---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 03/24/05: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:40 AM - EGT interference (drshufly@aol.com) 2. 07:40 AM - Diodes for Master and Strater relays (Joe & Jan Connell) 3. 07:43 AM - Re: Re: led dimmer question (D Wysong) 4. 08:08 AM - Re: led dimmer question (Eric M. Jones) 5. 01:35 PM - Re: Diodes across relay coils (Eric M. Jones) 6. 02:43 PM - Re: Re: Diodes across relay coils (Matt Prather) 7. 03:00 PM - Re: Diodes across relay coils (rd2@evenlink.com) 8. 03:11 PM - Re: Re: Diodes across relay coils (Richard Tasker) 9. 03:12 PM - Re: Re: Diodes across relay coils (paul wilson) 10. 04:00 PM - Re: Re: Diodes across relay coils (Richard Tasker) 11. 04:31 PM - Re: Re: Diodes across relay coils (paul wilson) 12. 04:31 PM - Re: Diodes across relay coils (Eric M. Jones) ________________________________ Message 1 _____________________________________ Time: 05:40:50 AM PST US From: drshufly@aol.com Subject: AeroElectric-List: EGT interference --> AeroElectric-List message posted by: drshufly@aol.com My Glasair EGT/CHT readings (as read on my RMI Micromonitor) are steady until I energize the Whelan strobe system and then they jump around several hundred degrees. I'm wondering if a Radio Shack noise filter on the strobe power supply might correct this situation. Closest point of approach for any mutual wire is twelve inches; strobes are the instigator; EGT/CHT is the victim so I wonder if a filter would do any good. Could the problem be simply RFI coming from the strobes? Would appreciate comments. Bob Shumaker in Virginia Glasair IIS-RG with 600 safe hours ________________________________ Message 2 _____________________________________ Time: 07:40:38 AM PST US From: "Joe & Jan Connell" Subject: AeroElectric-List: Diodes for Master and Strater relays --> AeroElectric-List message posted by: "Joe & Jan Connell" Hi Guys, I've been searching the AeroElectric-List and the RV-list to get information on which diode to use across these relays. Can you provide me a diode part number and ratings? I'd rather not buy the prepackaged solution from Van's... Thanks. Joe Connell Stewartville, MN RV-9A N95JJ wiring ________________________________ Message 3 _____________________________________ Time: 07:43:54 AM PST US From: D Wysong Subject: Re: AeroElectric-List: Re: led dimmer question --> AeroElectric-List message posted by: D Wysong Hello Skip - > That is, the 12v+ from the gps box would go to the led, the negative leg of > the various leds would be connected in common to the input of the LM 137, and > the output of the LM 137 would be grounded. Sort of a LM 317 setup but on > the "downside" leg of the leds. The LM137 expects a negative voltage differential between the Vin and ground. Maybe if you attach the LED to the -Vout terminal, your ground to the -Vin terminal, and a positive supply voltage to the Ground terminal it'll work. Seems upside down and backwards... but samples are cheap! Give it a try! :-) There's an application circuit in the LM117/LM317 datasheet for "Digitally Selected Outputs" that will work with a few mod's (more parts!). If you put your LEDs inline with those transistors and move the entire transistor bank from the Adj rail to the Vout rail, you can attach your annunciator outputs to the transistor Inputs and drive your parallel-dimmed LEDs that way. D ________________________________ Message 4 _____________________________________ Time: 08:08:36 AM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: led dimmer question --> AeroElectric-List message posted by: "Eric M. Jones" --> AeroElectric-List message posted by: CardinalNSB@aol.com >I have been playing with the LM 317 adjustable voltage regulator > 12 volt positive input to the LM 317 >led positive lead(s) all connected to the output of the LM 317 >common ground for led leads to battery negative >The brightness of the light is based on the (adjusted) voltage, whether 1 or >more leds are connected. So, this will dim leds, brightness is stable, >whether 1 or more leds are in the system. >However, my Garmin 300xl outputs 12 volt + per annnciator light so the LM >317 isn't appropriate. I would need a separate LM 317 for each light circuit >and a way to control each LM 317 at the same time. >Is there a similar product that the common ground from the leds would be the >input and the chassis ground would be the output that would maintain the >reduced voltage? Is this what the LM 137 does? >That is, the 12v+ from the gps box would go to the led, the negative leg of >the various leds would be connected in common to the input of the LM 137, and >the output of the LM 137 would be grounded. Sort of a LM 317 setup but on >the "downside" leg of the leds. Thanks for the help. Skip Simpson. Skip, It certainly seems reasonable to use a negative regulator in this application. After all the electrons don't know the difference. But when you look at the "negative" LM317, the LM137 you find that all is not so simple. Whereas the LM317 has a positive voltage in and a regulated positive voltage out, the LM137 would have a ground in and a "regulated" ground out. a regulated ground is still zero. Negative voltages are arranged at the power source by grounding the positive lead of one battery to the negative lead of the other. Then one battery provides positive, the connection between the batteries is "ground" and the second battery negative ground terminal becomes "negative". Negative voltages can also be had by a little IC power supply. You don't need to consider them--or the negative voltage regulator. Assuming the Garmin output can't be dimmed (and I'd surely check into this with Garmin!) then consider controlling the current through the LEDs by using an NPN transistor with a grounded emitter. Consider using a National Semiconductor LM395 (can't break it). Group all your LED cathode grounds together and change the current through the base. Lot's of help online for the circuit. Don't be afraid. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net "Then I got married. I thought...well, I figured that...ahhh. Hell, I don't know WHAT I was thinking...." --My friend Victor ________________________________ Message 5 _____________________________________ Time: 01:35:39 PM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: Diodes across relay coils --> AeroElectric-List message posted by: "Eric M. Jones" --> AeroElectric-List message posted by: "Paul Messinger" >For decades 99.999% of the engineering world recommended and used the common rectifier diode across inductors like relay coils to suppress the inductive spike that happens hen the power to the inductor is interrupted. Hey, my dad taught me this technique....And he claimed never to be wrong. Usually. >I have removed all the simple diodes across relays and replaced them with by directional transorbs and also supplied parts to the local builders as well. >Paul This posting was really significant but has not been much commented on. Basically, ALL the suppressor diodes on all coils and relays and contactors should be changed to bi-directional transorbs or similar. Okay don't panic, but put it on your list. If you are having problems (sticking contactors?, better upgrade now). This is a significant change we can all blame Paul Messinger for. Read these links-- Yikes.... http://relays.tycoelectronics.com/application.asp http://relays.tycoelectronics.com/kilovac/appnotes/transients.stm And of course, these are available from me. http://www.periheliondesign.com/suppressors/SnapJack.pdf Website hasn't been updated yet. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net "...as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns - the ones we don't know we don't know." D. Rumsfeld ________________________________ Message 6 _____________________________________ Time: 02:43:59 PM PST US Subject: Re: AeroElectric-List: Re: Diodes across relay coils From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Reading both of these messages, it might sound like using a flyback diode is worse than nothing. Is that the point? Or is it that flyback diodes only fix one kind of problem (arcing from the collapsing field caused by the high dI/dt), but might make a different one worse (somewhat increase contact bounce by slowing/reversing armature motion)? Does anyone have data to quantify how much longer the contacts will live with no protection, vs. diode protection, vs. transorbs? That would be useful. Regards, Matt- VE N34RD, C150 N714BK > --> AeroElectric-List message posted by: "Eric M. Jones" > > > --> AeroElectric-List message posted by: "Paul Messinger" > > >>For decades 99.999% of the engineering world recommended and used the > common rectifier diode across inductors like relay coils to suppress the > inductive spike that happens hen the power to the inductor is > interrupted. > > Hey, my dad taught me this technique....And he claimed never to be > wrong. Usually. > >>I have removed all the simple diodes across relays and replaced them >> with > by directional transorbs and also supplied parts to the local builders > as well. >>Paul > > This posting was really significant but has not been much commented on. > Basically, ALL the suppressor diodes on all coils and relays and > contactors should be changed to bi-directional transorbs or similar. > Okay don't panic, but put it on your list. If you are having problems > (sticking contactors?, better upgrade now). This is a significant change > we can all blame Paul Messinger for. > > Read these links-- Yikes.... > > http://relays.tycoelectronics.com/application.asp > > http://relays.tycoelectronics.com/kilovac/appnotes/transients.stm > > And of course, these are available from me. > > http://www.periheliondesign.com/suppressors/SnapJack.pdf Website > hasn't been updated yet. > > Regards, > Eric M. Jones > www.PerihelionDesign.com > 113 Brentwood Drive > Southbridge MA 01550-2705 > Phone (508) 764-2072 > Email: emjones@charter.net > > "...as we know, there are known knowns; there are things we know we > know. We also know there are known unknowns; that is to say we know > there are some things we do not know. But there are also unknown > unknowns - the ones we don't know we don't know." D. Rumsfeld > > ________________________________ Message 7 _____________________________________ Time: 03:00:25 PM PST US From: rd2@evenlink.com Subject: Re: AeroElectric-List: Diodes across relay coils --> AeroElectric-List message posted by: rd2@evenlink.com Eric, thanks for not letting this escape and sink in mailbaskets, be forgotten, deleted whatever. Paul, thanks. I am no engineer but have learned a lot through my hobby, and this list, and Bob et all. The by-directional transorbs had caught my attention but the subject had started to fade in the daily streams of incoming info. This brought it back. Thank you list. Rumen _____________________Original message __________________________ (received from Eric M. Jones; Date: 04:15 PM 3/24/2005 -0500) --> AeroElectric-List message posted by: "Eric M. Jones" --> AeroElectric-List message posted by: "Paul Messinger" >For decades 99.999% of the engineering world recommended and used the common rectifier diode across inductors like relay coils to suppress the inductive spike that happens hen the power to the inductor is interrupted. Hey, my dad taught me this technique....And he claimed never to be wrong. Usually. >I have removed all the simple diodes across relays and replaced them with by directional transorbs and also supplied parts to the local builders as well. >Paul This posting was really significant but has not been much commented on. Basically, ALL the suppressor diodes on all coils and relays and contactors should be changed to bi-directional transorbs or similar. Okay don't panic, but put it on your list. If you are having problems (sticking contactors?, better upgrade now). This is a significant change we can all blame Paul Messinger for. Read these links-- Yikes.... http://relays.tycoelectronics.com/application.asp http://relays.tycoelectronics.com/kilovac/appnotes/transients.stm And of course, these are available from me. http://www.periheliondesign.com/suppressors/SnapJack.pdf Website hasn't been updated yet. Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net "...as we know, there are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns - the ones we don't know we don't know." D. Rumsfeld ________________________________ Message 8 _____________________________________ Time: 03:11:28 PM PST US From: Richard Tasker Subject: Re: AeroElectric-List: Re: Diodes across relay coils --> AeroElectric-List message posted by: Richard Tasker Diodes are much better than nothing, but they fix one problem and make another worse. Depending on your whole system one or the other could be worse. Are large negative voltage spikes every time you shut the relay off worse than the possibility of the relay welding on at some time? I suspect that, for most of us, the slight potential of welded contacts are better than spikes. With the transorbs you sort of have the best of both worlds - you limit the spike to something more reasonable (whatever the voltage rating of the transorb is) and you minimize the likelihood of welded contacts due to the much faster turnoff time. Unfortunately, it is impossible to meaningfully quantify the difference in contact life without knowing a whole lot about your specific application. Dick Tasker Matt Prather wrote: >--> AeroElectric-List message posted by: "Matt Prather" > >Reading both of these messages, it might sound like using a flyback >diode is worse than nothing. Is that the point? Or is it that flyback >diodes >only fix one kind of problem (arcing from the collapsing field caused by >the high dI/dt), but might make a different one worse (somewhat increase >contact bounce by slowing/reversing armature motion)? > >Does anyone have data to quantify how much longer the contacts will live >with no protection, vs. diode protection, vs. transorbs? That would be >useful. > > >Regards, > >Matt- >VE N34RD, C150 N714BK > > > > >>--> AeroElectric-List message posted by: "Eric M. Jones" >> >> >>--> AeroElectric-List message posted by: "Paul Messinger" >> >> >> >> >>>For decades 99.999% of the engineering world recommended and used the >>> >>> >>common rectifier diode across inductors like relay coils to suppress the >>inductive spike that happens hen the power to the inductor is >>interrupted. >> >>Hey, my dad taught me this technique....And he claimed never to be >>wrong. Usually. >> >> >> >>>I have removed all the simple diodes across relays and replaced them >>>with >>> >>> >>by directional transorbs and also supplied parts to the local builders >>as well. >> >> >>>Paul >>> >>> >>This posting was really significant but has not been much commented on. >>Basically, ALL the suppressor diodes on all coils and relays and >>contactors should be changed to bi-directional transorbs or similar. >>Okay don't panic, but put it on your list. If you are having problems >>(sticking contactors?, better upgrade now). This is a significant change >>we can all blame Paul Messinger for. >> >>Read these links-- Yikes.... >> >>http://relays.tycoelectronics.com/application.asp >> >>http://relays.tycoelectronics.com/kilovac/appnotes/transients.stm >> >>And of course, these are available from me. >> >>http://www.periheliondesign.com/suppressors/SnapJack.pdf Website >>hasn't been updated yet. >> >>Regards, >>Eric M. Jones >>www.PerihelionDesign.com >>113 Brentwood Drive >>Southbridge MA 01550-2705 >>Phone (508) 764-2072 >>Email: emjones@charter.net >> >>"...as we know, there are known knowns; there are things we know we >>know. We also know there are known unknowns; that is to say we know >>there are some things we do not know. But there are also unknown >>unknowns - the ones we don't know we don't know." D. Rumsfeld >> ________________________________ Message 9 _____________________________________ Time: 03:12:30 PM PST US From: paul wilson Subject: Re: AeroElectric-List: Re: Diodes across relay coils --> AeroElectric-List message posted by: paul wilson Eric, Paul said "directional transorbs" You said "bi-directional transorbs or similar" Typo? Or do I need help to understand? Thanks, Paul ====================== At 04:15 PM 3/24/05 -0500, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >--> AeroElectric-List message posted by: "Paul Messinger" > > >For decades 99.999% of the engineering world recommended and used the >common rectifier diode across inductors like relay coils to suppress the >inductive spike that happens hen the power to the inductor is interrupted. > >Hey, my dad taught me this technique....And he claimed never to be wrong. >Usually. > > >I have removed all the simple diodes across relays and replaced them with >by directional transorbs and also supplied parts to the local builders as >well. > >Paul > >This posting was really significant but has not been much commented on. >Basically, ALL the suppressor diodes on all coils and relays and contactors >should be changed to bi-directional transorbs or similar. Okay don't panic, >but put it on your list. If you are having problems (sticking contactors?, >better upgrade now). This is a significant change we can all blame Paul >Messinger for. > >Read these links-- Yikes.... > >http://relays.tycoelectronics.com/application.asp > >http://relays.tycoelectronics.com/kilovac/appnotes/transients.stm > >And of course, these are available from me. > >http://www.periheliondesign.com/suppressors/SnapJack.pdf Website hasn't >been updated yet. > >Regards, >Eric M. Jones >www.PerihelionDesign.com >113 Brentwood Drive >Southbridge MA 01550-2705 >Phone (508) 764-2072 >Email: emjones@charter.net > >"...as we know, there are known knowns; there are things we know we know. >We also know there are known unknowns; that is to say we know there are >some things we do not know. But there are also unknown unknowns - the ones >we don't know we don't know." D. Rumsfeld ________________________________ Message 10 ____________________________________ Time: 04:00:45 PM PST US From: Richard Tasker Subject: Re: AeroElectric-List: Re: Diodes across relay coils --> AeroElectric-List message posted by: Richard Tasker Actually Paul did say bidirectional transorb. He also mentioned if you use a uni-directional transorb you must also use a series diode with it. A bi-directional transorb must have a sufficiently high breakdown voltage so it never turns on with normal battery/alternator voltage present - i.e. use one with at least a 16V breakdown. As an exercise for the student, you can "tune" the response by using a lower voltage transorb with a series diode to get whatever voltage spike you are comfortable with. I.e., trade off turn-off time with voltage spike magnitude. :-) Or not... Dick Tasker paul wilson wrote: >--> AeroElectric-List message posted by: paul wilson > >Eric, > Paul said "directional transorbs" > You said "bi-directional transorbs or similar" > Typo? Or do I need help to understand? >Thanks, Paul >====================== > >At 04:15 PM 3/24/05 -0500, you wrote: > > >>--> AeroElectric-List message posted by: "Eric M. Jones" >> >>--> AeroElectric-List message posted by: "Paul Messinger" >> >> >> >>>For decades 99.999% of the engineering world recommended and used the >>> >>> >>common rectifier diode across inductors like relay coils to suppress the >>inductive spike that happens hen the power to the inductor is interrupted. >> >>Hey, my dad taught me this technique....And he claimed never to be wrong. >>Usually. >> >> >> >>>I have removed all the simple diodes across relays and replaced them with >>> >>> >>by directional transorbs and also supplied parts to the local builders as >>well. >> >> >>>Paul >>> >>> >>This posting was really significant but has not been much commented on. >>Basically, ALL the suppressor diodes on all coils and relays and contactors >>should be changed to bi-directional transorbs or similar. Okay don't panic, >>but put it on your list. If you are having problems (sticking contactors?, >>better upgrade now). This is a significant change we can all blame Paul >>Messinger for. >> >>Read these links-- Yikes.... >> >>http://relays.tycoelectronics.com/application.asp >> >>http://relays.tycoelectronics.com/kilovac/appnotes/transients.stm >> >>And of course, these are available from me. >> >>http://www.periheliondesign.com/suppressors/SnapJack.pdf Website hasn't >>been updated yet. >> >>Regards, >>Eric M. Jones >>www.PerihelionDesign.com >>113 Brentwood Drive >>Southbridge MA 01550-2705 >>Phone (508) 764-2072 >>Email: emjones@charter.net >> >>"...as we know, there are known knowns; there are things we know we know. >>We also know there are known unknowns; that is to say we know there are >>some things we do not know. But there are also unknown unknowns - the ones >>we don't know we don't know." D. Rumsfeld >> > > ________________________________ Message 11 ____________________________________ Time: 04:31:12 PM PST US From: paul wilson Subject: Re: AeroElectric-List: Re: Diodes across relay coils --> AeroElectric-List message posted by: paul wilson Thanks Dick Most of the discussion went past me as you noted. I need the inputs to be pretty short and simple. :-) Paul W ========== At 06:58 PM 3/24/05 -0500, you wrote: >--> AeroElectric-List message posted by: Richard Tasker > > >Actually Paul did say bidirectional transorb. He also mentioned if you >use a uni-directional transorb you must also use a series diode with it. > >A bi-directional transorb must have a sufficiently high breakdown >voltage so it never turns on with normal battery/alternator voltage >present - i.e. use one with at least a 16V breakdown. > >As an exercise for the student, you can "tune" the response by using a >lower voltage transorb with a series diode to get whatever voltage spike >you are comfortable with. I.e., trade off turn-off time with voltage >spike magnitude. :-) Or not... > >Dick Tasker > > >paul wilson wrote: > > >--> AeroElectric-List message posted by: paul wilson > > > >Eric, > > Paul said "directional transorbs" > > You said "bi-directional transorbs or similar" > > Typo? Or do I need help to understand? > >Thanks, Paul > >====================== > > > >At 04:15 PM 3/24/05 -0500, you wrote: > > > > > >>--> AeroElectric-List message posted by: "Eric M. Jones" > > >> > >>--> AeroElectric-List message posted by: "Paul Messinger" > > >> > >> > >> > >>>For decades 99.999% of the engineering world recommended and used the > >>> > >>> > >>common rectifier diode across inductors like relay coils to suppress the > >>inductive spike that happens hen the power to the inductor is interrupted. > >> > >>Hey, my dad taught me this technique....And he claimed never to be wrong. > >>Usually. > >> > >> > >> > >>>I have removed all the simple diodes across relays and replaced them with > >>> > >>> > >>by directional transorbs and also supplied parts to the local builders as > >>well. > >> > >> > >>>Paul > >>> > >>> > >>This posting was really significant but has not been much commented on. > >>Basically, ALL the suppressor diodes on all coils and relays and contactors > >>should be changed to bi-directional transorbs or similar. Okay don't panic, > >>but put it on your list. If you are having problems (sticking contactors?, > >>better upgrade now). This is a significant change we can all blame Paul > >>Messinger for. > >> > >>Read these links-- Yikes.... > >> > >>http://relays.tycoelectronics.com/application.asp > >> > >>http://relays.tycoelectronics.com/kilovac/appnotes/transients.stm > >> > >>And of course, these are available from me. > >> > >>http://www.periheliondesign.com/suppressors/SnapJack.pdf Website hasn't > >>been updated yet. > >> > >>Regards, > >>Eric M. Jones > >>www.PerihelionDesign.com > >>113 Brentwood Drive > >>Southbridge MA 01550-2705 > >>Phone (508) 764-2072 > >>Email: emjones@charter.net > >> > >>"...as we know, there are known knowns; there are things we know we know. > >>We also know there are known unknowns; that is to say we know there are > >>some things we do not know. But there are also unknown unknowns - the ones > >>we don't know we don't know." D. Rumsfeld > >> > > > > > > ________________________________ Message 12 ____________________________________ Time: 04:31:12 PM PST US From: "Eric M. Jones" Subject: AeroElectric-List: Re: Diodes across relay coils --> AeroElectric-List message posted by: "Eric M. Jones" --> AeroElectric-List message posted by: paul wilson >Eric, > Paul said "directional transorbs" >You said "bi-directional transorbs or similar" >Typo? Or do I need help to understand? >Thanks, Paul ====================== Paul Messinger wrote > >I have removed all the simple diodes across relays and replaced them with >>by directional transorbs and also supplied parts to the local builders as >>well. > >Paul But hear Paul did not spel so gud. Bi-Directional...There is a class of these---Transorbs, Transils, Mosorbs, etc. all bi-directional Zener Transient Voltage Suppressor Diodes. "SnapJacks". Regards, Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive Southbridge MA 01550-2705 Phone (508) 764-2072 Email: emjones@charter.net "I tried being reasonable--I didn't like it!" --Clint Eastwood