---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 02/29/08: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:00 AM - Re: Question about panel light dimmers (Eric M. Jones) 2. 05:48 PM - Re: Re: Low voltage indicator for LR3 (Robert L. Nuckolls, III) 3. 11:10 PM - New toy in the AEC shop . . . (Robert L. Nuckolls, III) 4. 11:50 PM - Re: New toy in the AEC shop . . . (n801bh@netzero.com) ________________________________ Message 1 _____________________________________ Time: 08:00:13 AM PST US Subject: AeroElectric-List: Re: Question about panel light dimmers From: "Eric M. Jones" A very good explanation of how voltage regulators, both switching and linear, work is contained in: http://www.national.com/appinfo/power/files/f4.pdf But it should be said that 1.5A does not mean there is any margin above than at all--NONE. Otherwise it would be called a 1.6 Amp (or whatever)regulator. There are protection circuits onboard, but they DO DEPEND on some operating conditions being met. This is not always clear to the designer. I sell tons of 1.5A LM317-based voltage regulators (EGPAVR) on my website. I have also made these in slightly larger 2A and 3A versions. Above a few amps the game goes to switching regulators. BUT!!, in my humble opinion, there is a large zone where a larger, heavier, linear regulator is still preferable, since it is more reliable AND is electrically quiet. I have abandoned the use of switching regulators in some of my applications for this reason. Yes, squelching the RFI/EMI is possible, but why bother? I have seen some LED dimmers that are just horrendous. They use switching regulators with variable frequencies. They are guaranteed to induce wild hallucinatory visions in high-vibration environments.... Like chewing on hard candy while looking at a computer monitor. -------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge, MA 01550 (508) 764-2072 emjones@charter.net Read this topic online here: http://forums.matronics.com/viewtopic.php?p=166909#166909 ________________________________ Message 2 _____________________________________ Time: 05:48:09 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Low voltage indicator for LR3 > >I am wiring per Z-13/8. > >If I have a main alternator failure, the LR-3 indicator will tell me. >I switch on the Endurance bus and switch off the main bus, the >indicator will go out, since there is no power there at all. Yes, but this is a plan-B activity that is only expected to be implemented in case of a rare event . . . failure of the main alternator. >At this point, I need to switch on the aux alternator. As drawn, >there is no low voltage indicator to show if this alternator is >working. In an emergency, I might forget to do this. Failure of the main alternator is not an emergency. It's an emergency only if you have no alternatives i.e, you have no back up engine driven power source and you haven't the foggiest notion of how long your battery will run goodies in the endurance mode. > I usually good >with checklists, but an indicator would be helpful. How about a voltmeter. Does one of your relatively low power digital panel-wiggets have a voltmeter function? >This also means there are 3 switches I could accidentally leave on >after a flight or maintenance that would ensure a depleted battery >before the next flight. Are there no electro-whizzies on the panel that stay lit up when the endurance bus is hot? . . . and three switches? What's going to stay on un-annunciated besides the e-bus alternate feed switch? Oh, yeah, the aux alternator switch being left on would leave a hundred+ millamps of draw on the battery. >I could have 3 indicators for the switches and 2 low voltage >indicators. However, I really only need 1 indicator that indicates >low voltage in flight while running on either alternator, acting as an >idiot light after shutdown. >By adding another pole to the endurance bus and aux alternator >switches (main bus already has a usable switched to ground pole on its >switch), I can easily sense the switch positions. However, to avoid >an indicator continuously lit in flight, these contacts need to >activate a low voltage detector with a threshold abow the normal >battery voltage, but below the charging voltage. > >So depending on the value of the internal resistor driving the gate of >the FET, it could turn on my LED, which is essentially pulled to >ground from battery voltage through a 680 ohm resistor. I think you're making this more complicated than it needs to be. If the scenario that creates the situation you're guarding against happens every fifth flight, there's a significant human factors consideration for adding the extra indication/warning features. But your adding "stuff" to a system to remind you that you've just experienced a main alternator failure. Therefore, in addition a need for getting out the toolbox after you land, you need additional reminding to shut off the aux alternator and e-bus alternate feed switches? I considered low voltage warning lights for the e-bus architecture some years ago but decided against it. Flying on the e-bus only whether supported by the SD-8 or not is an extra-ordinary happening. An event that should cause give the pilot a heightened awareness of protocols for a sweat-free termination of the flight. Bob . . . ________________________________ Message 3 _____________________________________ Time: 11:10:54 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: New toy in the AEC shop . . . Since I no longer enjoy access to the labs at H-B, I've been gathering some useful tools up to enhance our development in the 'Connection's shops. I picked this temperature chamber up off Ebay a few weeks ago for $150 and paid another $150 to have it shipped! It's a little bigger brother to the very first chamber I bought at Electro-Mech about 30 years ago! Had to do a some work with door seals, CO2 plumbing and much scrubbing with 409 and acetone but it cleaned up pretty well. Just got it operational and tested. Gets down to -60C in about 20 minutes, back up to 80C in under 15 minutes and controls to within 2 degrees C. http://www.aeroelectric.com/Pictures/Tools/Temperature_Chamber_2.jpg I think it will do for the moment to get some work out for a customer this weekend. I've found a modern digital device to replace the analog heating/cooling controller. I'll replace the Fluke portable thermocouple readout with a permanent digital display and selector switch for about 5 channels of thermocouple. I need to build a CO2 valve-open timer so that I tell when a bottle is about to go empty. This thing uses the liquid CO2 from bottles with dip tubes. They're essentially constant pressure until the liquid runs out whereupon you loose cooling very quickly. But by monitoring total valve-open time I can get a pretty good calibration on pounds of CO2 consumed. Hmmmm . . . wonder if I need to hit up Mr. Gore for some carbon-credits. I'm going to dump about 100# of CO2 this weekend. Maybe I'd better get him to plant some trees for me or something. I'd forgotten how heavy those bottles are! I think I'll run a hard line from the garage down to the basement shop so I don't have to lug them on the stairs! I'm getting too old for that kind of work! You can even warm TV dinners in it! Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 4 _____________________________________ Time: 11:50:21 PM PST US From: "n801bh@netzero.com" Subject: Re: AeroElectric-List: New toy in the AEC shop . . . That rig should be very benificial in testing componants. Great buy Bob. .. Now for some comedy... If you do heat up TV dinners in it and you get the runs from bad beef does one need to purchase a new rectumfier or ju st recaliberate the old one ?? :< )).......... do not archive Ben Haas N801BH www.haaspowerair.com -- "Robert L. Nuckolls, III" wrote: olls.bob@cox.net> Since I no longer enjoy access to the labs at H-B, I've been gathering some useful tools up to enhance our development in the 'Connection's shops. I picked this temperature chamber up off Ebay a few weeks ago for $150 and paid another $150 to have it shipped! It's a little bigger brother to the very first chamber I bought at Electro-Mech about 30 years ago! Had to do a some work with door seals, CO2 plumbing and much scrubbing with 409 and acetone but it cleaned up pretty well. Just got it operational and tested. Gets down to -60C in about 20 minutes, back up to 80C in under 15 minutes and controls to within 2 degrees C. http://www.aeroelectric.com/Pictures/Tools/Temperature_Chamber_2.jpg I think it will do for the moment to get some work out for a customer this weekend. I've found a modern digital device to replace the analog heating/cooling controller. I'll replace the Fluke portable thermocouple readout with a permanent digital display and selector switch for about 5 channels of thermocouple. I need to build a CO2 valve-open timer so that I tell when a bottle is about to go empty. This thing uses the liquid CO2 from bottles with dip tubes. They're essentially constant pressure until the liquid runs out whereupon you loose cooling very quickly. But by monitoring total valve-open time I can get a pretty good calibration on pounds of CO2 consumed. Hmmmm . . . wonder if I need to hit up Mr. Gore for some carbon-credits. I'm going to dump about 100# of CO2 this weekend. Maybe I'd better get him to plant some trees for me or something. I'd forgotten how heavy those bottles are! I think I'll run a hard line from the garage down to the basement shop so I don't have to lug them on the stairs! I'm getting too old for that kind of work! You can even warm TV dinners in it! Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ======================== =========== ======================== =========== ======================== =========== ======================== =========== _____________________________________________________________ Best Commodity Trading Platforms. Click Now! http://thirdpartyoffers.netzero.net/TGL2221/fc/Ioyw6i4tFCb31fHvhXyd1D3o0 4B4xMThNcWFXgexEfHscpFLuAYo8R/ ------------------------------------------------------------------------------------- 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.