---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 09/09/11: 22 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:01 AM - AeroLed landing lights not working with wig wag relay (Helidesigner) 2. 05:05 AM - Lithium Batteries? (Andrew Zachar) 3. 05:24 AM - Re: AeroLed landing lights not working with wig wag relay (Andrew Zachar) 4. 06:19 AM - Re: AeroLed landing lights not working with wig wag relay (Robert L. Nuckolls, III) 5. 06:36 AM - Re: Lithium Batteries? (Robert L. Nuckolls, III) 6. 08:50 AM - Re: AeroLed landing lights not working with wig wag relay () 7. 10:38 AM - Halogen bulbs with wig wag circuitry....failure mode (David Lloyd) 8. 11:19 AM - Re: Halogen bulbs with wig wag circuitry....failure mode (Bruce) 9. 01:57 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (David Lloyd) 10. 03:49 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (Bruce) 11. 04:19 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (Robert L. Nuckolls, III) 12. 05:52 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (David Lloyd) 13. 05:54 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (David Lloyd) 14. 06:09 PM - RF noise from Jeff's LED lights (Bill Watson) 15. 07:22 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (Bob McCallum) 16. 08:03 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (Vern Little) 17. 09:10 PM - Low Cost WigWag Alternatives (Paul Zimmer) 18. 09:24 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (B Tomm) 19. 10:41 PM - Re: AeroLed landing lights not working with wig wag relay (jerb) 20. 10:58 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (David Lloyd) 21. 11:02 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (David Lloyd) 22. 11:05 PM - Re: Halogen bulbs with wig wag circuitry....failure mode (David Lloyd) ________________________________ Message 1 _____________________________________ Time: 05:01:27 AM PST US Subject: AeroElectric-List: AeroLed landing lights not working with wig wag relay From: "Helidesigner" I purchased the B&C wig wag relay and wired it according to the schematic for an off-on-on switch and B&C diode assembly. The wig-wag is in the middle position. I included the resistors between the relay and ground shown in the updated schematic. The system works fine with incandecent nav lights but not with the LED landing lights. Only one LED light turns on in wig wag mode and both lights turn on in continuous on mode. The nav lights draw about 3.2 amps, the LED lights about 3.7 amp. Anyone know what is going on here and how to fix it. Should I just purchase an electronic wig wag unit designed for LED's? -------- Thanks Read this topic online here: http://forums.matronics.com/viewtopic.php?p=351786#351786 ________________________________ Message 2 _____________________________________ Time: 05:05:54 AM PST US Subject: AeroElectric-List: Lithium Batteries? From: Andrew Zachar Good morning, Bob. I was wondering if you had any thoughts on the use of lithium batteries in OBAM aircraft. (http://www.lithiumaviationbattery.com/) (We're starting to see a lot of certification efforts for them around Wichita, Albuquerque, Savannah, other places on the east coast...) -- Andrew Zachar andrew.d.zachar@gmail.com ________________________________ Message 3 _____________________________________ Time: 05:24:25 AM PST US Subject: Re: AeroElectric-List: AeroLed landing lights not working with wig wag relay From: Andrew Zachar If I recall, the B&C flasher will only cycle if it sees a load. I bet the LEDs aren't drawing enough for the B&C to recognize that you actually have two lights hooked up... Sorry I'm not knowledgeable enough to offer a solution. On Fri, Sep 9, 2011 at 7:56 AM, Helidesigner wrote: > mwscott2@comcast.net> > > I purchased the B&C wig wag relay and wired it according to the schematic > for an off-on-on switch and B&C diode assembly. The wig-wag is in the middle > position. I included the resistors between the relay and ground shown in > the updated schematic. The system works fine with incandecent nav lights but > not with the LED landing lights. Only one LED light turns on in wig wag mode > and both lights turn on in continuous on mode. The nav lights draw about 3.2 > amps, the LED lights about 3.7 amp. Anyone know what is going on here and > how to fix it. Should I just purchase an electronic wig wag unit designed > for LED's? > > -------- > Thanks > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=351786#351786 > > -- Andrew Zachar andrew.d.zachar@gmail.com ________________________________ Message 4 _____________________________________ Time: 06:19:35 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: AeroLed landing lights not working with wig wag relay At 07:56 AM 9/9/2011, you wrote: > >I purchased the B&C wig wag relay and wired it according to the >schematic for an off-on-on switch and B&C diode assembly. The >wig-wag is in the middle position. I included the resistors between >the relay and ground shown in the updated schematic. The system >works fine with incandecent nav lights but not with the LED landing >lights. Only one LED light turns on in wig wag mode and both lights >turn on in continuous on mode. The nav lights draw about 3.2 amps, >the LED lights about 3.7 amp. Anyone know what is going on here and >how to fix it. Should I just purchase an electronic wig wag unit >designed for LED's? I modified that drawing for B&C based on testing I did using one of the flashers from their inventory. The resistors were added to emulate the fixed load offered by incandescent lamps. You are the second individual who was unable to duplicate the behavior I was getting on the bench. I have a pair of Whelen LED landing lights loaned to me by another reader and I plotted their current draw vs. voltage curve which I posted on the List a few days ago. I'm somewhat tied up with some family matters and can't get back to the bench right now to figure out what's going on . . . but the solution will not be difficult. Sit tight for the moment . . . watch this space. Bob . . . ________________________________ Message 5 _____________________________________ Time: 06:36:27 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Lithium Batteries? At 08:02 AM 9/9/2011, you wrote: >Good morning, Bob. > >I was wondering if you had any thoughts on the use of lithium >batteries in OBAM aircraft. >(http://www.lithiumaviationbattery.com/) > >(We're starting to see a lot of certification efforts for them >around Wichita, Albuquerque, Savannah, other places on the east coast...) I've not had any conversation with the lithium battery program manager at HBC in a couple of years. I'll drop him a note and see if there's anything close to getting onto a type certificate. This is one area where the OBAM aircraft owner is justified in a wait-and-see response. It isn't like you can't go flying without a lithium battery. The ARE more expensive. They have fragilities and performance issues that may make their price difference still more unattractive. It would be useful to have some first-hand feedback from users. While the weight savings is compelling, they are not a drop-in replacement for RG in every respect. But if you're willing to be one of those users eager to share you own first-hand experiences, go for it. Bob . . . ________________________________ Message 6 _____________________________________ Time: 08:50:19 AM PST US From: Subject: Re: AeroElectric-List: AeroLed landing lights not working with wig wag relay Strange, from what I have seen of the AeroLEDs landing lights, there is no need for a separate circuit for wing-wag. The units already have that circuitry and functionality built in. Do you have some older units that don=99t include that feature? From: Andrew Zachar Sent: Friday, September 09, 2011 5:19 AM Subject: Re: AeroElectric-List: AeroLed landing lights not working with wig wag relay If I recall, the B&C flasher will only cycle if it sees a load. I bet the LEDs aren't drawing enough for the B&C to recognize that you actually have two lights hooked up... Sorry I'm not knowledgeable enough to offer a solution. On Fri, Sep 9, 2011 at 7:56 AM, Helidesigner wrote: I purchased the B&C wig wag relay and wired it according to the schematic for an off-on-on switch and B&C diode assembly. The wig-wag is in the middle position. I included the resistors between the relay and ground shown in the updated schematic. The system works fine with incandecent nav lights but not with the LED landing lights. Only one LED light turns on in wig wag mode and both lights turn on in continuous on mode. The nav lights draw about 3.2 amps, the LED lights about 3.7 amp. Anyone know what is going on here and how to fix it. Should I just purchase an electronic wig wag unit designed for LED's? ________________________________ Message 7 _____________________________________ Time: 10:38:50 AM PST US From: "David Lloyd" Subject: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode A general question for Bob and the List Members concerning halogen bulbs, i.e., GE H7604 landing light style. I am hoping someone on the List knows a lot about halogen bulb failure modes. I have H7604 lamps in my wing tips that aid landing and traffic recognition. They are controlled by a solid state switcher that is either OFF-ON-PULSED. ( I do not know the turn-on ramp characteristics..) They fail in less than 10 hrs of operation. Interesting both seem to fail nearly at the same time. The "pulse" mode for traffic recognition is the major use. My ignorant guess is that halogen bulbs do not like to be pulsed or ramped up too quickly during pulse mode. If the rapid power ramp up is the primary cause, I am wondering if an appropriate choke (induction) would slow that ramping down and return normal life to these devices. Any insight, suggestions into the failure mode and how to work around it would be greatly appreciated. David ________________________________ Message 8 _____________________________________ Time: 11:19:46 AM PST US From: "Bruce" Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Switch to HID. Bruce WWW.Glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of David Lloyd Sent: Friday, September 09, 2011 1:31 PM Subject: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode A general question for Bob and the List Members concerning halogen bulbs, i.e., GE H7604 landing light style. I am hoping someone on the List knows a lot about halogen bulb failure modes. I have H7604 lamps in my wing tips that aid landing and traffic recognition. They are controlled by a solid state switcher that is either OFF-ON-PULSED. ( I do not know the turn-on ramp characteristics..) They fail in less than 10 hrs of operation. Interesting both seem to fail nearly at the same time. The "pulse" mode for traffic recognition is the major use. My ignorant guess is that halogen bulbs do not like to be pulsed or ramped up too quickly during pulse mode. If the rapid power ramp up is the primary cause, I am wondering if an appropriate choke (induction) would slow that ramping down and return normal life to these devices. Any insight, suggestions into the failure mode and how to work around it would be greatly appreciated. David ________________________________ Message 9 _____________________________________ Time: 01:57:54 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Good suggestion...all except for the considerable cost for dual sets..... David ____________________________________________________ ----- Original Message ----- From: "Bruce" Sent: Friday, September 09, 2011 11:16 AM Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > Switch to HID. > > Bruce > WWW.Glasair.org > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of David > Lloyd > Sent: Friday, September 09, 2011 1:31 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > > > A general question for Bob and the List Members concerning halogen > bulbs, > i.e., GE H7604 landing light style. > > I am hoping someone on the List knows a lot about halogen bulb failure > modes. > > I have H7604 lamps in my wing tips that aid landing and traffic > recognition. > They are controlled by a solid state switcher that is either > OFF-ON-PULSED. > ( I do not know the turn-on ramp characteristics..) > > They fail in less than 10 hrs of operation. Interesting both seem to > fail > nearly at the same time. The "pulse" mode for traffic recognition is > the > major use. > > My ignorant guess is that halogen bulbs do not like to be pulsed or > ramped > up too quickly during pulse mode. If the rapid power ramp up is the > primary > cause, I am wondering if an appropriate choke (induction) would slow > that > ramping down and return normal life to these devices. > > Any insight, suggestions into the failure mode and how to work around it > > would be greatly appreciated. David > > > ________________________________ Message 10 ____________________________________ Time: 03:49:48 PM PST US From: "Bruce" Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode OK, how about LED? Bruce WWW.Glasair.org -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of David Lloyd Sent: Friday, September 09, 2011 4:49 PM Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Good suggestion...all except for the considerable cost for dual sets..... David ____________________________________________________ ----- Original Message ----- From: "Bruce" Sent: Friday, September 09, 2011 11:16 AM Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > Switch to HID. > > Bruce > WWW.Glasair.org > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of David > Lloyd > Sent: Friday, September 09, 2011 1:31 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > > > A general question for Bob and the List Members concerning halogen > bulbs, > i.e., GE H7604 landing light style. > > I am hoping someone on the List knows a lot about halogen bulb failure > modes. > > I have H7604 lamps in my wing tips that aid landing and traffic > recognition. > They are controlled by a solid state switcher that is either > OFF-ON-PULSED. > ( I do not know the turn-on ramp characteristics..) > > They fail in less than 10 hrs of operation. Interesting both seem to > fail > nearly at the same time. The "pulse" mode for traffic recognition is > the > major use. > > My ignorant guess is that halogen bulbs do not like to be pulsed or > ramped > up too quickly during pulse mode. If the rapid power ramp up is the > primary > cause, I am wondering if an appropriate choke (induction) would slow > that > ramping down and return normal life to these devices. > > Any insight, suggestions into the failure mode and how to work around it > > would be greatly appreciated. David > > > ________________________________ Message 11 ____________________________________ Time: 04:19:01 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode I have H7604 lamps in my wing tips that aid landing and traffic recognition. They are controlled by a solid state switcher that is either OFF-ON-PULSED. ( I do not know the turn-on ramp characteristics..) They fail in less than 10 hrs of operation. Interesting both seem to fail nearly at the same time. The "pulse" mode for traffic recognition is the major use. My ignorant guess is that halogen bulbs do not like to be pulsed or ramped up too quickly during pulse mode. If the rapid power ramp up is the primary cause, I am wondering if an appropriate choke (induction) would slow that ramping down and return normal life to these devices. If I were to do a WAG . . . I'm guessing that you're getting repetitive stress cracks in the filaments. These things operate somewhat hotter than their older cousins . . . most seem to have heavier filaments too. There are two things that erode filament integrity . . . evaporation (total operating hours issue) and stress cracks (combination of vibration and temperature cycling). I'm wondering if the halogens are not more highly stressed during each illumination cycle. Since a wig-wag operates on the order of 2 flashes per second, 10 hours of flashing would offer 72,000 or so temperature cycles. Far more cycles than would be expected in automotive applications. Just assuming 200 cycles per day in a high-beam lamp for night highway driving would take 360 straight days of such service to equal 10 hours of wig-wag. Any insight, suggestions into the failure mode and how to work around it would be greatly appreciated. Not sure 'current ramping' would have a very useful effect. Some of you may recall an experiment we did some years back to evaluate the usefulness of inrush-limiters in wig-wagged landing lights. Remember this plot? http://www.aeroelectric.com/Pictures/Curves/Wig_Wag_Currents.jpg We discovered that the lamp temperature stays pretty warm during a 250 mS off-cycle such that you don't see the typical cold-filament inrush each time the lamp is powered up. But the temperature excursions between no-visible light and full intensity is still significant. It may well be that the very thing that makes the halogen a stellar illuminator amongst incandescent lamps is it's Achilles Heel as well. Just a guess . . . but until I hear/get a better idea, I'm sticking with it. Bob . . . ________________________________ Message 12 ____________________________________ Time: 05:52:29 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Bob, I think that you are totally correct concerning the thermo rapid cycle being the stress failure mode. When viewing the filaments with a mag. lens they look completely normal and intact until you look carefully at one end of the filament. They are broken at the very end. Odd that I have not run into others that are having the same problem as these bulbs are used in a lot of recognition applications. I suspect that if I left them ON continually, they would last a normal life. And, as you outline, in PULSE mode the thermo aspect is too much stress. I wonder now, if there is a heavy duty version of this bulb with bullet proof filament structure. I am installing new bulbs when delivered and will report back when I have a similar failure. Hopefully, I may have learned more. Thanks, David ___________________________________________________________________________ ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Friday, September 09, 2011 4:15 PM Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > > I have H7604 lamps in my wing tips that aid landing and traffic > recognition. They are controlled by a solid state switcher that is either > OFF-ON-PULSED. ( I do not know the turn-on ramp characteristics..) > > They fail in less than 10 hrs of operation. Interesting both seem to fail > nearly at the same time. The "pulse" mode for traffic recognition is the > major use. > > My ignorant guess is that halogen bulbs do not like to be pulsed or ramped > up too quickly during pulse mode. If the rapid power ramp up is the > primary cause, I am wondering if an appropriate choke (induction) would > slow that ramping down and return normal life to these devices. > > If I were to do a WAG . . . I'm guessing that you're > getting repetitive stress cracks in the filaments. > These things operate somewhat hotter than their older > cousins . . . most seem to have heavier filaments too. > > There are two things that erode filament integrity . . . > evaporation (total operating hours issue) and stress > cracks (combination of vibration and temperature cycling). > I'm wondering if the halogens are not more highly stressed > during each illumination cycle. Since a wig-wag operates > on the order of 2 flashes per second, 10 hours of flashing > would offer 72,000 or so temperature cycles. Far more cycles > than would be expected in automotive applications. Just > assuming 200 cycles per day in a high-beam lamp for night > highway driving would take 360 straight days of such service > to equal 10 hours of wig-wag. > > Any insight, suggestions into the failure mode and how to work around it > would be greatly appreciated. > > Not sure 'current ramping' would have a very useful effect. > Some of you may recall an experiment we did some years back > to evaluate the usefulness of inrush-limiters in wig-wagged > landing lights. Remember this plot? > > http://www.aeroelectric.com/Pictures/Curves/Wig_Wag_Currents.jpg > > We discovered that the lamp temperature stays pretty warm > during a 250 mS off-cycle such that you don't see the typical > cold-filament inrush each time the lamp is powered up. But > the temperature excursions between no-visible light and full > intensity is still significant. It may well be that the very > thing that makes the halogen a stellar illuminator amongst > incandescent lamps is it's Achilles Heel as well. > > Just a guess . . . but until I hear/get a better idea, I'm > sticking with it. > > Bob . . . > > > ________________________________ Message 13 ____________________________________ Time: 05:54:35 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Bruce, ...also a good suggestion, but, like HID's they are quite expensive when one needs a really bright recognition lamp. I plan to keep watching the LED market and see what comes in cost reduction.... Thanks, David ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ----- Original Message ----- From: "Bruce" Sent: Friday, September 09, 2011 3:44 PM Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > OK, how about LED? > > Bruce > WWW.Glasair.org > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of David > Lloyd > Sent: Friday, September 09, 2011 4:49 PM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > > > Good suggestion...all except for the considerable cost for dual > sets..... > David > > ____________________________________________________ > ----- Original Message ----- > From: "Bruce" > To: > Sent: Friday, September 09, 2011 11:16 AM > Subject: RE: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > >> >> Switch to HID. >> >> Bruce >> WWW.Glasair.org >> >> -----Original Message----- >> From: owner-aeroelectric-list-server@matronics.com >> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > David >> Lloyd >> Sent: Friday, September 09, 2011 1:31 PM >> To: aeroelectric-list@matronics.com >> Subject: AeroElectric-List: Halogen bulbs with wig wag >> circuitry....failure mode >> >> >> >> A general question for Bob and the List Members concerning halogen >> bulbs, >> i.e., GE H7604 landing light style. >> >> I am hoping someone on the List knows a lot about halogen bulb failure >> modes. >> >> I have H7604 lamps in my wing tips that aid landing and traffic >> recognition. >> They are controlled by a solid state switcher that is either >> OFF-ON-PULSED. >> ( I do not know the turn-on ramp characteristics..) >> >> They fail in less than 10 hrs of operation. Interesting both seem to >> fail >> nearly at the same time. The "pulse" mode for traffic recognition is >> the >> major use. >> >> My ignorant guess is that halogen bulbs do not like to be pulsed or >> ramped >> up too quickly during pulse mode. If the rapid power ramp up is the >> primary >> cause, I am wondering if an appropriate choke (induction) would slow >> that >> ramping down and return normal life to these devices. >> >> Any insight, suggestions into the failure mode and how to work around > it >> >> would be greatly appreciated. David >> >> >> >> >> >> >> >> > > > ________________________________ Message 14 ____________________________________ Time: 06:09:50 PM PST US From: Bill Watson Subject: AeroElectric-List: RF noise from Jeff's LED lights I am getting a loud hiss on both aircraft radios whenever my LED position lights are turned on. In fact, any FM radio in the vicinity gets the hiss too. I have "Jeff's LED lights for RVs" installed in the wing tips along with Bob Archer antennas. Though it may be worth noting that the SL30 Comm antenna is a standard belly mounted bent whip. I know the RF is coming from the radios because if I turn the volume down on the radios, the noise disappears (in other words, the intercom is not affected). The archives have some discussion of filters, resistors and capacitors but I'm not sure where to start. My first inclination is to disconnect one at a time to see if the noise is coming from both lights. Then I don't know where to start. Please help. Bill "falling in love with his first George" Watson ________________________________ Message 15 ____________________________________ Time: 07:22:34 PM PST US From: Bob McCallum Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode David; In automotive use halogen bulb life is adversely affected by low voltage, high resistance connections, poor grounds etc etc. "Dimming" a halogen bulb (at least certain types) is deadly for it. A bulb operated on low voltage will very rapidly darken as the filament material which evaporates is deposited on the quartz envelope and the lamp will rapidly fail as the filament cross section is reduced. I'm told, but don't quite understand why or how, that operating these bulbs at full or even slightly increased voltage somehow keeps the quartz hot enough that the filament material does not "plate out" or coat the inside of the envelope and instead migrates back to the filament keeping the filament intact and extending its life. That apparently is part of the purpose behind the halogen gas filling the envelope. I don't fully understand how this process works but anecdotally have proven it to be correct. I had a van with H4 halogen headlamps which used to "eat" bulbs. Couldn't keep bulbs in it for love nor money until I discovered that the voltage regulator was faulty and was barely keeping a charge in the battery. Upon replacing the regulator, thus getting the voltage back up to spec, the battery was noticeably healthier, starting was much quicker and easier, the lights were significantly brighter and they lasted for several years rather than the couple of months I'd been getting from them before. Your "pulsed" circuit may have the effect of appearing to be a reduced voltage source for the bulbs causing a similar situation to what I experienced first hand in my old van. Or this may be totally out to lunch and Bob's theory of heat cycling may be the answer, but because I've first hand knowledge of reduced voltage killing halogen bulbs I'll put the theory forward for whatever it's worth. Bob McC > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list- > server@matronics.com] On Behalf Of David Lloyd > Sent: Friday, September 09, 2011 1:31 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > > A general question for Bob and the List Members concerning halogen bulbs, > i.e., GE H7604 landing light style. > > I am hoping someone on the List knows a lot about halogen bulb failure > modes. > > I have H7604 lamps in my wing tips that aid landing and traffic recognition. > They are controlled by a solid state switcher that is either OFF-ON-PULSED. > ( I do not know the turn-on ramp characteristics..) > > They fail in less than 10 hrs of operation. Interesting both seem to fail > nearly at the same time. The "pulse" mode for traffic recognition is the > major use. > > My ignorant guess is that halogen bulbs do not like to be pulsed or ramped > up too quickly during pulse mode. If the rapid power ramp up is the primary > cause, I am wondering if an appropriate choke (induction) would slow that > ramping down and return normal life to these devices. > > Any insight, suggestions into the failure mode and how to work around it > would be greatly appreciated. David > > > _- > ==================================================== > ====== > _- > ==================================================== > ====== > _- > ==================================================== > ====== > _- > ==================================================== > ====== > > ________________________________ Message 16 ____________________________________ Time: 08:03:02 PM PST US From: "Vern Little" Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode I used inrush current limiters on my halogens (450+ hours so far). Since this also causes the lamps to take more time to reach full brightness, I modified the B&C flasher to slow it down by doubling the capacitance of the electrolytic capacitor inside the can. Double the resistor value would also work. V -----Original Message----- From: David Lloyd Sent: Friday, September 09, 2011 5:47 PM Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Bob, I think that you are totally correct concerning the thermo rapid cycle being the stress failure mode. When viewing the filaments with a mag. lens they look completely normal and intact until you look carefully at one end of the filament. They are broken at the very end. Odd that I have not run into others that are having the same problem as these bulbs are used in a lot of recognition applications. I suspect that if I left them ON continually, they would last a normal life. And, as you outline, in PULSE mode the thermo aspect is too much stress. I wonder now, if there is a heavy duty version of this bulb with bullet proof filament structure. I am installing new bulbs when delivered and will report back when I have a similar failure. Hopefully, I may have learned more. Thanks, David ___________________________________________________________________________ ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Friday, September 09, 2011 4:15 PM Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > > I have H7604 lamps in my wing tips that aid landing and traffic > recognition. They are controlled by a solid state switcher that is either > OFF-ON-PULSED. ( I do not know the turn-on ramp characteristics..) > > They fail in less than 10 hrs of operation. Interesting both seem to fail > nearly at the same time. The "pulse" mode for traffic recognition is the > major use. > > My ignorant guess is that halogen bulbs do not like to be pulsed or ramped > up too quickly during pulse mode. If the rapid power ramp up is the > primary cause, I am wondering if an appropriate choke (induction) would > slow that ramping down and return normal life to these devices. > > If I were to do a WAG . . . I'm guessing that you're > getting repetitive stress cracks in the filaments. > These things operate somewhat hotter than their older > cousins . . . most seem to have heavier filaments too. > > There are two things that erode filament integrity . . . > evaporation (total operating hours issue) and stress > cracks (combination of vibration and temperature cycling). > I'm wondering if the halogens are not more highly stressed > during each illumination cycle. Since a wig-wag operates > on the order of 2 flashes per second, 10 hours of flashing > would offer 72,000 or so temperature cycles. Far more cycles > than would be expected in automotive applications. Just > assuming 200 cycles per day in a high-beam lamp for night > highway driving would take 360 straight days of such service > to equal 10 hours of wig-wag. > > Any insight, suggestions into the failure mode and how to work around it > would be greatly appreciated. > > Not sure 'current ramping' would have a very useful effect. > Some of you may recall an experiment we did some years back > to evaluate the usefulness of inrush-limiters in wig-wagged > landing lights. Remember this plot? > > http://www.aeroelectric.com/Pictures/Curves/Wig_Wag_Currents.jpg > > We discovered that the lamp temperature stays pretty warm > during a 250 mS off-cycle such that you don't see the typical > cold-filament inrush each time the lamp is powered up. But > the temperature excursions between no-visible light and full > intensity is still significant. It may well be that the very > thing that makes the halogen a stellar illuminator amongst > incandescent lamps is it's Achilles Heel as well. > > Just a guess . . . but until I hear/get a better idea, I'm > sticking with it. > > Bob . . . > > ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 17 ____________________________________ Time: 09:10:36 PM PST US From: "Paul Zimmer" Subject: AeroElectric-List: Low Cost WigWag Alternatives Bob, of the alternatives presented in your article 'Low Cost Wigwag Alternatives', which would be most appropriate for a HID Taxi and Landing Light implementation, given that the HID lights need to be warmed up prior to flashing (assuming a manual warmup perior prior to switching to flashing)? Also being unfamiliar with the B&C WigWag, do both switches need to be in the wigwag position in order for wigwag to work, or is it an either or situation?. I'm referring to the to switch drawing on P.5 of the article. ________________________________ Message 18 ____________________________________ Time: 09:24:01 PM PST US From: "B Tomm" Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode I bought a 55W HID kit on Ebay for $55 + shipping ($70 total) as other have. Most HID's are 35 watt. I'm expecting these to be about twice as bright as 100watt incandescent, but haven't powered them up yet. I don't consider this to be an expensive upgrade. Bevan -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of David Lloyd Sent: Friday, September 09, 2011 5:51 PM Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode --> Bruce, ...also a good suggestion, but, like HID's they are quite expensive when one needs a really bright recognition lamp. I plan to keep watching the LED market and see what comes in cost reduction.... Thanks, David ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ ----- Original Message ----- From: "Bruce" Sent: Friday, September 09, 2011 3:44 PM Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > OK, how about LED? > > Bruce > WWW.Glasair.org > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > David Lloyd > Sent: Friday, September 09, 2011 4:49 PM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > > > Good suggestion...all except for the considerable cost for dual > sets..... > David > > ____________________________________________________ > ----- Original Message ----- > From: "Bruce" > To: > Sent: Friday, September 09, 2011 11:16 AM > Subject: RE: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > >> >> Switch to HID. >> >> Bruce >> WWW.Glasair.org >> >> -----Original Message----- >> From: owner-aeroelectric-list-server@matronics.com >> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > David >> Lloyd >> Sent: Friday, September 09, 2011 1:31 PM >> To: aeroelectric-list@matronics.com >> Subject: AeroElectric-List: Halogen bulbs with wig wag >> circuitry....failure mode >> >> >> >> A general question for Bob and the List Members concerning halogen >> bulbs, i.e., GE H7604 landing light style. >> >> I am hoping someone on the List knows a lot about halogen bulb >> failure modes. >> >> I have H7604 lamps in my wing tips that aid landing and traffic >> recognition. >> They are controlled by a solid state switcher that is either >> OFF-ON-PULSED. >> ( I do not know the turn-on ramp characteristics..) >> >> They fail in less than 10 hrs of operation. Interesting both seem to >> fail nearly at the same time. The "pulse" mode for traffic >> recognition is the major use. >> >> My ignorant guess is that halogen bulbs do not like to be pulsed or >> ramped up too quickly during pulse mode. If the rapid power ramp up >> is the primary cause, I am wondering if an appropriate choke >> (induction) would slow that ramping down and return normal life to >> these devices. >> >> Any insight, suggestions into the failure mode and how to work around > it >> >> would be greatly appreciated. David >> >> >> >> >> >> >> >> > > > ________________________________ Message 19 ____________________________________ Time: 10:41:22 PM PST US From: jerb Subject: Re: AeroElectric-List: AeroLed landing lights not working with wig wag relay Check out the Show Me units - Their a Wig-Wag flasher unit like used on emergency vehicles like police cars. I have one of these on my plane which drives a pair of driving lights for the purpose of recognition lights and it works good. The unit I have allows you to select flash both, alternate flash, or both lights on. Also check the wattage of your landing lights and what a unit can handle. They can be purchased with wire pig tails or screw terminals, I got the one with screw terminals. Also there is flash rate, I got the slowest I could get which comes out to be a second on, a second off. I think mine cost me around $45 dollars a few years back - I use it for switching recognition (driving) lights on my ultralight. http://shop.store.yahoo.com/bcssales/shomranheadf.html Do a search on Google.com for Able 2 & Show ME wig wag flashers. There is a lot of price variation between places that sell them, I got mine from the manufacturer - they had the best price. The problem you may be experiencing with the LED lights is the low current load if the unit using a thermo-switch much like a turn-signal flash unit. I don't think you would have a problem with the unit above. I now had the units and the driving lights running for over 10 years. My how time flys . . . . jerb At 08:13 AM 9/9/2011, you wrote: > > >At 07:56 AM 9/9/2011, you wrote: >> >> >>I purchased the B&C wig wag relay and wired it according to the >>schematic for an off-on-on switch and B&C diode assembly. The >>wig-wag is in the middle position. I included the >>resistors between the relay and ground shown in the updated >>schematic. The system works fine with incandecent nav lights but >>not with the LED landing lights. Only one LED light turns on in wig >>wag mode and both lights turn on in continuous on mode. The nav >>lights draw about 3.2 amps, the LED lights about 3.7 amp. Anyone >>know what is going on here and how to fix it. Should I just >>purchase an electronic wig wag unit designed for LED's? > > I modified that drawing for B&C based on testing I > did using one of the flashers from their inventory. > The resistors were added to emulate the fixed load > offered by incandescent lamps. You are the second > individual who was unable to duplicate the behavior > I was getting on the bench. I have a pair of Whelen > LED landing lights loaned to me by another reader > and I plotted their current draw vs. voltage curve > which I posted on the List a few days ago. > > I'm somewhat tied up with some family matters and > can't get back to the bench right now to figure out > what's going on . . . but the solution will not > be difficult. Sit tight for the moment . . . watch > this space. > > > Bob . . . ________________________________ Message 20 ____________________________________ Time: 10:58:20 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Bevan, I think that I have viewed some of those on eBay. But, I came away with the idea that they were not a complete kit; power supply, harness, bulb/lamp combo, etc. I will take a better review of the offerings. Please let me know if you receive a complete operational system. David =============================================================== ----- Original Message ----- From: "B Tomm" Sent: Friday, September 09, 2011 9:20 PM Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > I bought a 55W HID kit on Ebay for $55 + shipping ($70 total) as other > have. > Most HID's are 35 watt. I'm expecting these to be about twice as bright > as > 100watt incandescent, but haven't powered them up yet. I don't consider > this to be an expensive upgrade. > > Bevan > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of David > Lloyd > Sent: Friday, September 09, 2011 5:51 PM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > --> > > Bruce, > ...also a good suggestion, but, like HID's they are quite expensive when > one > needs a really bright recognition lamp. > I plan to keep watching the LED market and see what comes in cost > reduction.... Thanks, David > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > ----- Original Message ----- > From: "Bruce" > To: > Sent: Friday, September 09, 2011 3:44 PM > Subject: RE: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > >> >> OK, how about LED? >> >> Bruce >> WWW.Glasair.org >> >> -----Original Message----- >> From: owner-aeroelectric-list-server@matronics.com >> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of >> David Lloyd >> Sent: Friday, September 09, 2011 4:49 PM >> To: aeroelectric-list@matronics.com >> Subject: Re: AeroElectric-List: Halogen bulbs with wig wag >> circuitry....failure mode >> >> >> >> Good suggestion...all except for the considerable cost for dual >> sets..... >> David >> >> ____________________________________________________ >> ----- Original Message ----- >> From: "Bruce" >> To: >> Sent: Friday, September 09, 2011 11:16 AM >> Subject: RE: AeroElectric-List: Halogen bulbs with wig wag >> circuitry....failure mode >> >> >>> >>> Switch to HID. >>> >>> Bruce >>> WWW.Glasair.org >>> >>> -----Original Message----- >>> From: owner-aeroelectric-list-server@matronics.com >>> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of >> David >>> Lloyd >>> Sent: Friday, September 09, 2011 1:31 PM >>> To: aeroelectric-list@matronics.com >>> Subject: AeroElectric-List: Halogen bulbs with wig wag >>> circuitry....failure mode >>> >>> >>> >>> A general question for Bob and the List Members concerning halogen >>> bulbs, i.e., GE H7604 landing light style. >>> >>> I am hoping someone on the List knows a lot about halogen bulb >>> failure modes. >>> >>> I have H7604 lamps in my wing tips that aid landing and traffic >>> recognition. >>> They are controlled by a solid state switcher that is either >>> OFF-ON-PULSED. >>> ( I do not know the turn-on ramp characteristics..) >>> >>> They fail in less than 10 hrs of operation. Interesting both seem to >>> fail nearly at the same time. The "pulse" mode for traffic >>> recognition is the major use. >>> >>> My ignorant guess is that halogen bulbs do not like to be pulsed or >>> ramped up too quickly during pulse mode. If the rapid power ramp up >>> is the primary cause, I am wondering if an appropriate choke >>> (induction) would slow that ramping down and return normal life to >>> these devices. >>> >>> Any insight, suggestions into the failure mode and how to work around >> it >>> >>> would be greatly appreciated. David >>> >>> >>> >>> >>> >>> >>> >>> >> >> >> >> >> >> >> >> > > > ________________________________ Message 21 ____________________________________ Time: 11:02:50 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Vern, I am unfamiliar with the "current limiters" that you mention. Your solution looks great. Please give a bit more detail... I will check for my solid state flasher model and if it can be modified...(not potted, etc.) It was part of the RMD wing tip system. David =========================================================== ----- Original Message ----- From: "Vern Little" Sent: Friday, September 09, 2011 7:57 PM Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > > I used inrush current limiters on my halogens (450+ hours so far). Since > this also causes the lamps to take more time to reach full brightness, I > modified the B&C flasher to slow it down by doubling the capacitance of > the electrolytic capacitor inside the can. Double the resistor value > would also work. > > V > > > -----Original Message----- > From: David Lloyd > Sent: Friday, September 09, 2011 5:47 PM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > > > Bob, > I think that you are totally correct concerning the thermo rapid cycle > being > the stress failure mode. > > When viewing the filaments with a mag. lens they look completely normal > and > intact until you look carefully at one end of the filament. They are > broken > at the very end. > > Odd that I have not run into others that are having the same problem as > these bulbs are used in a lot of recognition applications. > > I suspect that if I left them ON continually, they would last a normal > life. > And, as you outline, in PULSE mode the thermo aspect is too much stress. > I > wonder now, if there is a heavy duty version of this bulb with bullet > proof > filament structure. > > I am installing new bulbs when delivered and will report back when I have > a > similar failure. Hopefully, I may have learned more. > Thanks, David > > ___________________________________________________________________________ > > ----- Original Message ----- > From: "Robert L. Nuckolls, III" > To: > Sent: Friday, September 09, 2011 4:15 PM > Subject: Re: AeroElectric-List: Halogen bulbs with wig wag > circuitry....failure mode > > >> >> >> I have H7604 lamps in my wing tips that aid landing and traffic >> recognition. They are controlled by a solid state switcher that is either >> OFF-ON-PULSED. ( I do not know the turn-on ramp characteristics..) >> >> They fail in less than 10 hrs of operation. Interesting both seem to >> fail nearly at the same time. The "pulse" mode for traffic recognition >> is the major use. >> >> My ignorant guess is that halogen bulbs do not like to be pulsed or >> ramped up too quickly during pulse mode. If the rapid power ramp up is >> the primary cause, I am wondering if an appropriate choke (induction) >> would slow that ramping down and return normal life to these devices. >> >> If I were to do a WAG . . . I'm guessing that you're >> getting repetitive stress cracks in the filaments. >> These things operate somewhat hotter than their older >> cousins . . . most seem to have heavier filaments too. >> >> There are two things that erode filament integrity . . . >> evaporation (total operating hours issue) and stress >> cracks (combination of vibration and temperature cycling). >> I'm wondering if the halogens are not more highly stressed >> during each illumination cycle. Since a wig-wag operates >> on the order of 2 flashes per second, 10 hours of flashing >> would offer 72,000 or so temperature cycles. Far more cycles >> than would be expected in automotive applications. Just >> assuming 200 cycles per day in a high-beam lamp for night >> highway driving would take 360 straight days of such service >> to equal 10 hours of wig-wag. >> >> Any insight, suggestions into the failure mode and how to work around it >> would be greatly appreciated. >> >> Not sure 'current ramping' would have a very useful effect. >> Some of you may recall an experiment we did some years back >> to evaluate the usefulness of inrush-limiters in wig-wagged >> landing lights. Remember this plot? >> >> http://www.aeroelectric.com/Pictures/Curves/Wig_Wag_Currents.jpg >> >> We discovered that the lamp temperature stays pretty warm >> during a 250 mS off-cycle such that you don't see the typical >> cold-filament inrush each time the lamp is powered up. But >> the temperature excursions between no-visible light and full >> intensity is still significant. It may well be that the very >> thing that makes the halogen a stellar illuminator amongst >> incandescent lamps is it's Achilles Heel as well. >> >> Just a guess . . . but until I hear/get a better idea, I'm >> sticking with it. >> >> Bob . . . >> >> >> >> >> > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > > > ________________________________ Message 22 ____________________________________ Time: 11:05:59 PM PST US From: "David Lloyd" Subject: Re: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode Thanks Bob for giving me other possible answers. When I carefully looked at the halogen bulb inside the lamp, they did not appear to have any darkness that I could see. Appeared crystal clear. I will look again... David =================== ----- Original Message ----- From: Bob McCallum To: aeroelectric-list@matronics.com Sent: Friday, September 09, 2011 7:16 PM Subject: RE: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode David; In automotive use halogen bulb life is adversely affected by low voltage, high resistance connections, poor grounds etc etc. "Dimming" a halogen bulb (at least certain types) is deadly for it. A bulb operated on low voltage will very rapidly darken as the filament material which evaporates is deposited on the quartz envelope and the lamp will rapidly fail as the filament cross section is reduced. I'm told, but don't quite understand why or how, that operating these bulbs at full or even slightly increased voltage somehow keeps the quartz hot enough that the filament material does not "plate out" or coat the inside of the envelope and instead migrates back to the filament keeping the filament intact and extending its life. That apparently is part of the purpose behind the halogen gas filling the envelope. I don't fully understand how this process works but anecdotally have proven it to be correct. I had a van with H4 halogen headlamps which used to "eat" bulbs. Couldn't keep bulbs in it for love nor money until I discovered that the voltage regulator was faulty and was barely keeping a charge in the battery. Upon replacing the regulator, thus getting the voltage back up to spec, the battery was noticeably healthier, starting was much quicker and easier, the lights were significantly brighter and they lasted for several years rather than the couple of months I'd been getting from them before. Your "pulsed" circuit may have the effect of appearing to be a reduced voltage source for the bulbs causing a similar situation to what I experienced first hand in my old van. Or this may be totally out to lunch and Bob's theory of heat cycling may be the answer, but because I've first hand knowledge of reduced voltage killing halogen bulbs I'll put the theory forward for whatever it's worth. Bob McC > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list- > server@matronics.com] On Behalf Of David Lloyd > Sent: Friday, September 09, 2011 1:31 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: Halogen bulbs with wig wag circuitry....failure mode > > > A general question for Bob and the List Members concerning halogen bulbs, > i.e., GE H7604 landing light style. > > I am hoping someone on the List knows a lot about halogen bulb failure > modes. > > I have H7604 lamps in my wing tips that aid landing and traffic recognition. > They are controlled by a solid state switcher that is either OFF-ON-PULSED. > ( I do not know the turn-on ramp characteristics..) > > They fail in less than 10 hrs of operation. Interesting both seem to fail > nearly at the same time. The "pulse" mode for traffic recognition is the > major use. > > My ignorant guess is that halogen bulbs do not like to be pulsed or ramped > up too quickly during pulse mode. If the rapid power ramp up is the primary > cause, I am wondering if an appropriate choke (induction) would slow that > ramping down and return normal life to these devices. > > Any insight, suggestions into the failure mode and how to work around it > would be greatly appreciated. David > > > _- > == > ====== > style='mso-spacerun:yes'> - The AeroElectric-List Email Forum - > > style='mso-spacerun:yes'> --> http://www.matronics.com/Navigator?AeroElectric-List > > _- > == > ====== > style='mso-spacerun:yes'> - MATRONICS WEB FORUMS - > > style='mso-spacerun:yes'> --> http://forums.matronics.com > > _- > == > ====== > style='mso-spacerun:yes'> - List Contribution Web Site - > style='mso-spacerun:yes'> Thank you for your generous support! > style='mso-spacerun:yes'> -Matt Dralle, List Admin. > style='mso-spacerun:yes'> --> 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.