---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 04/30/13: 13 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:08 AM - Re: Re: Questions for Bob after talking to B&C... (Robert L. Nuckolls, III) 2. 08:46 AM - Re: S704-1 Relay Question (nuckollsr) 3. 10:18 AM - Feedback Request on Push-to-talk circuit... (idleup) 4. 10:35 AM - Re: S704-1 Relay Question (idleup) 5. 10:37 AM - Re: Questions for Bob after talking to B&C... (idleup) 6. 12:45 PM - Re: Feedback Request on Push-to-talk circuit... (Vern Little) 7. 12:45 PM - Re: Re: S704-1 Relay Question (Robert L. Nuckolls, III) 8. 01:24 PM - Re: Feedback Request on Push-to-talk circuit... (idleup) 9. 01:33 PM - Re: Feedback Request on Push-to-talk circuit... (Robert L. Nuckolls, III) 10. 02:40 PM - Re: Feedback Request on Push-to-talk circuit... (idleup) 11. 03:46 PM - Re: Re: S704-1 Relay Question (John & Sue Dehnert) 12. 05:44 PM - Re: Questions for Bob after talking to B&C... (user9253) 13. 08:44 PM - Re: Questions for Bob after talking to B&C... (idleup) ________________________________ Message 1 _____________________________________ Time: 08:08:42 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Questions for Bob after talking to B&C... At 09:23 PM 4/29/2013, you wrote: > >Bob, > >Thanks for the response, but what about my question #1? should I do >the diode between the common and coil or just a standard jumper? I >also notice on the Z25L pdf that you linked to you have a diode >between the N.O. pin and the Coil as well. What are these for and >which method should I use? I'm not trying to be obtuse. Your question seems to offer the notion that there are errors of function between the various drawings cited. They all function as advertised with respect to the installation and operation of an SD-8 alternator. Yes, there are variations on a theme which are insignificant to the function. If you want me to pick one for you, then go with the wiring shown in Z-13/8. Bob . . . ________________________________ Message 2 _____________________________________ Time: 08:46:32 AM PST US Subject: AeroElectric-List: Re: S704-1 Relay Question From: "nuckollsr" 1. Am I correct that the S704-1 relay used for the backup alternator is wired to the regulator with the N.O. lead? There is nothing 'magic' about the N.O. terminal when you're using the relay as a single pole, single throw switch. Wire per the specific wiring diagram. 2. Can I use the N.C. lead for an "Aux Alt Offline" light? I assume this will be powered when the switch is off (or breaker tripped) right? Yes. 3. If I use an S704-1 relay for the E-Bus feed switch I would wire the Battery bus to the N.O. as well correct? In Z-13/8 the common is wired to the E-Bus but I am not sure if N.O. or N.C. is connected to the battery bus (it is not labeled) See question #1. 4. Lastly, if I want to add a light for when the E-Bus feed switch is closed where would I do that? it looks like when the switch is open the N.C. is powered from the Main bus and the N.O. powered from the battery bus, so I do not see where I would tap in a light that is only powered when the switch is closed. Should I just wire the light at the switch to accomplish this instead of at the relay (using Pin 1 on the switch?). Why would you want to do this? When the E-bus switch is closed, all items powered from the e-bus will be ON after the battery master is turned off. The E-Bus Alt Feed switch is part of power distribution and should be located right next to the ALT/BAT master. When parking the airplane, both switches would be DOWN. If you really need a light, it would wire in parallel with the coil of the e-bus alternate feed relay. Bob . . . Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399668#399668 ________________________________ Message 3 _____________________________________ Time: 10:18:23 AM PST US Subject: AeroElectric-List: Feedback Request on Push-to-talk circuit... From: "idleup" Would you guys be so kind as to tell me if the attach wiring diagram looks like it will work? I just need a simple push to test circuit for a few LED's I have. Thanks. - Matt Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399682#399682 Attachments: http://forums.matronics.com//files/ptt_circuit_116.png ________________________________ Message 4 _____________________________________ Time: 10:35:13 AM PST US Subject: AeroElectric-List: Re: S704-1 Relay Question From: "idleup" To answer the question as to why I would want an E-Bus feed indicator light there are a few reasons. Several VAF members have mentioned flying with the ebus switch closed under normal operations since any failure of the main bus circuit would then be automatically backed up. Another advantage is, when the ebus switch is closed you eliminate the voltage drop thru the Schottkey diode, which is not insignificant. Lastly, having the indicator would help to inadvertently drain the battery by forgetting to switch it off after the master is switched off. I understand your point that if you just make sure all the switches down then you would avoid this, but if I have and extra LED in my annunciator then it seems like a good application for using it. Thanks for the response. - Matt nuckollsr wrote: > 1. Am I correct that the S704-1 relay used for the backup alternator is wired to the regulator with the N.O. lead? > > There is nothing 'magic' about the N.O. terminal when you're using the relay as a single pole, single throw switch. Wire > per the specific wiring diagram. > > 2. Can I use the N.C. lead for an "Aux Alt Offline" light? I assume this will be powered when the switch is off (or breaker tripped) right? > > Yes. > > 3. If I use an S704-1 relay for the E-Bus feed switch I would wire the Battery bus to the N.O. as well correct? In Z-13/8 the common is wired to the E-Bus but I am not sure if N.O. or N.C. is connected to the battery bus (it is not labeled) > > See question #1. > > 4. Lastly, if I want to add a light for when the E-Bus feed switch is closed where would I do that? it looks like when the switch is open the N.C. is powered from the Main bus and the N.O. powered from the battery bus, so I do not see where I would tap in a light that is only powered when the switch is closed. Should I just wire the light at the switch to accomplish this instead of at the relay (using Pin 1 on the switch?). > > Why would you want to do this? When the E-bus switch is closed, all items powered from the e-bus will be ON after the battery master is turned off. The E-Bus Alt Feed switch is part of power distribution and should be located right next to the ALT/BAT master. When parking the airplane, both switches would be DOWN. If you really need a light, it would wire in parallel with the coil of the e-bus alternate feed relay. > > Bob . . . Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399683#399683 ________________________________ Message 5 _____________________________________ Time: 10:37:06 AM PST US Subject: AeroElectric-List: Re: Questions for Bob after talking to B&C... From: "idleup" I was not trying to imply that one was incorrect, I just do not understand the purpose of the diode in that application and whether it is necessary or not. B&C support was unable to tell me what it was there for either and directed me to ask you. - Matt nuckolls.bob(at)aeroelect wrote: > At 09:23 PM 4/29/2013, you wrote: > > > > > > > Bob, > > > > Thanks for the response, but what about my question #1? should I do > > the diode between the common and coil or just a standard jumper? I > > also notice on the Z25L pdf that you linked to you have a diode > > between the N.O. pin and the Coil as well. What are these for and > > which method should I use? > > > > > > I'm not trying to be obtuse. Your question seems > to offer the notion that there are errors of function > between the various drawings cited. They all function > as advertised with respect to the installation and > operation of an SD-8 alternator. Yes, there are > variations on a theme which are insignificant to > the function. > > If you want me to pick one for you, then go with > the wiring shown in Z-13/8. > > > > Bob . . . Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399684#399684 ________________________________ Message 6 _____________________________________ Time: 12:45:53 PM PST US From: "Vern Little" Subject: Re: AeroElectric-List: Feedback Request on Push-to-talk circuit... Hi Matt, I'm happy to help with this. First, I think that you need a few more isolating diodes. I don't know the characteristics of some of the inputs, so there is a possibility that they may provide a current path to ground (or power) when the push to test function is active. If you want more details, I could draw it up, but I think you can figure it out. However, and this is a big issue, you have a push to test function that checks whether reliable LEDs are functioning with an unreliable mechanical device... the relay. It is 10 to 100 times more likely to fail than the circuits you are testing. You are better off not having the push to test function at all. A better and more reliable solution if you want the test function is to get one of these: http://store.makerplane.org/annunciator-controller-il-4a/ It solves all of your problems. Vern -----Original Message----- From: idleup Sent: Tuesday, April 30, 2013 10:17 AM Subject: AeroElectric-List: Feedback Request on Push-to-talk circuit... Would you guys be so kind as to tell me if the attach wiring diagram looks like it will work? I just need a simple push to test circuit for a few LED's I have. Thanks. - Matt Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399682#399682 Attachments: http://forums.matronics.com//files/ptt_circuit_116.png ----- No virus found in this message. Checked by AVG - www.avg.com ________________________________ Message 7 _____________________________________ Time: 12:45:53 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: S704-1 Relay Question At 12:32 PM 4/30/2013, you wrote: To answer the question as to why I would want an E-Bus feed indicator light there are a few reasons. Several VAF members have mentioned flying with the ebus switch closed under normal operations since any failure of the main bus circuit would then be automatically backed up. Another advantage is, when the ebus switch is closed you eliminate the voltage drop thru the Schottkey diode, which is not insignificant. Lastly, having the indicator would help to inadvertently drain the battery by forgetting to switch it off after the master is switched off. I understand your point that if you just make sure all the switches down then you would avoid this, but if I have and extra LED in my annunciator then it seems like a good application for using it. I am mystified as to what kind of failure causes the main bus to go dark. The premise that 'automatic backup' of an unqualified failure mode is flawed. The voltage drop across the diode IS insignificant. DO-160 qualified electro-whizzies are shown to function down to 11 volts or less. 11 volts is end of battery life. When you're operating with a failed alternator, the e-bus alternate feed switch is closed and ALL e-bus gizmos are now EXPECTED to function as advertised BATTERY only . . . 12.5 down to 11.0 volts. With the alternator running, the main bus is 14.2 or greater. With even with a .7 volt rectifier drop, the e-bus is supported at 13.5 or so . . . 1 volt GREATER than the expected voltage for battery-only ops. Hence, voltage drop in the diode has no observable impact on system performance for devices powered from the e-bus. Concerns relieved by flying with the alternate feed switch closed are not based on demonstrable conditions. Forget . . . forget????? Do you not use a checklist for activities important the health, safety, comfort and lowest cost of ownership for your airplane? The e-bus alternate feed switch is usually pre-flight checked before the master is turned on. Power up the nav/com, get the ATIS and perhaps a clearance. Turn it back off, power up the main bus and start the engine. The e-bus alternate feed is not needed unless battery-only ops become necessary hence not likely to be left on either as a function of forgetfulness or lack of a documented procedure. Annunciators are a good thing for bringing CHANGES or DEPARTURES from normal/ideal conditions to the attention of a pilot. Low volts, low oil pressure, hydraulic pressure low, etc. Lights that stay on during normal ops are a potential distraction . . .this is why gear up-lock lights are NEVER included on an annunciator panel. If your e-bus alternate feed switch was closed when you landed, then there should have been a reason for it; a reason that indicates some repairs to the electrical system are in order. To my way of thinking, the darkest possible panel is ideal for night flight. For improved night vision and reduced reflections off the canopy . . . every source of illumination you can dim to barely visible or leave off entirely puts more risk-reduction points on your side of the blackboard. Bob . . . ________________________________ Message 8 _____________________________________ Time: 01:24:51 PM PST US Subject: AeroElectric-List: Re: Feedback Request on Push-to-talk circuit... From: "idleup" Thank you Vern, I appreciate your responding. I did not know the relay was such an unreliable device. I really do not want to spend $150 to test some LED lights (I am going to have more than 4). None of them are attached to sensors, they are all either power or ground switched 12v LEDs. I was going to look at the schematics for the device you linked too but the link to the open source files is broken, do you know a link that works? Also, do you think that a transistor based solution is more reliable than a relay? A while back Bob posted a drawing he did that used two transistors and four resistors to achieve the same one button design I did with a relay (see attached). Also, would the isolating diodes you referred to go on the other input line? I saw a design with those in there but did not understand why they were necessary... Let me know what you think... - Matt sprocket(at)vx-aviation.c wrote: > Hi Matt, I'm happy to help with this. > > First, I think that you need a few more isolating diodes. I don't know the > characteristics of some of the inputs, so there is a possibility that they > may provide a current path to ground (or power) when the push to test > function is active. If you want more details, I could draw it up, but I > think you can figure it out. > > However, and this is a big issue, you have a push to test function that > checks whether reliable LEDs are functioning with an unreliable mechanical > device... the relay. It is 10 to 100 times more likely to fail than the > circuits you are testing. You are better off not having the push to test > function at all. > > A better and more reliable solution if you want the test function is to get > one of these: > > http://store.makerplane.org/annunciator-controller-il-4a/ > > It solves all of your problems. > > Vern > > -- Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399698#399698 Attachments: http://forums.matronics.com//files/one_button_ptt_for_pu_pd_annunciation_cluster_177.pdf ________________________________ Message 9 _____________________________________ Time: 01:33:55 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Feedback Request on Push-to-talk circuit... At 12:17 PM 4/30/2013, you wrote: > >Would you guys be so kind as to tell me if the attach wiring diagram >looks like it will work? I just need a simple push to test circuit >for a few LED's I have. Thanks. > >- Matt > > Why are you doing press to test on LEDs? Incandescent bulbs as warning devices begged for press to test given that their demonstrated service life was a fraction of that for the airplane. On the other hand, LEDs will outlive the machine. All of those LEDs can be tested during normal pre-flight procedures. In other words, NOT seeing a light when it is expected to be operating is a more relevant test than having the light respond to a press-to-test switch. Press-to-test circuits test a button, a bulb and in your example, a relay. The fact that the light DID come on says nothing about the electro- whizzy that drives it. On the other hand, seeing one of those lights illuminate when it is EXPECTED to do so is 100% assurance for both the bulb and the integrity of the annunciator signal that drives it. Bob . . . ________________________________ Message 10 ____________________________________ Time: 02:40:41 PM PST US Subject: AeroElectric-List: Re: Feedback Request on Push-to-talk circuit... From: "idleup" nuckolls.bob(at)aeroelect wrote: > At 12:17 PM 4/30/2013, you wrote: > > > > > > > Would you guys be so kind as to tell me if the attach wiring diagram > > looks like it will work? I just need a simple push to test circuit > > for a few LED's I have. Thanks. > > > > - Matt > > > > > > > > > > Why are you doing press to test on LEDs? > > Incandescent bulbs as warning devices begged > for press to test given that their demonstrated > service life was a fraction of that for the > airplane. On the other hand, LEDs will outlive the machine. > > All of those LEDs can be tested during normal > pre-flight procedures. In other words, NOT > seeing a light when it is expected to be operating > is a more relevant test than having the light > respond to a press-to-test switch. > > Press-to-test circuits test a button, a bulb > and in your example, a relay. The fact that the > light DID come on says nothing about the electro- > whizzy that drives it. > > On the other hand, seeing one of those lights > illuminate when it is EXPECTED to do so is 100% > assurance for both the bulb and the integrity > of the annunciator signal that drives it. > > > > > Bob . . . The best answer I could give you is because I thought you were supposed to have a "Push to test" function for your annunciators. If it is not necessary for LED's than I am more than happy to ditch the whole thing. Less parts, less complexity... - Matt Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399704#399704 ________________________________ Message 11 ____________________________________ Time: 03:46:43 PM PST US From: "John & Sue Dehnert" Subject: Re: AeroElectric-List: Re: S704-1 Relay Question If you want a E-Bus feed indicator light wire the low oil pressure warning light through the E-Bus. John. ----- Original Message ----- From: "idleup" Sent: Wednesday, May 01, 2013 3:32 AM Subject: AeroElectric-List: Re: S704-1 Relay Question > > To answer the question as to why I would want an E-Bus feed indicator > light there are a few reasons. Several VAF members have mentioned flying > with the ebus switch closed under normal operations since any failure of > the main bus circuit would then be automatically backed up. Another > advantage is, when the ebus switch is closed you eliminate the voltage > drop thru the Schottkey diode, which is not insignificant. Lastly, having > the indicator would help to inadvertently drain the battery by forgetting > to switch it off after the master is switched off. I understand your point > that if you just make sure all the switches down then you would avoid > this, but if I have and extra LED in my annunciator then it seems like a > good application for using it. > > Thanks for the response. > > - Matt > > > nuckollsr wrote: >> 1. Am I correct that the S704-1 relay used for the backup alternator is >> wired to the regulator with the N.O. lead? >> >> There is nothing 'magic' about the N.O. terminal when you're using the >> relay as a single pole, single throw switch. Wire >> per the specific wiring diagram. >> >> 2. Can I use the N.C. lead for an "Aux Alt Offline" light? I assume this >> will be powered when the switch is off (or breaker tripped) right? >> >> Yes. >> >> 3. If I use an S704-1 relay for the E-Bus feed switch I would wire the >> Battery bus to the N.O. as well correct? In Z-13/8 the common is wired to >> the E-Bus but I am not sure if N.O. or N.C. is connected to the battery >> bus (it is not labeled) >> >> See question #1. >> >> 4. Lastly, if I want to add a light for when the E-Bus feed switch is >> closed where would I do that? it looks like when the switch is open the >> N.C. is powered from the Main bus and the N.O. powered from the battery >> bus, so I do not see where I would tap in a light that is only powered >> when the switch is closed. Should I just wire the light at the switch to >> accomplish this instead of at the relay (using Pin 1 on the switch?). >> >> Why would you want to do this? When the E-bus switch is closed, all items >> powered from the e-bus will be ON after the battery master is turned off. >> The E-Bus Alt Feed switch is part of power distribution and should be >> located right next to the ALT/BAT master. When parking the airplane, >> both switches would be DOWN. If you really need a light, it would wire in >> parallel with the coil of the e-bus alternate feed relay. >> >> Bob . . . > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=399683#399683 > > > ________________________________ Message 12 ____________________________________ Time: 05:44:18 PM PST US Subject: AeroElectric-List: Re: Questions for Bob after talking to B&C... From: "user9253" Matt, Bob's and B&C's drawings do not conflict. They are different. There are many different ways to wire an aircraft. I suggest that you use one of Bob's drawings because his are for the whole electrical system, not just a part of it. Z-13/8 Rev Q has two diodes connected to the dynamo relay. These diodes potentially provide power to the relay from two sources: 1. The main power bus. 2. The dynamo. The diodes isolate the two sources from each other until the relay is energized Z-13/8 Rev R does not have diodes. You asked which drawing to use. I suggest Z-13/8 Rev R with a minor change: Move the jumper from the common terminal of the dynamo relay to the normally open terminal. The reason is that there could be a failure mode when there is no power available at the main power bus to operate the dynamo relay. There will always be power available from the dynamo. And if there isn't, then there is no reason to turn the dynamo relay on. Perhaps Bob will comment on this suggestion. > 1. Am I correct that the S704-1 relay used for the backup alternator is wired to the regulator with the N.O. lead? Yes > 2. Can I use the N.C. lead for an "Aux Alt Offline" light? I assume this will be powered when the switch is off (or breaker tripped) right? Yes and Yes. But why have a light? It will always be on. Lights should warn of an unusual situation. > 3. If I use an S704-1 relay for the E-Bus feed switch I would wire the Battery bus to the N.O. as well correct? Yes The two parallel lines below the relay coil represent the metal core of the relay. When the coil is energized, the core becomes a magnet and pulls the movable contact towards the core and towards the normally open contact. So the contact closest to the core is N.O. > 4. Lastly, if I want to add a light for when the E-Bus feed switch is closed where would I do that? it looks like when the switch is open the N.C. is powered from the Main bus and the N.O. powered from the battery bus, so I do not see where I would tap in a light that is only powered when the switch is closed. Should I just wire the light at the switch to accomplish this instead of at the relay (using Pin 1 on the switch?). > I think that a light will be useful to warn you if the E-Bus switch has been left on after shutdown. You do not want the battery to run down. You are correct that there will be power on both the N.O. and COM relay terminals. A light can not be connected there. And a light can not be connected to terminal 1 of the switch because it will be in series with the relay coil. In that case, the light could illuminate dimly with the switch off. Or the relay might not shut off with the switch. Of course the light will not illuminate with the switch on because the light will then have ground connected to both of its terminals. Use a DPST or a DPDT switch for the E-Bus relay. One half of the switch will operate the relay and the other half will operate the light. Joe -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=399721#399721 ________________________________ Message 13 ____________________________________ Time: 08:44:24 PM PST US Subject: AeroElectric-List: Re: Questions for Bob after talking to B&C... From: "idleup" user9253 wrote: > Matt, > Bob's and B&C's drawings do not conflict. They are different. There are many different ways to wire an aircraft. I suggest that you use one of Bob's drawings because his are for the whole electrical system, not just a part of it. > Z-13/8 Rev Q has two diodes connected to the dynamo relay. These diodes potentially provide power to the relay from two sources: 1. The main power bus. 2. The dynamo. The diodes isolate the two sources from each other until the relay is energized > Z-13/8 Rev R does not have diodes. > You asked which drawing to use. I suggest Z-13/8 Rev R with a minor change: Move the jumper from the common terminal of the dynamo relay to the normally open terminal. The reason is that there could be a failure mode when there is no power available at the main power bus to operate the dynamo relay. There will always be power available from the dynamo. And if there isn't, then there is no reason to turn the dynamo relay on. Perhaps Bob will comment on this suggestion. > > > 1. Am I correct that the S704-1 relay used for the backup alternator is wired to the regulator with the N.O. lead? > > Yes > > > 2. Can I use the N.C. lead for an "Aux Alt Offline" light? I assume this will be powered when the switch is off (or breaker tripped) right? > > Yes and Yes. But why have a light? It will always be on. Lights should warn of an unusual situation. > > > 3. If I use an S704-1 relay for the E-Bus feed switch I would wire the Battery bus to the N.O. as well correct? > > Yes > The two parallel lines below the relay coil represent the metal core of the relay. When the coil is energized, the core becomes a magnet and pulls the movable contact towards the core and towards the normally open contact. So the contact closest to the core is N.O. > > > 4. Lastly, if I want to add a light for when the E-Bus feed switch is closed where would I do that? it looks like when the switch is open the N.C. is powered from the Main bus and the N.O. powered from the battery bus, so I do not see where I would tap in a light that is only powered when the switch is closed. Should I just wire the light at the switch to accomplish this instead of at the relay (using Pin 1 on the switch?). > > > > I think that a light will be useful to warn you if the E-Bus switch has been left on after shutdown. You do not want the battery to run down. You are correct that there will be power on both the N.O. and COM relay terminals. A light can not be connected there. And a light can not be connected to terminal 1 of the switch because it will be in series with the relay coil. In that case, the light could illuminate dimly with the switch off. Or the relay might not shut off with the switch. Of course the light will not illuminate with the switch on because the light will then have ground connected to both of its terminals. Use a DPST or a DPDT switch for the E-Bus relay. One half of the switch will operate the relay and the other half will operate the light. > Joe Thanks Joe, What happens if the Aux alternator is turned on while under normal operations and both alternators are feeding the electrical system at one time? As for the ebus feed light, what about putting the anode of the LED on the N.O. contact of the relay (coming from the battery bus) and the cathode on the side of the coil where the switch is connected? 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