---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 06/28/17: 16 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:04 AM - Re: Master contactor catch diode failure (Robert L. Nuckolls, III) 2. 04:05 AM - Re: Re: IVO Prop current limiter (Robert L. Nuckolls, III) 3. 04:39 AM - Re: Noisy radio system (user9253) 4. 04:59 AM - Re: IVO Prop current limiter (merlewagner2) 5. 07:21 AM - Re: Master contactor catch diode failure (William Hunter) 6. 12:40 PM - Re: Master contactor catch diode failure (Robert L. Nuckolls, III) 7. 12:47 PM - Re: Re: Master contactor catch diode failure (Robert L. Nuckolls, III) 8. 12:50 PM - Re: Master contactor catch diode failure (William Hunter) 9. 01:00 PM - Re: IVO Prop current limiter (kfav8r) 10. 01:11 PM - Re: Master contactor catch diode failure (Robert L. Nuckolls, III) 11. 01:24 PM - Re: Re: IVO Prop current limiter (Robert L. Nuckolls, III) 12. 01:49 PM - Re: Master contactor catch diode failure (William Hunter) 13. 02:56 PM - Re: Master contactor catch diode failure (Charlie England) 14. 05:33 PM - Re: Master contactor catch diode failure (user9253) 15. 06:33 PM - Re: Re: Master contactor catch diode failure (William Hunter) 16. 07:44 PM - Re: Re: Master contactor catch diode failure (don van santen) ________________________________ Message 1 _____________________________________ Time: 04:04:03 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Master contactor catch diode failure At 02:52 PM 6/27/2017, you wrote: >The most obvious answer is that the original diode was installed >backwards. Maybe the supplied "packaged" assembly from Vans was >incorrectly assembled under the heat shrink causing full battery >voltage and hence current to forward bias the diode leading to its >action as a fuse. The new assemblies shown in your photos leave no >possible clue as to the direction the encapsulated diode is >oriented. The external red band is fine and dandy, but if the diode >under the shrink was accidentally reversed there is no way to know >without "testing". I would suggest your "test" proved conclusively >it was incorrect. Agreed . . . with one other possibility . . . I have encountered plastic diodes that were incorrectly marked. Band on the wrong end. It's rare but I think I've seen it a couple of times. Further, they were a one-of event, not a 'batch' problem. I'm not sure this is possible but it's certainly low probability given modern manufacturing and grading techniques for diodes. But these days, there are diodes and then there are DIODES. Without knowing the critter's pedigree, we'll never know. In any case, replacing the diode is the permanent fix. Bob . . . ________________________________ Message 2 _____________________________________ Time: 04:05:47 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: IVO Prop current limiter At 01:37 PM 6/27/2017, you wrote: > >With Bob's prompting to move on to Plan B, I put together an >Arduino-based IVOProp "controller." > >I bought an Arduino clone, a relay module, and a current sensing >module, and wrote a program to monitor the prop current. When the >current goes above 9 Amps for a sufficiently long time, the program >opens the relay and shuts off the current. The red and green LEDS >are triggered to indicate the current flowing and not flowing to the >prop. The program leaves the relay open and the red LED on for a >few seconds so the pilot gets the message that a limit was reached. > >I just ran the engine and put the prop through its paces, and the >system seems to work well. There might be additional tweaking to >the code needed, but I think it's pretty close to good. GOOD for YOU! >I'll be happy to share the code and links to the components if >anyone is interested. Yes, I'd be interested in seeing your work. Bob . . . ________________________________ Message 3 _____________________________________ Time: 04:39:40 AM PST US Subject: AeroElectric-List: Re: Noisy radio system From: "user9253" Someone may correct me if wrong, but adding resistance to a circuit decreases the current. Therefore adding resistance will decrease the load on magnetos. An external antenna is a good idea. The ground plane does not necessarily have to be sheet metal. A ground plane can be made using 6 or 8 radials of copper tape or wire that are glued to the fabric. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=470545#470545 ________________________________ Message 4 _____________________________________ Time: 04:59:10 AM PST US Subject: AeroElectric-List: Re: IVO Prop current limiter From: "merlewagner2" I would also like to take a look at your setup. I am planning on using an IVO mag prop with in flight adj. Was hoping to do just what you have already done. Way ahead of me!!!! Merle > I'll be happy to share the code and links to the components if anyone is interested. hmmm, seems I screwed up the quoting somehow.. -------- KC1DNJ General Radiotelephone Commercial SEL A&P Building scale P51 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=470546#470546 ________________________________ Message 5 _____________________________________ Time: 07:21:06 AM PST US From: William Hunter Subject: Re: AeroElectric-List: Master contactor catch diode failure How does one (me) check a diode when it is installed on the contactor? I assume that you want to have the master switch off and use DC resistance. Does it matter what polarity to connect the leads? Thanks, Bill Hunter At 02:52 PM 6/27/2017, you wrote: The most obvious answer is that the original diode was installed backwards. Maybe the supplied "packaged" assembly from Vans was incorrectly assembled under the heat shrink causing full battery voltage and hence current to forward bias the diode leading to its action as a fuse. The new assemblies shown in your photos leave no possible clue as to the direction the encapsulated diode is oriented. The external red band is fine and dandy, but if the diode under the shrink was accidentally reversed there is no way to know without "testing". I would suggest your "test" proved conclusively it was incorrect. Agreed . . . with one other possibility . . . I have encountered plastic diodes that were incorrectly marked. Band on the wrong end. It's rare but I think I've seen it a couple of times. Further, they were a one-of event, not a 'batch' problem. I'm not sure this is possible but it's certainly low probability given modern manufacturing and grading techniques for diodes. But these days, there are diodes and then there are DIODES. Without knowing the critter's pedigree, we'll never know. In any case, replacing the diode is the permanent fix. Bob . . . ________________________________ Message 6 _____________________________________ Time: 12:40:20 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Master contactor catch diode failure At 09:20 AM 6/28/2017, you wrote: >How does one (me) check a diode when it is installed on the contactor? Just unhook one end (the small terminal) and use your ohmmeter function to test continuity through the diode. One configuration will show SOME value of resistance, reversing the leads will show infinite resistance. >I assume that you want to have the master switch off and use DC >resistance. Does it matter what polarity to connect the leads? You test BOTH ways . . . looking for basically NO conduction one way (off scale high resistance) and some value of resistance the other way . . . the exact value unimportant as it will vary from one ohmmeter to another. Bob . . . ________________________________ Message 7 _____________________________________ Time: 12:47:12 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Master contactor catch diode failure At 04:16 PM 6/27/2017, you wrote: > > >Bob McC wrote: > > The most obvious answer is that the original diode was installed backwards. > >That was my initial thought too but the aircraft had 29 hours TTSN >with that configuration. > >The RV-9A owner told me this incident happened on the first master >switch actuation after battery replacement due to a totally >discharged battery. THIS IS NOT GOOD . . . If the diode WAS good and fried after battery replacement, then the battery was hooked up BACKWARDS . . . This fries the catch diode and potentially, lots of other stuff. Years ago, I used to recommend adding a fuse in series with the battery master contactor wire that runs off to the master switch. When paired with a catch diode on the contactor the diode shorts out reversed voltage to the contactor preventing closure while the fuse blows preventing wire damage . . . and perhaps damage to the diode as well. But it sounds like this event went on long enough to open the diode, close the contactor and to put battery energy onto the ship's bus . . . Bob . . . ________________________________ Message 8 _____________________________________ Time: 12:50:44 PM PST US From: William Hunter Subject: Re: AeroElectric-List: Master contactor catch diode failure Thanks, Also, how warm do contactors get when they are energized? I have two contactors mounted in a well underneath the backseat of my airplane. This well is about three inches deep 20 inches wide and 12 inches long and it's completely sealed with no cooling air and since it is constructed of foam core fiberglass It is Well insulated and therefore none of the heat can get conducted out of the airplane. I felt them and the contactors do get warm but the question is how warm can they get and do they need any cooling air? Inflight only one contactor will be energized however on the ground during maintenance I will have both contactors energized. THANKS AGAIN FOR YOUR HELP Bill Hunter On Jun 28, 2017 12:44 PM, "Robert L. Nuckolls, III" < nuckolls.bob@aeroelectric.com> wrote: > At 09:20 AM 6/28/2017, you wrote: > > How does one (me) check a diode when it is installed on the contactor? > > > Just unhook one end (the small terminal) and use > your ohmmeter function to test continuity through > the diode. One configuration will show SOME value > of resistance, reversing the leads will show > infinite resistance. > > > I assume that you want to have the master switch off and use DC > resistance. Does it matter what polarity to connect the leads? > > > You test BOTH ways . . . looking for basically > NO conduction one way (off scale high resistance) > and some value of resistance the other way . . . > the exact value unimportant as it will vary > from one ohmmeter to another. > > Bob . . . > ________________________________ Message 9 _____________________________________ Time: 01:00:27 PM PST US Subject: AeroElectric-List: Re: IVO Prop current limiter From: "kfav8r" I'll get the info posted next week. -------- Doug Read this topic online here: http://forums.matronics.com/viewtopic.php?p=470559#470559 ________________________________ Message 10 ____________________________________ Time: 01:11:46 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Master contactor catch diode failure At 02:50 PM 6/28/2017, you wrote: >Thanks, > >Also, how warm do contactors get when they are energized? Too hot to touch but not hot enough to 'sizzle spit' http://tinyurl.com/mpcgp3t http://tinyurl.com/k6bwdqo >I have two contactors mounted in a well >underneath the backseat of my airplane.=C2 This >well is about three inches deep 20 inches wide >and 12 inches long and it's completely sealed >with no cooling air and since it is constructed >of foam core fiberglass It is Well insulated and >therefore none of the heat can get conducted out of the airplane. > >I felt them and the contactors do get warm but >the question is how warm can they get and do >they need any cooling air? Inflight only one >contactor will be energized however on the >ground during maintenance I will have both contactors energized. > >THANKS AGAIN FOR YOUR HELP Materials used in construction of these devices is rated for operating at temperatures well in excess of 100C . . . but of course, hotter than you would want to touch. Bob . . . ________________________________ Message 11 ____________________________________ Time: 01:24:58 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: IVO Prop current limiter At 03:00 PM 6/28/2017, you wrote: > >I'll get the info posted next week. This might be another opportunity for an open source project. Once you've finely tuned the code, we can poke it into chips for mounting on a dedicated ecb . . . have you considered solid-state switching as opposed to relay? Bob . . . ________________________________ Message 12 ____________________________________ Time: 01:49:27 PM PST US From: William Hunter Subject: Re: AeroElectric-List: Master contactor catch diode failure Thanks Bob!!! The next time I have them humming for two hours at room temperature I will lick them to see if spit sizzles. Thanks again, Bill Hunter On Jun 28, 2017 1:15 PM, "Robert L. Nuckolls, III" < nuckolls.bob@aeroelectric.com> wrote: > At 02:50 PM 6/28/2017, you wrote: > > Thanks, > > Also, how warm do contactors get when they are energized? > > > Too hot to touch but not hot enough to 'sizzle spit' > > http://tinyurl.com/mpcgp3t > > http://tinyurl.com/k6bwdqo > > > I have two contactors mounted in a well underneath the backseat of my > airplane.=C3=82 This well is about three inches deep 20 inches wide and 12 > inches long and it's completely sealed with no cooling air and since it i s > constructed of foam core fiberglass It is Well insulated and therefore no ne > of the heat can get conducted out of the airplane. > > I felt them and the contactors do get warm but the question is how warm > can they get and do they need any cooling air? Inflight only one contacto r > will be energized however on the ground during maintenance I will have bo th > contactors energized. > > THANKS AGAIN FOR YOUR HELP > > > Materials used in construction of these devices > is rated for operating at temperatures well in > excess of 100C . . . but of course, hotter than > you would want to touch. > > > Bob . . . > ________________________________ Message 13 ____________________________________ Time: 02:56:29 PM PST US Subject: Re: AeroElectric-List: Master contactor catch diode failure From: Charlie England Do be aware that the temp it will get a *lot* hotter in your sealed up insulated box than it will sitting on your kitchen counter. I wouldn't do what you're talking about, because I wouldn't want to melt my aircraft in that area. Component life might be a secondary issue, in this case (pardon the pun). On 6/28/2017 3:48 PM, William Hunter wrote: > > Thanks Bob!!! > > The next time I have them humming for two hours at room temperature I > will lick them to see if spit sizzles. > > Thanks again, > > Bill Hunter > > On Jun 28, 2017 1:15 PM, "Robert L. Nuckolls, III" > > > wrote: > > At 02:50 PM 6/28/2017, you wrote: > >> Thanks, >> >> Also, how warm do contactors get when they are energized? > > Too hot to touch but not hot enough to 'sizzle spit' > > http://tinyurl.com/mpcgp3t > > http://tinyurl.com/k6bwdqo > > > >> I have two contactors mounted in a well underneath the backseat >> of my airplane. This well is about three inches deep 20 inches >> wide and 12 inches long and it's completely sealed with no >> cooling air and since it is constructed of foam core fiberglass >> It is Well insulated and therefore none of the heat can get >> conducted out of the airplane. >> >> I felt them and the contactors do get warm but the question is >> how warm can they get and do they need any cooling air? Inflight >> only one contactor will be energized however on the ground during >> maintenance I will have both contactors energized. >> >> THANKS AGAIN FOR YOUR HELP > > Materials used in construction of these devices > is rated for operating at temperatures well in > excess of 100C . . . but of course, hotter than > you would want to touch. > > > Bob . . . > --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 14 ____________________________________ Time: 05:33:06 PM PST US Subject: AeroElectric-List: Re: Master contactor catch diode failure From: "user9253" I agree with Charlie. The heat given off by a fire (caused by hot contactors) will be a whole lot hotter than the heat given off by contactors exposed to circulating air. What is the purpose of an insulated box? At what temperature will the diode start conducting in the reverse direction? Nobody knows how hot it will get inside of the box because it depends on several factors: size of box, how well it is sealed, insulating properties of the box, ambient air temperature, wattage of the contactor, length of time contactor is energized. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=470566#470566 ________________________________ Message 15 ____________________________________ Time: 06:33:04 PM PST US From: William Hunter Subject: Re: AeroElectric-List: Re: Master contactor catch diode failure I appreciate everyone's opinions and suggestions!!! The airplane is a Velocity (pusher) so it is constructed of fiberglass foam sandwich panels and I was trying to move as much of the heavy electrical cables aft closer to the engine so I placed these components under the rear bench seat. The rear seat "pedestal" (support structure) is a fiberglass box integral with the fuselage also constructed with fiberglass foam sandwich panels that equate to an "enclosed box". I thought that this was an "elegant solution" to utilize this empty space as an electrical equipment box however I didn't really think about the BTU output of these contactors. I guess I could cut some vent openings into the pedestal and that would introduce some cabin ambient air into the box (four feet away from the heater floor vents) however this would not be forced air ventilation but still much better than an enclosed, sealed, and very insulated box. Thanks, Bill Hunter On Jun 28, 2017 5:37 PM, "user9253" wrote: > > I agree with Charlie. The heat given off by a fire (caused by hot > contactors) will be a whole lot hotter than the heat given off by > contactors exposed to circulating air. What is the purpose of an insulated > box? > At what temperature will the diode start conducting in the reverse > direction? Nobody knows how hot it will get inside of the box because it > depends on several factors: size of box, how well it is sealed, insulating > properties of the box, ambient air temperature, wattage of the contactor, > length of time contactor is energized. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=470566#470566 > > ________________________________ Message 16 ____________________________________ Time: 07:44:02 PM PST US From: don van santen Subject: Re: AeroElectric-List: Re: Master contactor catch diode failure I would put the battery contactor as close to the battery as possible and the starter contactor on thd engine side of the firewall. This is how the RV 10 is done, battery in rear battery contactor inches away and starter contactor on the front of the firewall. I realize that your are building a pusher but this will work fine. This also keeps the heay generating contactors out in the open and seperated from each other. On Jun 28, 2017 18:37, "William Hunter" wrote: > I appreciate everyone's opinions and suggestions!!! > > The airplane is a Velocity (pusher) so it is constructed of fiberglass > foam sandwich panels and I was trying to move as much of the heavy > electrical cables aft closer to the engine so I placed these components > under the rear bench seat. The rear seat "pedestal" (support structure) is > a fiberglass box integral with the fuselage also constructed with > fiberglass foam sandwich panels that equate to an "enclosed box". > > I thought that this was an "elegant solution" to utilize this empty space > as an electrical equipment box however I didn't really think about the BTU > output of these contactors. > > I guess I could cut some vent openings into the pedestal and that would > introduce some cabin ambient air into the box (four feet away from the > heater floor vents) however this would not be forced air ventilation but > still much better than an enclosed, sealed, and very insulated box. > > Thanks, > > Bill Hunter > On Jun 28, 2017 5:37 PM, "user9253" wrote: > >> >> I agree with Charlie. The heat given off by a fire (caused by hot >> contactors) will be a whole lot hotter than the heat given off by >> contactors exposed to circulating air. What is the purpose of an insulated >> box? >> At what temperature will the diode start conducting in the reverse >> direction? Nobody knows how hot it will get inside of the box because it >> depends on several factors: size of box, how well it is sealed, insulating >> properties of the box, ambient air temperature, wattage of the contactor, >> length of time contactor is energized. >> >> -------- >> Joe Gores >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p=470566#470566 >> >> >> >> >> >> >> =================================== >> - >> Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/ >> Navigator?AeroElectric-List >> =================================== >> FORUMS - >> eferrer" target="_blank">http://forums.matronics.com >> =================================== >> WIKI - >> errer" target="_blank">http://wiki.matronics.com >> =================================== >> b Site - >> -Matt Dralle, List Admin. >> rel="noreferrer" target="_blank">http://www.matronics.com/contribution >> =================================== >> >> >> >> ------------------------------------------------------------------------------------- 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.