---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 12/21/07: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:31 AM - Re: Amp 59250 t-head tool (Robert L. Nuckolls, III) 2. 06:52 AM - Eclispe crimping tool? (earl_schroeder@juno.com) 3. 07:19 AM - Re: Amp 59250 t-head tool (BobsV35B@aol.com) 4. 07:34 AM - Re: Eclispe crimping tool? (Robert L. Nuckolls, III) 5. 07:35 AM - Re: Alternator whine in audio (Robert L. Nuckolls, III) 6. 07:43 AM - Re: swapping two radios using 3P/DT switch? (Robert L. Nuckolls, III) 7. 09:07 AM - swapping two radios using 3P/DT switch? (BUCSDDS@aol.com) 8. 02:08 PM - Re: Alternator whine in audio (Robert Feldtman) 9. 02:46 PM - Yahoo! Auto Response (jpiamber@yahoo.com) 10. 03:54 PM - Re: Firewall Placement Of Electrical Components (Robert L. Nuckolls, III) 11. 04:42 PM - Re: 20 Amp Solid State Relay usage (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:31:28 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Amp 59250 t-head tool At 10:25 AM 12/20/2007 -0500, you wrote: >Good Morning 'Lectric Bob, > >You mentioned once that you had sent your T head crimper in for a rebuild. >Do you know if such a service is still available? > >If so, where and how much ? I don't know. That would have been about 1965! I got the address of the rebuild shop from a guy in a toolcrib at the Cessna East Pawnee plant who was responsible for tool screening and maintenance. After having bought a "worn out" tool from Cessna salvage for $25, it was a long step to add another $50 or so to that to make it a zero time tool! You can search the Tyco-Amp for "refurbish" or "rebuild" services. Bob . . . ________________________________ Message 2 _____________________________________ Time: 06:52:42 AM PST US From: "earl_schroeder@juno.com" Subject: AeroElectric-List: Eclispe crimping tool? Hi Bob [or other contributors], I purchased the crimping tool referenced in this URL: http://www.mpja.com/prodinfo.asp?number=15534+TL However, it came with no instructions or illustrations as to its use. I suppose I could use trial and error but prefer some helpful hints. Thanks, Earl PS searching the archives, produced none that I could find. _____________________________________________________________ Online Stock Trading - Straightforward pricing. Powerful tools. Click here! http://thirdpartyoffers.juno.com/TGL2121/fc/Ioyw6i3mJ8X0xeveOtvWEDbDHQb3OPK9ixAAfti9QiZFE9N30DXS3n/ ________________________________ Message 3 _____________________________________ Time: 07:19:05 AM PST US From: BobsV35B@aol.com Subject: Re: AeroElectric-List: Amp 59250 t-head tool Thanks Bob, I'll get on it! (sometime that is.) Happy Skies, Old Bob In a message dated 12/21/2007 8:33:35 A.M. Central Standard Time, nuckolls.bob@cox.net writes: I don't know. That would have been about 1965! I got the address of the rebuild shop from a guy in a toolcrib at the Cessna East Pawnee plant who was responsible for tool screening and maintenance. After having bought a "worn out" tool from Cessna salvage for $25, it was a long step to add another $50 or so to that to make it a zero time tool! You can search the Tyco-Amp for "refurbish" or "rebuild" services. Bob . . . **************************************See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004) ________________________________ Message 4 _____________________________________ Time: 07:34:40 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Eclispe crimping tool? At 02:50 PM 12/21/2007 +0000, you wrote: > > >Hi Bob [or other contributors], >I purchased the crimping tool referenced in this URL: >http://www.mpja.com/prodinfo.asp?number=15534+TL > >However, it came with no instructions or illustrations as to its use. > >I suppose I could use trial and error but prefer some helpful hints. > >Thanks, Earl > >PS searching the archives, produced none that I could find. It's pretty straight-forward. You need to strip the wire just enough that the strands bottom out in the back of the pin just before the insulation touches the pin. Hold the wire/pin up vertically and drop the tool over it until the pin is fully seated in the tool. The pin will be flush to just underflush with the working face of the tool. Put the mash on it an you're done. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 5 _____________________________________ Time: 07:35:35 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Alternator whine in audio At 04:20 PM 12/20/2007 +0000, you wrote: >Hello All,"urn:schemas-microsoft-com:office:office" /> > > I have a PlanePower alternator and have noticed a whine noise in the > David Clark headset audio. It is really noisy if the headset volume is > high; however, if I turn the headset volume down low and turn the comm > radio volume up to compensate, the whine is barely detectable. Can anyone > explain this and/or provide possible solutions? Yes. The alternator is the noisiest device in the airplane and there is no practical way to 'filter' its worst noise component - AC 'ripple' voltage left over after the 3-phase AC output of the stator windings is rectified into DC. The simple-ideas that support this assertion are illustrated in an excerpted figure from the chapter on noise in the 'Connection which you can see here: http://www.aeroelectric.com/Pictures/Misc/Figure_16p3.pdf A rectified 3-phase AC voltage has a predictable 10% pk-pk ripple. I.e., your 14V alternator has about 1.4 volts pk-pk AC signal at an audio rate (you can hear it) riding on top of the DC power output. Worse yet, the ENERGY in this 'noise' is HUGE . . . let's say .5v RMS X alternator output of up to say 60A makes this a 30 WATT potential noise source. The notion of adding a practical filter for this condition is polluted by the knowledge that many of the more useful filters for radio noise are fairly easy pills to swallow (.5 lb, 10 square inches footprint and perhaps 30 cubic inches in volume). However, these are designed to work at Megahertz frequencies and energy levels perhaps 1 millionth as strong. A filter capable of cleaning up the output of an alternator is going to be more weight, volume and loss of power than you're going to want to put in your airplane. This is why the graybeards in this technology have provided guidance to designers in the form of Mil-Std-704 and similar tomes that say, "Son, that's one nasty noise generator out there on the engine with no practical way to silence it. Suggest you learn to live with it." Indeed, DC power generation per Mil-Std-704 tells us to expect 3 volts pk-pk on 28v systems as described in http://www.aeroelectric.com/Pictures/Curves/MSTD704_28V_Noise.jpg over the range of 1000 to 5000 Hz (you can HEAR it) and tapering in intensity on either side. Cut that value in half for a 14v system. Here's a noise trace taken from my automobile's bus: http://www.aeroelectric.com/Pictures/Curves/Safari_Bus_Noise_1.gif >I called PlanePower to inquire about filter and they informed me that >their product has internal noise filtering and that I must have an audio >ground problem. But they didn't tell you everything. The only kind of filter that can be physically installed in their alternator goes to conducted RADIO FREQUENCY noise from 150 KHz to 30 MHz in the form of a reasonably sized capacitor. This filter cannot speak to the AUDIO FREQUENCY noise described in the Mil-Std-704 excerpt cited above. Their hypothesis about audio ground noise is a strong one. The vast majority of audio system noise problems I've encountered in the past had root cause in poor ground architecture. This is why we spend so much time exploring the potential for grounding problems in chapter 16 and crafted the ground architecture drawings in Figure Z-15. > When the alternator is switched off-line, the audio is crystal clear. If > there was an > audio grounding issue I would expect to hear ignition noise too, but > that's not > the case. A faulty supposition. The propagation modes for these two antagonists are entirely different from each other. The presence of one does not automatically include or exclude the presence of both. >Can additional filtering be installed external to the alternator? No. > Suggestions please. Suggest you first make sure that your headset and microphone jacks DO NOT ground locally to the airframe where they are mounted. This common installation error probably accounts for 1/2 of all the light aircraft alternator noise problems. Understand too that you MIGHT have a propagation mode that is difficult to find and/or fix. With the advent of high quality, noise cancelling headsets noises that used to be well below the nuisance threshold for signal to noise are now deemed undesirable. I'm not suggesting that your problem is not fixable . . . just that the cost in $time$ to fix it may not be very rewarding. Is the noise you're hearing on the ground perceptible and objectionable in flight? I've had MANY situations where folks have chased over an airplane looking for root cause and fix for noises that nobody can hear while in flight. If the mic/headset jacks ARE properly grounded back at the intercom, then try running the noise isolation traps described in Chapter 16. The noise MIGHT be coming in through the +14v power leads where its practical to add a filter like: http://www.aeroelectric.com/articles/filter/RS_Noise_Filters.pdf http://www.aeroelectric.com/articles/filter/filter.pdf Unfortunately, all the components featured in these two pieces are no longer offered by Radio Shack since they got out of the automotive audio products business. However, other companies are very much IN that business. If your studies determine that the noise IS coming in through the +14v supply, perhaps a device like . . . http://tinyurl.com/ynn7at would do the job. There's no automatic recipe for success here because the variables that set levels of perception for the noise have a huge range of cause/effect. Noise problems of this nature are always plagued with a certain amount of cut and try. I've copied my friend Steven Klodd at Plane-Power on this note. Steve, should you find it useful, feel free to copy any or all of this stuff and assemble it into a document for sharing with your customers. A poor understanding of these simple- ideas has cause our brothers to spend a lot of $time$ chasing the elusive double-ugly, yellow- beaked noise snipe! Bob . . . ________________________________ Message 6 _____________________________________ Time: 07:43:17 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: swapping two radios using 3P/DT switch? At 12:09 PM 12/20/2007 -0800, you wrote: >Bob and/or other electronics gurus-- > >I'm using revision 11 and looking at chapter 11 (switches) and also the >FAQ's...I have attached an excerpt from the FAQ's that I think applies to >my question as well...it's a gentleman inquiring about using either a >"3PDT" switch (I think numerically this is a "3-3 switch"?) to change >between two comm radios. > >If I have a panel mount comm radio (with it's own antenna) and a portable >comm radio (an SP-200 with it's own antenna) and a simple two-place >intercom system (i.e. PM 3000), I believe I need the above referenced >three-pole double-throw (3-3) switch to swap between the two radios: a >pole for the wire going to the headset earphones, a pole for the wire >coming from the headset microphone, and a pole to swap the PTT line. By >doing this, I can swap radios without having to go through the intercom >system which is in-line with your philosophy (which I agree with) of >minimizing knob-twisting distractions. I don't see any examples of triple >pole switches in the book and I can't find any in the Spruce catalog, but >if I'm thinking correctly, do you have a suggested resource for obtaining >one? Otherwise is there another switching logic I should consider? Once >again, everyone please feel free to shoot holes in my ideas. Thanks. > >Lincoln Keill >Sacramento, CA Check out the C&K 7301P3YZQE switch at: http://tinyurl.com/ypqomr and http://www.aeroelectric.com/Pictures/Switches/7301P3YZQE.jpg Bob . . . ________________________________ Message 7 _____________________________________ Time: 09:07:00 AM PST US From: BUCSDDS@aol.com Subject: AeroElectric-List: swapping two radios using 3P/DT switch? Bob or anyone else with the correct answer to my question, I have an issue with my Headset/PTT/Microphone wiring. I have a Garmin SL-30, SL-40 and the PMA 4000 by PS Engineering intercom. I hear a squeal when I press the PTT switch. If the intercom is turned off the squeal doesn't occur while pressing the PTT switch. I'm wondering if a 3P/DT switch would be a good option. If so, what schematic should I use?? Thanks in advance for any help! Marwin Goff Des Moines, IA Marwin Goff DSM Varieze O-200 515-360-0778 bucsdds@aol.com **************************************See AOL's top rated recipes (http://food.aol.com/top-rated-recipes?NCID=aoltop00030000000004) ________________________________ Message 8 _____________________________________ Time: 02:08:53 PM PST US From: "Robert Feldtman" Subject: Re: AeroElectric-List: Alternator whine in audio there are noise filters in the amateur radio realm that work reasonably well..... I am thinking about trying that in my audio ciruit to headphone to see if I could "tune out" the noise. Any pilots using those? You can see them advertised in QST, etc. bobf Glastar W5RF On 12/21/07, Robert L. Nuckolls, III wrote: > > nuckolls.bob@cox.net> > > At 04:20 PM 12/20/2007 +0000, you wrote: > > >Hello All, >"urn:schemas-microsoft-com:office:office" /> > > > > I have a PlanePower alternator and have noticed a whine noise in the > > David Clark headset audio. It is really noisy if the headset volume is > > high; however, if I turn the headset volume down low and turn the comm > > radio volume up to compensate, the whine is barely detectable. Can > anyone > > explain this and/or provide possible solutions? > > Yes. The alternator is the noisiest device in the > airplane and there is no practical way to 'filter' > its worst noise component - AC 'ripple' voltage > left over after the 3-phase AC output of the stator > windings is rectified into DC. > > The simple-ideas that support this assertion are > illustrated in an excerpted figure from the chapter > on noise in the 'Connection which you can see > here: > > http://www.aeroelectric.com/Pictures/Misc/Figure_16p3.pdf > > > A rectified 3-phase AC voltage has a predictable > 10% pk-pk ripple. I.e., your 14V alternator has > about 1.4 volts pk-pk AC signal at an audio rate > (you can hear it) riding on top of the DC power > output. Worse yet, the ENERGY in this 'noise' > is HUGE . . . let's say .5v RMS X alternator > output of up to say 60A makes this a 30 WATT > potential noise source. > > The notion of adding a practical filter for this > condition is polluted by the knowledge that > many of the more useful filters for radio noise > are fairly easy pills to swallow (.5 lb, 10 square > inches footprint and perhaps 30 cubic inches > in volume). However, these are designed to work > at Megahertz frequencies and energy levels > perhaps 1 millionth as strong. > > A filter capable of cleaning up the output > of an alternator is going to be more weight, > volume and loss of power than you're going > to want to put in your airplane. > > This is why the graybeards in this technology > have provided guidance to designers in the form > of Mil-Std-704 and similar tomes that say, "Son, > that's one nasty noise generator out there on > the engine with no practical way to silence it. > Suggest you learn to live with it." > > Indeed, DC power generation per Mil-Std-704 > tells us to expect 3 volts pk-pk on 28v systems > as described in > > http://www.aeroelectric.com/Pictures/Curves/MSTD704_28V_Noise.jpg > > over the range of 1000 to 5000 Hz (you can HEAR > it) and tapering in intensity on either side. > Cut that value in half for a 14v system. Here's > a noise trace taken from my automobile's bus: > > http://www.aeroelectric.com/Pictures/Curves/Safari_Bus_Noise_1.gif > > >I called PlanePower to inquire about filter and they informed me that > >their product has internal noise filtering and that I must have an audio > >ground problem. > > But they didn't tell you everything. The only kind > of filter that can be physically installed in their > alternator goes to conducted RADIO FREQUENCY noise > from 150 KHz to 30 MHz in the form of a reasonably > sized capacitor. This filter cannot speak to the > AUDIO FREQUENCY noise described in the Mil-Std-704 > excerpt cited above. > > Their hypothesis about audio ground noise is a > strong one. The vast majority of audio system noise > problems I've encountered in the past had root > cause in poor ground architecture. This is why we > spend so much time exploring the potential for > grounding problems in chapter 16 and crafted the > ground architecture drawings in Figure Z-15. > > > When the alternator is switched off-line, the audio is crystal clear. > If > > there was an > > audio grounding issue I would expect to hear ignition noise too, but > > that's not > > the case. > > A faulty supposition. The propagation modes for > these two antagonists are entirely different from > each other. The presence of one does not automatically > include or exclude the presence of both. > > >Can additional filtering be installed external to the alternator? > > No. > > > Suggestions please. > > Suggest you first make sure that your headset > and microphone jacks DO NOT ground locally to > the airframe where they are mounted. This common > installation error probably accounts for 1/2 of > all the light aircraft alternator noise problems. > > Understand too that you MIGHT have a propagation > mode that is difficult to find and/or fix. With > the advent of high quality, noise cancelling > headsets noises that used to be well below the > nuisance threshold for signal to noise are now > deemed undesirable. I'm not suggesting that your > problem is not fixable . . . just that the cost > in $time$ to fix it may not be very rewarding. > > Is the noise you're hearing on the ground perceptible > and objectionable in flight? I've had MANY situations > where folks have chased over an airplane looking > for root cause and fix for noises that nobody > can hear while in flight. > > If the mic/headset jacks ARE properly grounded > back at the intercom, then try running the noise > isolation traps described in Chapter 16. The noise > MIGHT be coming in through the +14v power leads > where its practical to add a filter like: > > http://www.aeroelectric.com/articles/filter/RS_Noise_Filters.pdf > > http://www.aeroelectric.com/articles/filter/filter.pdf > > Unfortunately, all the components featured in > these two pieces are no longer offered by Radio > Shack since they got out of the automotive audio > products business. However, other companies > are very much IN that business. If your studies > determine that the noise IS coming in through the > +14v supply, perhaps a device like . . . > > http://tinyurl.com/ynn7at > > would do the job. There's no automatic recipe > for success here because the variables that set > levels of perception for the noise have a huge > range of cause/effect. Noise problems of this > nature are always plagued with a certain amount > of cut and try. > > I've copied my friend Steven Klodd at Plane-Power > on this note. Steve, should you find it useful, > feel free to copy any or all of this stuff and > assemble it into a document for sharing with your > customers. A poor understanding of these simple- > ideas has cause our brothers to spend a lot of > $time$ chasing the elusive double-ugly, yellow- > beaked noise snipe! > > Bob . . . > > ________________________________ Message 9 _____________________________________ Time: 02:46:48 PM PST US From: jpiamber@yahoo.com Subject: AeroElectric-List: Yahoo! Auto Response JPI will be closed to observe Christmas December 22ND and will return on December 27TH. JPI will be closed to observe the New Year Holiday December 29TH and will return on January 2ND. The holiday season offers us a special opportunity to extend our personal thanks to our friends, and our very best wishes for the future. And so it is that we now gather together and wish to you a very Merry Christmas and a Happy New Year. We consider you a good friend and extend our wishes for good health and good cheer. It is people like you who make being in business such a pleasure all year long. Our business is a source of pride to us, and with customers like you, we find going to work each day a rewarding experience. To our friends all over the world, JP Instruments extends to you and your loved ones our best wishes for a Vrolijke Kersttmis Sarbatori Felicite Joyeux Noel Tin Hao Nian Froeliche Weihnachten Felice Natale Kinga Shinnen Glad Julen Ichok Yilara Boas Festas Chrustovjna Wesloych Swiat Glaedelig Jul Veselele Vanoche Felice Pascuas Sretan Bozic Boldog Karacsonyi Unnepeket Merry Christmas and a Happy New Year! ________________________________ Message 10 ____________________________________ Time: 03:54:25 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Firewall Placement Of Electrical Components At 08:39 AM 12/20/2007 -0800, you wrote: > > >I am building a Zenith 601 and using a variation of the Z16 drawing. I am >currently working on placing my regulator, S704-1 OV relay and >capacitor. The B&C instructions are pretty clear that this stuff should >be mounted on the cockpit side of the firewall and away from engine >heat. In this configuration, the Z16 would have me running a 12GA from >the capacitor, through the firewall, and out to the up-leg screw on the >starter relay. I would also have a 12GA going from the down-leg screw of >the battery relay, through the firewall, and to the main distribution >bus. My question is two-fold: > >1. Is it critical that these electrical parts be on the backside of the >firewall. I have seen photos of this stuff on the engine side on other >airplanes. Everyone likes to "stay cool" but virtually every product I design these days is required to live and work in a 55C environment minimum and virtually all our stuff can be demonstrated to run up to 100C. Lots of folks have installed the B&C products and the products of others on the engine side of the firewall with no complaints. Your risks are low. >2. If I follow B&C's recommendation on placement, can I run the >alternator lead from the capacitor straight to the main distribution >bus? This would only require one 12GA wire firewall penetration from the >bus to the battery relay. If it's a cleaner installation to go up front, go ahead and do it. Bob . . . ________________________________ Message 11 ____________________________________ Time: 04:42:09 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: 20 Amp Solid State Relay usage At 02:34 PM 12/10/2007 -0700, you wrote: > >I too am using the AML34 and AML24 switches in my panel. Pacific Coast >Avionics recommended using the Potter Brumfield VF4-65F11 relays for higher >loads. > >Any thoughts on these relays Bob? Are they reliable enough? "Reliable enough" isn't quantifiable . . . if you use them with failure tolerant design in mind, then any component demonstrating a service life commensurate with your $time$ to acquire/install/maintain will have no serious effect on system reliability, only a cost of ownership consideration. The plastic automotive power relays are in widespread usage throughout the industry. Chances are that they're entirely suited to your task of crafting the failure tolerant system. 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