the regulator. In the future I *might* start by measuring any connections I didn't personally make (of which there are very very few) before switching to the more disciplined binary search approach. In this case I would have gotten lucky but, in truth, it would not have saved much time. The time was spent going through Bob's articles and developing a plan. The execution of the plan went very fast. Repair and run-up test showed success. Specific Bob articles I found helpful (in addition to those on milliohm measurement): Know_Your_Charging_System.pdf 03_Alternator_12A2.pdf (i.e. the current chapter 3 in the aeroelectric connection, start at page 3-7 for debug info) Happy debugging! The phenomenon we're exploring is the twin brother of a 'ground loop'. In a ground loop, a potential noise current shares a conduction path with a potential victim (audio system, radio, etc). In our 'buss-loop', a noisy current (field supply) shares a pathway with a potential victim (voltage regulator). Operating currents for the alternator field can be anywhere between a few hundred milliamps (very light load, high rpm) to 3 or 4 amps (low rpm, high, load). The number and kind of accessories turned on at the time have a second order effect on control loop stability. If you have 500 milliohms of field supply resistance feeding a moderately loaded alternator current of say 2 amps, then the 2 amp x 0.5 ohms or 1 volt 'modulation' of voltage at the regulator's A/S terminals presents as a 1 volt error in the desired regulation set point. This is not a guarantee for unstable operation but the risks are very high. Wire resistance in the rest of the system has very low to zero risk for setting up the same condition. This problem came to light early on for single engine Cessnas. I addition to conductors that ran from bus to regulator, there were ohmic joints, (crimped pins, engaged pins, fast-ons, switch saddles, switch contacts, etc). I forget the exact number but I think I recall something like 19 ohmic joints in the Cessnas, far more than any other TC aircraft. About once a year I get an email from a TC Cessna owner asking about fixes for the 'galloping ammeter". Quite often, replacing one item in the constellation of system components provides relief . . . but it is temporary. My advice is to start at the bus and replace EVERYTHING with ohmic joints starting with breaker, master switch and it's fast-on terminals, and crimped on pins in all the Mate-n-Lok connectors. This 'shotgun' approach will reduce total path resistance to a value close to factory original values. Assuming the modern regulators have similar stability models, this approach should set the system up for another 40 years of stable operation. Steve, thank you so much for the validation of the simple-ideas offered as to root cause and remedy for this unique phenomenon. Good work my friend! 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.