---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 12/11/17: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:42 AM - Re: stacking ring terminals or ? (user9253) 2. 08:04 AM - Debug plan for flaky NavCom operation? (Andy Elliott) 3. 08:22 AM - Re: Bose ANR Jacks and Grounding, Alternator AC Limits (Airdog77) 4. 08:49 AM - Re: How do I prevent starter engaged LED from failing? (Airdog77) 5. 09:01 AM - Re: Debug plan for flaky NavCom operation? (Robert L. Nuckolls, III) 6. 09:50 AM - Re: Re: stacking ring terminals or ? (Ken Ryan) 7. 11:10 AM - Re: Re: Bose ANR Jacks and Grounding, Alternator AC Limits (don van santen) 8. 01:56 PM - diode vs snapjack (Ken Ryan) 9. 04:17 PM - Re: stacking ring terminals or ? (user9253) 10. 04:29 PM - Re: diode vs snapjack (user9253) 11. 04:56 PM - Re: Re: stacking ring terminals or ? (Ken Ryan) ________________________________ Message 1 _____________________________________ Time: 07:42:19 AM PST US Subject: AeroElectric-List: Re: stacking ring terminals or ? From: "user9253" A 5 amp circuit breaker should be big enough for the 35 amp alternator field. Capacitor current is not very much once energized. 18 AWG wire is big enough if the wire only carries capacitor current. The 10 amp fuse that activates the regulator also carries fuel pump #1 current and capacitor inrush current. Another consideration is if the rectifier/regulator output voltage happens to be higher than main alternator voltage, then the dynamo will power the whole aircraft while the momentary switch is closed. The momentary switch might only be closed for a couple of seconds, but that is all it takes to blow a fuse. It is only a matter of time before a pilot forgets to activate the rectifier/regulator. A diode could be used instead of a momentary switch. I used ExpressSCH to draw the circuit and Snagit to capture the picture. Or ExpressSCH can print to CutePDF Writer to make a PDF document. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476333#476333 Attachments: http://forums.matronics.com//files/diode_577.jpg ________________________________ Message 2 _____________________________________ Time: 08:04:30 AM PST US From: "Andy Elliott" Subject: AeroElectric-List: Debug plan for flaky NavCom operation? I have recently purchased an RV with an SL-30 as the #2 radio. Operation of this radio is very inconsistent. Typically on the ground on battery power I get good reception and transmission on local frequencies. Sometime after engine start, I pick up a *lot* of background static on some, but not all, frequencies. At least on the ground, I can still talk and receive on these frequencies, overcoming the static. But in the air, this radio is very flaky, both com and nav. Sometimes it seems to work OK, but sometimes I can't receive the local ATIS from 10 miles away when it is clear on the #1 radio. The static sometimes is there and sometimes not. Sometimes the VOR reception is good and correct, and sometimes it loses lock or report an obviously wrong radial. (I haven't tried the ILS yet.) My first thought was that there must be a bad ground somewhere, but before going in with the flashlight and meter (which is not a trivial process, of course), and before considering pulling the radio and having it tested (Garmin's flat repair prices are $$$.), I thought I would try to get a debug plan from the group here. Basically, I need a sequence of things to check in order, hopefully going from simple to more difficult, which would lead to (a) resolution of the problem or (b) a decision to send the radio for check/repair. Anyone have such a plan?? Thanks, Andy Elliott -------------------------- Andy Elliott, RV-8, N303RV CL: 480-695-9568 ________________________________ Message 3 _____________________________________ Time: 08:22:55 AM PST US Subject: AeroElectric-List: Re: Bose ANR Jacks and Grounding, Alternator AC Limits From: "Airdog77" Hi Don, I have mine wired up like Jared's, still in build mode so can't test yet. But just to clarify your statement: > I just finished a new install of two Lemo plugs and this time I cut the black/white wires off Meaning you cut them off totally? No other action with these 2 black/white wires? > spliced the shields from the head phone and mic cables to the audio panel shield wires. Essentially per a traditional headset jack install? Curious about this since my LEMO plug sits adjacent to the standard plugs. I wired per Bose instructions. My black/white wires connect to the white/blue wire (low) tab of the jacks. Since the black/white wires are simply a wire extension of each cable pair (phone & mic/ptt) ground shield, is it fair to say in sticking with the LEMO+standard jacks configuration that IF I hear noise I should disconnect the black/white wires from each jack tab and subsequently wire each black/white wire into the respective standard jack's cable shields? To be clear, my headset jack wire shields currently simply terminate (no connection) at the jack end and are just "floating." Cheers, Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476335#476335 ________________________________ Message 4 _____________________________________ Time: 08:49:52 AM PST US Subject: AeroElectric-List: Re: How do I prevent starter engaged LED from failing? From: "Airdog77" Bob, I'm getting to ready to build my engine the middle of next month (Jan 18 ) and wanted to clarify the starter-on warning circuit. I have mine depicted as per the Z-13/8 diagram with a connected wire off the starter contactor post. Off the starter contactor, the lead then runs through a 2A inline fuse, then a 2K ohm resistor (as per AG6 instructions) and then runs back to the panel (I'm in a Long-EZ, so up to the front) and terminates into an AG6 warning annunciator as my "warning light." First, in this configuration would there be any reason to change the starter-on warning wire lead connection point from the contactor post to the actual starter? Second, I'm thinking for the protection of the AG6 I should add a protective diode hanging off the circuit either as you and/or Joe depicted. Do you think this is advisable for my configuration? Thanks, Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476336#476336 ________________________________ Message 5 _____________________________________ Time: 09:01:09 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Debug plan for flaky NavCom operation? > >But in the air, this radio is very flaky, both com and >nav. Sometimes it seems to work OK, but sometimes I can't receive >the local ATIS from 10 miles away when it is clear on the #1 >radio. The static sometimes is there and sometimes not. Sometimes >the VOR reception is good and correct, and sometimes it loses lock >or report an obviously wrong radial. (I haven't tried the ILS yet.) > >My first thought was that there must be a bad ground somewhere, but >before going in with the flashlight and meter (which is not a >trivial process, of course), and before considering pulling the >radio and having it tested (Garmin's flat repair prices are $$$.), I >thought I would try to get a debug plan from the group >here. Basically, I need a sequence of things to check in order, >hopefully going from simple to more difficult, which would lead to >(a) resolution of the problem or (b) a decision to send the radio >for check/repair. If I'm reading the installation manual correctly, the nav and comm sections of this radio are completely independently powered with their own antennas and audio outputs. The fact that both features are affected suggests that the problem is not in the radio itself. Is your avionics shop local or do you have to ship the radio off? I used to be able to get a functional look-see done on a radio for a very nominal price . . . not looking for an inspection for return to service, just sensitivity chex on one frequency of each radio and normal transmitter behavior. This is a simple if not cheap check that would rule in/out installation deficiencies. Do you have an audio panel? Has the SL30 radio ever worked for you or has it always been flaky? Are you using a splitter on the nav antenna to drive both #1 and SL30? You might try swapping the comm antennas between the two radios and doing a VSWR check on both antennas while you're at it. Is the problem consistent whether or not the engine is running? Whether or not the alternator is on line? Bob . . . ________________________________ Message 6 _____________________________________ Time: 09:50:40 AM PST US From: Ken Ryan Subject: Re: AeroElectric-List: Re: stacking ring terminals or ? Thanks as always Joe. Comments: The 10 amp fuse that activates the regulator also carries fuel pump #1 current and capacitor inrush current. I had not considered this, but with #16 wire I should be able up the fuse size if necessary. Another consideration is if the rectifier/regulator output voltage happens to be higher than main alternator voltage, then the dynamo will power the whole aircraft while the momentary switch is closed. The momentary switch might only be closed for a couple of seconds, but that is all it takes to blow a fuse. I had not considered this, either. Rotax says the reg/rect output is 14 +/- 0.3 volts from 1000 +/- 250 rpm and the alternator output is 14.2 - 14.8 volts. Additionally I finally found a source for the Silent-Hektik regulator, which I have ordered and will probably use. The Silent-Hektik has a stepped charging profile whereby it starts out at only 12.5 volts for the first three minutes, peaking at about 14.4 volts. So, I'm not sure whether or not the dynamo will be carrying the bus while the momentary contact switch is closed. Let's consider what happens during operation. Startup procedure is to turn on the auxiliary pump and crank the engine. The oil pressure switch allows the auxiliary pump to instantly energize and get the engine running. Now the engine is running and the alternator is presumed to be supplying the bus with 14.2 - 14.8 volts. The next step is to energize the regulator-rectifier using the momentary contact switch. This will energize the primary fuel pump and also energize (as you have pointed out) the wire from the capacitor, through the switch and 10 amp fuse, to the bus. If the alternator voltage is less than the reg/rect voltage, that wire will also be carrying all bus loads for the time that the momentary switch is closed. This could blow the 10 amp fuse. Even if I increase that fuse to 15 amps, it is possible it could blow. Keep in mind that this is all happening on the ground, so if the fuse blows it is not a disaster. Given that this circuit is #16 wire, and that the switch is momentary (couple of seconds at most) do you think it would be okay to use a 20 amp fuse for this circuit? If yes, I think that solves that problem. This brings up another question I have. When that same switch (ON)-OFF-ON is placed in the ON position, that wire is again connected to the bus. But at the same time the relay is closed and the fatter #12 wire is also connected to the bus. I am assuming that the two wires will share the loads and the fuse size on the #16 wire will no longer be an issue. Is that correct? Another possible scenario would be flying along normally, with the alternator carrying the bus and the dynamo carrying the main fuel pump. Suppose the momentary contact switch is inadvertantly closed under this scenario, and the fuse in question does blow. What would happen? It seems to me that main fuel pump should continue to run, and the alternator should continue to supply the bus. The only thing lost would be the ability to energize the reg/rect using bus voltage (after the engine is shut down). Do you agree? It is only a matter of time before a pilot forgets to activate the rectifier/regulator. A diode could be used instead of a momentary switch. It could happen, but given that it is tied to fuel pump management on an engine that requires an electric fuel pump to run, that would be some very sloppy piloting. It is very much like saying "it is only a matter of time before the pilot forgets to put fuel in the airplane." But let's look at the diode possibility anyway. If a diode were used instead of the switch as shown in your drawing, then on startup the reg/rect would be energized as soon as the dynamo spits out enough voltage to activate it. Only then would the main fuel pump become energized. It might be necessary to turn on the auxiliary pump for starting. If it is, that means that on startup both fuel pumps would be running. I don't see any problem with that. But what about the need to disconnect the reg/rect to prevent running down the battery? I guess that is covered by the battery contactor. Or maybe the diode itself protects against this? So it appears that the diode instead of the switch should work for energizing the reg/rect. Would a diode also address the previously discussed possibility of blowing the fuse because the #16 wire might be carrying the bus loads (rather than the alternator)? It seems that it would. Are there any downsides? Is a diode more or less prone to failure than a switch? (It seems that diode failure in alternators is pretty common.) What are the failure modes of a diode? Does it make any difference where in the wire the diode is located? You always make me think, Joe. Ken On Mon, Dec 11, 2017 at 6:41 AM, user9253 wrote: > > A 5 amp circuit breaker should be big enough for the 35 > amp alternator field. > Capacitor current is not very much once energized. > 18 AWG wire is big enough if the wire only carries > capacitor current. > The 10 amp fuse that activates the regulator also > carries fuel pump #1 current and capacitor inrush > current. Another consideration is if the > rectifier/regulator output voltage happens to be higher > than main alternator voltage, then the dynamo will power > the whole aircraft while the momentary switch is closed. > The momentary switch might only be closed for a couple > of seconds, but that is all it takes to blow a fuse. > It is only a matter of time before a pilot forgets to activate > the rectifier/regulator. A diode could be used instead of a > momentary switch. > I used ExpressSCH to draw the circuit and Snagit to capture > the picture. Or ExpressSCH can print to CutePDF Writer to > make a PDF document. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=476333#476333 > > > Attachments: > > http://forums.matronics.com//files/diode_577.jpg > > ________________________________ Message 7 _____________________________________ Time: 11:10:50 AM PST US From: don van santen Subject: Re: AeroElectric-List: Re: Bose ANR Jacks and Grounding, Alternator AC Limits The B/w wires are connected to the mic and headphone shields at the Lemo plug end.The shields are floating at the Lemo plug end The B/W wire is supposed to connect to the existing shieldsfor the mic and phones. In my case this would have left 3 feet of shield ground wire and the normal is to keep this wire leng to under 3 inches.I did this by cutting the B/W wire off at the lemo end. I left the shield floating at the Lemo end and joined the shields where I spliced into the corespnoding wires from the audio panel.The fully shielded conductors then had the shields terminated at the audio panel.I believe that using three feet of shield ground wire was the entry point of my noise issue. The problem was eliminated but I can not prove that my fix was the solution. On Monday, December 11, 2017, Airdog77 wrote: > > Hi Don, > > I have mine wired up like Jared's, still in build mode so can't test yet. But just to clarify your statement: > > >> I just finished a new install of two Lemo plugs and this time I cut the black/white wires off > > > Meaning you cut them off totally? No other action with these 2 black/white wires? > > >> spliced the shields from the head phone and mic cables to the audio panel shield wires. > > > Essentially per a traditional headset jack install? > > Curious about this since my LEMO plug sits adjacent to the standard plugs. I wired per Bose instructions. My black/white wires connect to the white/blue wire (low) tab of the jacks. > > Since the black/white wires are simply a wire extension of each cable pair (phone & mic/ptt) ground shield, is it fair to say in sticking with the LEMO+standard jacks configuration that IF I hear noise I should disconnect the black/white wires from each jack tab and subsequently wire each black/white wire into the respective standard jack's cable shields? > > To be clear, my headset jack wire shields currently simply terminate (no connection) at the jack end and are just "floating." > > Cheers, > Wade > > -------- > Airdog > Wade Parton > Building Long-EZ N916WP > www.longezpush.com > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=476335#476335 > > ________________________________ Message 8 _____________________________________ Time: 01:56:41 PM PST US From: Ken Ryan Subject: AeroElectric-List: diode vs snapjack Which is better for use on relays, the "standard" diode or the "snapjack" (bi-directional zener transient voltage suppressor)? Ken ________________________________ Message 9 _____________________________________ Time: 04:17:36 PM PST US Subject: AeroElectric-List: Re: stacking ring terminals or ? From: "user9253" Ken, I see nothing wrong with the reasoning in your last post. But about the 10 amp fuse and momentary switch circuit, I suggest that the (ON)-OFF-ON switch be replaced with a simple ON-OFF SPST switch to energize the relay coil. Replace that 10 amp fuse with a 3 amp fuse. When you want to activate the reg/rect, just turn on the relay, then shut it back off. There is no worry about ampacity of wires or fuse. Now if you want to reduce pilot workload and make that function automatic, then use a fuse and diode between the starter and reg/rect, assuming that the starter contactor will remain energized until the reg/rect is operating. The diode will allow current to flow in only one direction, towards the reg/rect. A switch is more likely to fail than a diode if the diode is properly rated and installed. Diodes fail if they get too hot. Keep them cool and they will last a very long time. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476349#476349 ________________________________ Message 10 ____________________________________ Time: 04:29:41 PM PST US Subject: AeroElectric-List: Re: diode vs snapjack From: "user9253" Whichever is less expensive and easiest to install. A few years ago there was a "heated discussion" between two very knowledgeable people on this forum. I listened to both sides and do not think it matters. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=476350#476350 ________________________________ Message 11 ____________________________________ Time: 04:56:31 PM PST US From: Ken Ryan Subject: Re: AeroElectric-List: Re: stacking ring terminals or ? Thanks Joe, now I follow you. I like both approaches. I think I will go with using the relay to energize the reg/rect. To me it makes operations more intuitive. It's a definite improvement getting rid of that three way switch. It is not intuitive to have one switch that behaves differently from all the others. Thanks also for your comment on the snapjack vs diodes. I bought some snapjacks a while back, so I will use them. Ken On Mon, Dec 11, 2017 at 3:17 PM, user9253 wrote: > > Ken, I see nothing wrong with the reasoning in your last post. But > about the 10 amp fuse and momentary switch circuit, I suggest that > the (ON)-OFF-ON switch be replaced with a simple ON-OFF SPST switch > to energize the relay coil. Replace that 10 amp fuse with a 3 amp fuse. > When you want to activate the reg/rect, just turn on the relay, then shut > it back off. There is no worry about ampacity of wires or fuse. > Now if you want to reduce pilot workload and make that function > automatic, > then use a fuse and diode between the starter and reg/rect, assuming that > the starter contactor will remain energized until the reg/rect is > operating. > The diode will allow current to flow in only one direction, towards the > reg/rect. > A switch is more likely to fail than a diode if the diode is properly > rated > and installed. Diodes fail if they get too hot. Keep them cool and they > will last a very long time. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=476349#476349 > > ------------------------------------------------------------------------------------- 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.