---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 08/19/14: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:43 AM - Re: Dynon D-180 & flickering LEDs (Robert L. Nuckolls, III) 2. 07:54 AM - PM alternator capacitors . . . (Robert L. Nuckolls, III) 3. 12:18 PM - Re: Z-19 Function (Robert L. Nuckolls, III) 4. 12:25 PM - Re: Real life lessons in wire ratings . . . (Jay Hyde) 5. 12:28 PM - Re: Real life lessons in wire ratings . . . (Jay Hyde) 6. 12:59 PM - Re: Real life lessons in wire ratings . . . (rayj) 7. 02:22 PM - Re: Z-19 Function (Justin Jones) 8. 05:13 PM - Re: Z-19 Function (Robert L. Nuckolls, III) 9. 05:22 PM - Re: Real life lessons in wire ratings . . . (Robert L. Nuckolls, III) 10. 05:30 PM - Re: Z-19 Function (Justin Jones) ________________________________ Message 1 _____________________________________ Time: 05:43:38 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Dynon D-180 & flickering LEDs At 09:51 PM 8/18/2014, you wrote: I have been corresponding with a RV-12 owner in TX. His Dynon D-180 has a problem with LEDs that flicker when they should be on steady. The D-180 supplies negative PWM voltage to LEDs which are external to the D-180. Download the D-180 Installation Manual http://www.dynonavionics.com/downloads/Install_Guides/FlightDEK-D180_Installation_Guide_Rev_H.pdf and read about "External EMS Warning Light" on page 4-10. The aircraft owner did some experiments. Here are the results: With the engine off and the D-180 powered by the aircraft battery, the LEDs are on steady. With the engine running, the LEDs flicker. With the engine still running, if the avionics switch is shut off, the D-180 reverts to its internal backup battery and the LEDs illuminate steadily. Engine still running and the avionics switch is turned back on, the LEDs flicker again. This experiment was repeated and the results are consistent. From these experiments I conclude that the D-180 puts out a steady PWM voltage when operating on battery power (whether aircraft battery or internal backup battery). And when operating off the alternator, the D-180 puts out an intermittent PWM voltage which causes LED flicker. Do I presume correctly that he has gone through the set up screen for managing the output of this pin? To configure EMS DB37 Pin 29 as an external warning light, enter the EMS menu by pressing any button beneath an EMS main page. Press MORE > SETUP > GLOBAL. Press DOWN. to select ALARM CONFIG and press SEL. LGT BHVR: ACK SOLID configures the external alarm light to remain on (solid) when the alarm condition is acknowledged. LGT BHVR: ACK CLEAR configures the external alarm light to go off when the alarm condition is acknowledged. The word 'flicker' implies a visible, random modulation of the light output. If this output is being deliberately PWM for the purpose of controlling apparent intensity, the PWM frequency will be too high for the eye to perceive anything like a 'flicker' . . . it seems unlikely that the difficulty is a function of any normal behaviors designed into the D-180. With the engine running, the D-180 indicates a system voltage of 13.7 which is normal for RV-12s. All E-LSA RV-12s have a 22,000 microfarad capacitor connected to the output of the Rotax rectifier/regualtor. If that capacitor is bad, could that cause the D-180 to output an unsteady PWM voltage to the the LEDs? Or should the D-180 be able to function even if the aircraft electrical power is dirty and not pure DC? If you put a 'scope on the bus of any airplane with the alternator running you will find that it's anything but "pure DC". Mil-Std-704/DO-160 design and qualification recommendations advise system integrators to consider this in the design of bus-powered products. Dynon is no less aware of this than anyone else . . . and based on my conversations with them, perhaps more so. The legacy 22,000 uF capacitor installation on PM alternators is of limited utility for smoothing the output from PM alternator rectifier/regulators. Peek at the bus with a 'scope and do a capacitor-connected/disconnected comparison for confirmation. A casual observation with a 'scope will not produce much confidence that the capacitor is doing anything useful in the time domain. See: http://tinyurl.com/n5yd3vw Some day I may get the chance to put a spectrum analyzer on the bus and get some details for benefits in the frequency domain . . . but I don't expect to see anything that would alter the way we do system integration under 704/160 design goals. I suggest that he experiment with an incandescent lamp wired to this output and powered from a couple of lantern batteries or line operated bench supply. Then hook the lamp to the bus for power to see if behavior changes. He could also consider talking to the folks who designed and built the system. They're very amiable folks (at least they were the last time I talked with them perhaps 4 years ago). They're going to know more about their system than anyone you're going to find on this List . . . or in-the-wild. Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:54:35 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: PM alternator capacitors . . . The legacy 22,000 uF capacitor installation on PM alternators is of limited utility for smoothing the output from PM alternator rectifier/regulators. Peek at the bus with a 'scope and do a capacitor-connected/disconnected comparison for confirmation. A casual observation with a 'scope will not produce much confidence that the capacitor is doing anything useful in the time domain. See: http://tinyurl.com/n5yd3vw ======================= I was asked about the significance of the data cited above . . . and I beg your indulgence . . . it's not immediately obvious. I've re-posted the data package and encircled the pertinent data points: RMS and peak-to-peak voltage numbers cited at the edge of the 'scope screen. These Pk-Pk values speak to the greatest voltage excursions detected in the displayed plot . . . you can have some pretty high numbers here if the wave form shows even the shortest of 'spikes' . . . pk-to-pk numbers are not terribly significant in these plots. RMS speaks to the ENERGY in the noise. Note that for ALL conditions measured, there are no gross variations in measured noise configurations of capacitor size and whether or not a battery is on line. All measured values were well under those we are told to expect on the legacy 704/160 realm of DC power systems. Publication of this data is not intended to say that there is no value for including a capacitor . . . but the published narratives don't speak to any rationale other than noise mitigation. It may be that some clever designer perceived an improvement in performance for something other than noise. If so, I'm unaware of it. Bob . . . ________________________________ Message 3 _____________________________________ Time: 12:18:43 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-19 Function At 12:36 PM 8/18/2014, you wrote: >Bob, > >I appreciate your help and opinion with this matter. I will >approach Robert about this and find out the specifics of the >electrical demands of his system. I have heard great things about >his customer service and the folks using his system in their running >aircraft have nothing but great things to say about it and him. He >is a very knowledgable A&P and has deep knowledge of his system. > >Thank you again. > >Justin Is there a real wiring diagram for this system? The manual speaks to the need for 4 breakers in a dual ECU system but I find only references to ECU power connections in the harness picture. Do I have all the documentation for this system? Bob . . . ________________________________ Message 4 _____________________________________ Time: 12:25:01 PM PST US From: "Jay Hyde" Subject: RE: AeroElectric-List: Real life lessons in wire ratings . . . And don't even think of operating a welding machine on a coiled up extension line.. J Different story: Volt drop when pulling high current seriously deteriorates performance; on a construction site that I was working on our sub contracting welding team strung out 100+m (around 300') of 2.5mm2 cable (roughly 13 AWG) and tried to weld (using a single phase hand carried machine) on that. They kept tripping the supply transformer and annoying everyone connected to it- through a number of faults that the protection devices were observing; exactly what I don't know as I was busy with something else and couldn't investigate, but from the timing clearly they were the ones doing it. 'For some reason' they couldn't get the weld quality they needed, and the power kept tripping. J >From what I could reason the huge volt drop across the cable, created by the long length and the small cross sectional area (and hence greater impedance) caused the welder to draw more current; cable heats up, creating more resistance, more volt drop, more current draw- more current; cable heats up, creating more resistance, more volt drop, more current draw and so it goes on. Long wires require careful attention.. Johannesburg Jay From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: 19 August 2014 04:43 AM Subject: AeroElectric-List: Real life lessons in wire ratings . . . Last weekend, Dr. Dee and I spent Friday/Saturday supporting our son's shaved ice and cotton candy business during "Old Settlers Days" in Mulvane, KS. Temperature in upper 90s. Shaved ice trailer with lights, rooftop a/c, freezer and shaved ice machine running on ac mains through 100', 12AWG extension cord not unlike that pictured below. Total current draw on the order of 13 amps. Emacs! Approximately 70' of cord was spooled out leaving about 30' still coiled on the reel. After 3 or 4 hours operation, a vendor on the row behind us asked if that 'smoke and bad smell' was something to be concerned about. I swapped out the smoking cord for a spare. I un-spooled the rest of the cord and discovered that when not allowed the benefits of cooling air, the wrapped up coils got pretty hot. The cord that was spooled out was warmer than ambient but not markedly so. Voltage at plug end under load was 124 volts . . . inside trailer it was 117 volts for a round trip drop of about 7 volts. Nonetheless, insulation on the poorly cooled wires inside the yellow jacket fused together. In some places the yellow jacket was breached and/or fused to adjacent turns. This cord reel is designed to encourage rolling out only that cordage which is needed . . . but if you're going to load it to near max ratings, then it's a good idea to un-spool the entire length. A profound demonstration of how temp rise on a wire is exacerbated by constriction of free air cooling. I cut off the damaged 30', installed a new plug and left the full in-service length of cord laid out on the ground for the rest of the event. Voltage drop went down to just over 5 volts on the shortened cord. Bob . . . ________________________________ Message 5 _____________________________________ Time: 12:28:00 PM PST US From: "Jay Hyde" Subject: RE: AeroElectric-List: Real life lessons in wire ratings . . . And don't even think of operating a welding machine on a coiled up extension line.. J Different story: Volt drop when pulling high current seriously deteriorates performance; on a construction site that I was working on our sub contracting welding team strung out 100+m (around 300') of 2.5mm2 cable (roughly 13 AWG) and tried to weld (using a single phase hand carried machine) on that. They kept tripping the supply transformer and annoying everyone connected to it- through a number of faults that the protection devices were observing; exactly what I don't know as I was busy with something else and couldn't investigate, but from the timing clearly they were the ones doing it. 'For some reason' they couldn't get the weld quality they needed, and the power kept tripping. J >From what I could reason the huge volt drop across the cable, created by the long length and the small cross sectional area (and hence greater impedance) caused the welder to draw more current; cable heats up, creating more resistance, more volt drop, more current draw- more current; cable heats up, creating more resistance, more volt drop, more current draw and so it goes on. Long wires require careful attention.. Johannesburg Jay From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: 19 August 2014 04:43 AM Subject: AeroElectric-List: Real life lessons in wire ratings . . . Last weekend, Dr. Dee and I spent Friday/Saturday supporting our son's shaved ice and cotton candy business during "Old Settlers Days" in Mulvane, KS. Temperature in upper 90s. Shaved ice trailer with lights, rooftop a/c, freezer and shaved ice machine running on ac mains through 100', 12AWG extension cord not unlike that pictured below. Total current draw on the order of 13 amps. Emacs! Approximately 70' of cord was spooled out leaving about 30' still coiled on the reel. After 3 or 4 hours operation, a vendor on the row behind us asked if that 'smoke and bad smell' was something to be concerned about. I swapped out the smoking cord for a spare. I un-spooled the rest of the cord and discovered that when not allowed the benefits of cooling air, the wrapped up coils got pretty hot. The cord that was spooled out was warmer than ambient but not markedly so. Voltage at plug end under load was 124 volts . . . inside trailer it was 117 volts for a round trip drop of about 7 volts. Nonetheless, insulation on the poorly cooled wires inside the yellow jacket fused together. In some places the yellow jacket was breached and/or fused to adjacent turns. This cord reel is designed to encourage rolling out only that cordage which is needed . . . but if you're going to load it to near max ratings, then it's a good idea to un-spool the entire length. A profound demonstration of how temp rise on a wire is exacerbated by constriction of free air cooling. I cut off the damaged 30', installed a new plug and left the full in-service length of cord laid out on the ground for the rest of the event. Voltage drop went down to just over 5 volts on the shortened cord. Bob . . . ________________________________ Message 6 _____________________________________ Time: 12:59:49 PM PST US From: rayj Subject: Re: AeroElectric-List: Real life lessons in wire ratings . . . Was the insulation on the individual conductors compromised? Was there any indication that there was the threat of an actual short occurring or was it just a matter of the outer jacket melting? Who was the manufacturer and/or what brand name was the cord sold under? Raymond Julian Kettle River, MN The things we admire in men, kindness and generosity, openness, honesty, understanding and feeling are the concomitants of failure in our system. And those traits we detest, sharpness, greed, acquisitiveness, meanness, egotism and self-interest are the traits of success. And while men admire the quality of the first they love the produce of the second. -John Steinbeck, novelist, Nobel laureate (1902-1968) On 08/18/2014 09:43 PM, Robert L. Nuckolls, III wrote: > Last weekend, Dr. Dee and I spent Friday/Saturday > supporting our son's shaved ice and cotton candy > business during "Old Settlers Days" in Mulvane, KS. > > Temperature in upper 90s. Shaved ice trailer with > lights, rooftop a/c, freezer and shaved ice machine > running on ac mains through 100', 12AWG extension > cord not unlike that pictured below. Total current > draw on the order of 13 amps. > > Emacs! > Approximately 70' of cord was spooled out leaving about > 30' still coiled on the reel. After 3 or 4 hours operation, > a vendor on the row behind us asked if that 'smoke and > bad smell' was something to be concerned about. > > I swapped out the smoking cord for a spare. > > I un-spooled the rest of the cord and discovered that > when not allowed the benefits of cooling air, the wrapped > up coils got pretty hot. The cord that was spooled out > was warmer than ambient but not markedly so. Voltage > at plug end under load was 124 volts . . . inside trailer > it was 117 volts for a round trip drop of about 7 volts. > > Nonetheless, insulation on the poorly cooled wires > inside the yellow jacket fused together. In some places > the yellow jacket was breached and/or fused to adjacent > turns. > > This cord reel is designed to encourage rolling out only > that cordage which is needed . . . but if you're going > to load it to near max ratings, then it's a good idea > to un-spool the entire length. > > A profound demonstration of how temp rise on > a wire is exacerbated by constriction of free air cooling. > I cut off the damaged 30', installed a new plug and > left the full in-service length of cord laid out on > the ground for the rest of the event. Voltage drop > went down to just over 5 volts on the shortened cord. > > Bob . . . > ________________________________ Message 7 _____________________________________ Time: 02:22:08 PM PST US From: Justin Jones Subject: Re: AeroElectric-List: Z-19 Function Bob, I just sent the request for the diagram to Robert. I will forward it along as soon as it comes in. Thanks Justin On Aug 19, 2014, at 11:16 AM, Robert L. Nuckolls, III wrote: > At 12:36 PM 8/18/2014, you wrote: >> Bob, >> >> I appreciate your help and opinion with this matter. I will approach Robert about this and find out the specifics of the electrical demands of his system. I have heard great things about his customer service and the folks using his system in their running aircraft have nothing but great things to say about it and him. He is a very knowledgable A&P and has deep knowledge of his system. >> >> Thank you again. >> >> Justin > > Is there a real wiring diagram for this system? The manual > speaks to the need for 4 breakers in a dual ECU system > but I find only references to ECU power connections in > the harness picture. Do I have all the documentation > for this system? > > > Bob . . . > > > > ________________________________ Message 8 _____________________________________ Time: 05:13:19 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Z-19 Function At 04:21 PM 8/19/2014, you wrote: >Bob, > >I just sent the request for the diagram to Robert. I will forward >it along as soon as it comes in. So I take it that you were expected to install this system with no wiring diagram? Bob . . . ________________________________ Message 9 _____________________________________ Time: 05:22:28 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Real life lessons in wire ratings . . . At 02:58 PM 8/19/2014, you wrote: > >Was the insulation on the individual conductors compromised? Was >there any indication that there was the threat of an actual short >occurring or was it just a matter of the outer jacket melting? No, all levels of insulation was being deformed. Temperatures were high enough to cause visible smoke. No short before it was unplugged. >Who was the manufacturer and/or what brand name was the cord sold under? It's not a NEMA graded cordage but no reason to believe it's not adequate to the ratings common to the wire (12AWG). The portions that were laying out on the ground were 'happy' . . . only those turns deprived of opan-air cooling got into trouble. Wire bundles in airplane will do the same thing. Emacs! Here's a piece of 22759, 10AWG in a bundle 'protected' by silicone impregnated fiberglas transiting a hot environment. Got hot enough for the Tefzel wrap to separate at edge bond. Bob . . . ________________________________ Message 10 ____________________________________ Time: 05:30:06 PM PST US Subject: Re: AeroElectric-List: Z-19 Function From: Justin Jones I have just the installation instructions at this time. Not sure if I have ever seen a wiring diagram for it. Justin On Aug 19, 2014, at 4:08 PM, Robert L. Nuckolls, III wrote: > > At 04:21 PM 8/19/2014, you wrote: >> Bob, >> >> I just sent the request for the diagram to Robert. I will forward it along as soon as it comes in. > > So I take it that you were expected to install this > system with no wiring diagram? > > > > 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.