---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 08/11/10: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:37 AM - Re: GROUND LOOPS (tomcostanza) 2. 08:59 AM - Re: Re: GROUND LOOPS (Robert L. Nuckolls, III) 3. 09:21 AM - Re: CdS Photocell Holder/Fixture (Robert L. Nuckolls, III) 4. 09:56 AM - Re: CdS Photocell Holder/Fixture (David E. Nelson) 5. 10:35 AM - Re: New Z-8 drawing (jonlaury) 6. 04:31 PM - Re: Re: New Z-8 drawing (Robert L. Nuckolls, III) 7. 11:21 PM - Re: New Z-8 drawing (jonlaury) ________________________________ Message 1 _____________________________________ Time: 03:37:23 AM PST US Subject: AeroElectric-List: Re: GROUND LOOPS From: "tomcostanza" Hey Bob, Could you explain, or point me to an explanation of, what kinds of things qualify as antagonists? From your reply to this question, it's clear I don't understand. -------- Clear Skies, Tom Costanza Read this topic online here: http://forums.matronics.com/viewtopic.php?p=308337#308337 ________________________________ Message 2 _____________________________________ Time: 08:59:01 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: GROUND LOOPS At 05:33 AM 8/11/2010, you wrote: > > >Hey Bob, > >Could you explain, or point me to an explanation of, what kinds of >things qualify as antagonists? From your reply to this question, >it's clear I don't understand. 99% of the time, antagonists are generally those devices which generate noise in the form of electrical "wiggles". These include radios that are poorly shielded. Motors. Strobe power supplies. Certainly alternators. Instruments with poorly shielded/filtered LCD power supplies. Switchmode power adapters common to many hand-held devices including GPS, cellphones, PDA, MP3 players, etc. There are some instances where non-wigglers like incandescent landing lights, pitot heaters, nav lights, etc can influence other systems . . . like the example I gave for poorly grounded engine instruments being affected by variations in current flowing through a crankcase-to-battery ground conductor. Even if the device IS a potential antagonist (like a strobe power supply), not carrying it's power ground back to a single point does not represent a risk as long as POTENTIAL victims do not share the same ground path. This is discussed in some detail in chapter 16 of the 'Connection. In that work I attempt to explain that potential victims and antagonists can and do coexist in airplanes as long as you make sure there is no PROPAGATION mode for the conveyance of malicious energy between them. Breaking of propagation pathways includes but is not limited to certain kinds of shielding, filters, modification of design to reduce noise and installation practices to eliminate shared ground paths. I can tell you that airplanes like the Beechjet have HUGE potential antagonists, and exceedingly vulnerable victims that for the most part have worked side by side for a long time. This is a design goal for every TC aircraft and should be a goal for OBAM aircraft as well. The vast majority of your potential victims reside on the panel. Judicious attention to grounding at the panel will greatly reduce potential for problems no matter how your ground other accessories scattered about the airplane. Bob . . . ________________________________ Message 3 _____________________________________ Time: 09:21:10 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: CdS Photocell Holder/Fixture Hi All, I'm trying to locate a holder/fixture for a CdS photocell (http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PDV-P9203-ND) so that I can mount one on the panel. Google, Mouser, and Digikey searches just don't seem to be working for me. Thank you, /\/elson These devices are members of the family of parts intended to be components of a larger assembly. I don't recall ever seeing a "holder" for such devices. Building a holder is not difficult. Poke around in your local electronics supply houses including Radio Shack. You can probably find an existing product like . . . Emacs! that can be stripped of its innards and then modified to your purposes with the help of a little wire, solder and epoxy. Bob . . . ________________________________ Message 4 _____________________________________ Time: 09:56:17 AM PST US From: "David E. Nelson" Subject: Re: AeroElectric-List: CdS Photocell Holder/Fixture Hi Bob, I've seen some LED fixtures that just might fit the bill as you describe. Vi! Thank you, /\/elson ~~ Lately my memory seems to be like a steel trap .... without any spring. ~~ On Wed, 11 Aug 2010, Robert L. Nuckolls, III wrote: > > > Hi All, > > I'm trying to locate a holder/fixture for a CdS photocell ( http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PDV-P9203-ND ) so that I can mount one on the panel. Google, > Mouser, and Digikey searches just don't seem to be working for me. > > Thank you, > /\/elson > > These devices are members of the family > of parts intended to be components of a > larger assembly. I don't recall ever seeing > a "holder" for such devices. Building a holder > is not difficult. > > Poke around in your local electronics supply > houses including Radio Shack. You can probably > find an existing product like . . . > > Emacs! > > that can be stripped of its innards and > then modified to your purposes with the > help of a little wire, solder and epoxy. > > Bob . . . > > > ________________________________ Message 5 _____________________________________ Time: 10:35:56 AM PST US Subject: AeroElectric-List: Re: New Z-8 drawing From: "jonlaury" > Okay, we can press a 9024 into service as dual > LV warning only. Another 9024 would take care > of lv warning for both battery and main busses > PLUS ov protection for the S/B alternator. > I'm a little confused about the need for two 9024's if one can give LV indication for Batt and Main busses and OV protection from the stby alt. And would the OV protection extend to the shared contactor (stby alt/GPJ) for the ground power jack as in the attached? John Read this topic online here: http://forums.matronics.com/viewtopic.php?p=308387#308387 Attachments: http://forums.matronics.com//files/z8_w_sb_alt_gpj_conceptual__214.pdf ________________________________ Message 6 _____________________________________ Time: 04:31:55 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: New Z-8 drawing > >I'm a little confused about the need for two 9024's if one can give >LV indication for Batt and Main busses and OV protection from the stby alt. Oops, I had a brain-f@#t and was running the hampster wheel on another system. Got too many irons in the fire. I'm still stirring the pot on how to get the s/b alternator b-lead contactor to retain ground power reverse polarity and ov protection. The architecture you've illustrated agrees with my best recipe for the moment. Separate ov protection for the ground power contactor (probably crowbar) and another for s/b alternator field (probably 9024 driving a relay so you don't need a circuit breaker). >And would the OV protection extend to the shared contactor (stby >alt/GPJ) for the ground power jack as in the attached? We need to think about how the crowbar ov module interacts with the 9024 ov protection. We don't want the contactor to open before the ov relay gets tripped. I think we'll want to wire things so that the crowbar module is effective only while the ground power control switch/breaker is closed. I.e. move the black wire to the cathode end of the diode in the ground power control lead. Bob . . . ________________________________ Message 7 _____________________________________ Time: 11:21:15 PM PST US Subject: AeroElectric-List: Re: New Z-8 drawing From: "jonlaury" > Oops, I had a brain-f@#t and was running the > hampster wheel on another system. Got too many > irons in the fire. No worries and I know that I speak for all of us on this forum; it is simply astounding that you manage to participate here as much as you do AND keep your day job. > I think we'll want to wire > things so that the crowbar module is effective only > while the ground power control switch/breaker is > closed. I.e. move the black wire to the cathode > end of the diode in the ground power control lead. > OK, that's done in the attached. I quarantined the 9005 module for now until OV protection and LV monitoring gets ironed out. With 9024 control of the SB alt, I deleted the fuselink from the Batt bus in favor of a 5a fuse. Re the Main bus, with an LR3 in there, it seems that the main bus is taken care of and it's not necessary to integrate the SB alt 9024 voltage monitoring into the main bus. Can a 9024 now focus solely on the SB alt and battery bus? John Read this topic online here: http://forums.matronics.com/viewtopic.php?p=308465#308465 Attachments: http://forums.matronics.com//files/z8_w_sb_alt_gpj_conceptual__345.pdf ------------------------------------------------------------------------------------- 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.