AeroElectric-List Digest Archive

Sun 09/23/18


Total Messages Posted: 10



Today's Message Index:
----------------------
 
     1. 10:36 AM - Re: Re: Alternator/shunt question (Robert L. Nuckolls, III)
     2. 11:01 AM - Re: Re: Alternator/shunt question (FLYaDIVE)
     3. 03:03 PM - Fw: Hello everyone , new here and need some help ! (Neil Parkinson)
     4. 04:37 PM - Re: Alternator/shunt question (woxofswa)
     5. 06:36 PM - Re: Re: Alternator/shunt question (Robert L. Nuckolls, III)
     6. 07:11 PM - Re: Fw: Hello everyone , new here and need some help ! (Robert L. Nuckolls, III)
     7. 07:51 PM - What to monitor in a dual alternator airplane (Art Zemon)
     8. 08:18 PM - Re: Alternator/shunt question (user9253)
     9. 09:08 PM - Re: What to monitor in a dual alternator airplane (FLYaDIVE)
    10. 10:51 PM - Re: Alternator/shunt question (woxofswa)
 
 
 


Message 1


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    Time: 10:36:36 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Alternator/shunt question
    At 09:22 PM 9/22/2018, you wrote: > >Myron, based on your description, I agree that the aux alternator is >putting out 7 amps. Perhaps the alternator is not spinning fast >enough to generate its rated capacity. > Looking at the attached picture from a Dynon manual, confirm that > the shunt is in location A, and not B or C. > >-------- >Joe Gores > Do I assume correctly that we're talking about a BC-462 alternator? Referring to B&C published data . . . Emacs! . . . the alternator is capable of at least 40A of output at nominal cruise rpms on any engine. Assuming that your current sensor is indeed installed as a battery ammeter -and- you're seeing -2A with the standby alternator ON, then we have to deduce that your bus voltage under this test condition is WAaayyyy too low . . . the battery is still supply a portion of the ship's running loads. You did not mention any observed voltage readings and as Joe suggests it would be helpful to confirm the actual location of your Dynon sensor in the system. What votlage regulator are you using on the standby alternator? Adjustable? Was it checked and adjusted as necessary at time of installation? Bob . . .


    Message 2


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    Time: 11:01:52 AM PST US
    From: FLYaDIVE <flyadive@gmail.com>
    Subject: Re: Alternator/shunt question
    On Sat, Sep 22, 2018 at 6:28 PM Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > At 02:04 PM 9/22/2018, you wrote: > > > Thanks for the responses. Let me break the scenario down further. > > I recently installed the B&C 30 amp backup alternator. > > On my first longish flight to test the system I flew with basic essential s > running at 2500 rpm. Turning off both alternators, my ammeter read minus > (-9) Amps at 12.5 volts. > > Barry - That indicates your system load is 9 Amps. > Turning on the standby alternator, the ammeter showed minus (-2) amps at > 12.9 volts which stayed more or less constant for several minutes. > > Barry - Here there are a few items and questions: 9 Amps - 2 Amps = 7 Amps That indicated the Standby Alt is supplying 7 Amps to the electrical system load. Which is what the LOAD is! Question: So, why is the LOAD without both alternators off Higher than the Load with one alternator? Question: Why do you say : "... 12.9 volts which stayed more or less constant for several minutes."? Are you referring to the voltage and the subsequent drop from 12.9 to 12.5 VDC? If so, then the backup alternator is NOT putting out the required voltage. The 12.5 VDC on the load is LOW as you require 13.8 - 14.2 VDC to charge a battery. What should have been your next TEST would be to: Shut off the Stand-by Alt and turn on the Main Alt. IF the VOLTAGE from the Main Alt was 13.8 to 14.2 VDC then you can say the output of the Main Alt is correct. Follow that up with: What is the Indicated Current draw with the Main Alt? IF the Main Alt is putting out the proper power you should see 9 Amps being supplied to the electrical Load for the Same Configuration as you checked things previously. Another very simple test would be to disconnect one lead from the battery and hook an Ammeter in series. Use a good digital Ammeter and see what the current draw is. For the same configuration as in your test it should be no less than the 9 Amps. Slightly more when the engine is running due to the extra draw of the NON PM Alt's FIELD. Obviously the backup is producing power, it just doesn=C3=A2=82=AC=84 =A2t seem to be > producing as much as I was expecting at what looks to me to be about 7 > Amps. What I am trying to determine is if it is a low production issue, > false indication issue, or a misinterpretation of correct indications. > > Barry - If you do the above testing, the answer to this question will present itself. Best of luck, Barry > > If your ammeter does indeed produce minus readings > with the alternator(s) OFF, then it is indeed > wired as a battery ammeter and should have NO > b-lead wires running through it. > > If the standby alternator boosts the bus voltage > to something greater than 13.5 volts, then it > is carrying ALL system loads and perhaps adding > a bit to recharging the battery. > > If this condition is true, then the alternator > is just fine irrespective of what the b-lead > current might be. > > An alternator under regulation will deliver > no more current than the system demands of it. > B-lead current will be electro-whizzie demands > added to battery demands . . . and could > be quite low. If your bus voltage is correct, > then the alternator is fine. > > Can you publish a schematic of how the current > sensor is installed in your system? > > > Bob . . . >


    Message 3


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    Time: 03:03:43 PM PST US
    From: Neil Parkinson <nwparkinson@btinternet.com>
    Subject: Fwd: Hello everyone , new here and need some help !
    > Hi all > > Im building an Rv8 and would like to make it IFR with a Garmin g3x fit . > > After reading the excellent online book Aeroelectric Connection i intend to use the system 13/8 with B&C parts . (Attached Diagram ) > > I however have a few questions , as my school boy electrics is struggling ! > > 1)What happens to an Alternator ( in this case the SD-8) when it reaches its max current capacity , does it get hot and eventually blow , or does it just start decreasing its voltage output , eventually going below the battery voltage causing a current drain from the Batt ? > > 2) If its the former I'm thinking following a Main Alternator failure if the Aux Alternator is turned on ( without opening the main battery contactor ) maybe there is room to overload this too ? If so i was thinking maybe an improvement to this system would be an interlock that when the E-Bus and Aux Alt are activated they open the ground to the battery contactor coil and thus prevent an overload of the emergency system ? Maybe you could have a guarded 3 posn switch that on first click , opens the main battery contactor and closes the E-Bus Alternate feed , then second click closes the AUX - Alt feed relay ? A one switch saves the day sort of thing ?? > > 3) It would be nice to have a CAS message on my Garmin G3x that indicates if the SD-8 is functioning ok incase of a main failure . Im thinking of a =9CStandby Alt Fail =9C caption that would indicate when ever the SD-8 is not producing power and ready for an emergency . What sort of output would an unloaded ( Supply relay open ) Sd-8 be producing ? unstable , high , low or on task at 12v?? How can i send a =9CI'm functioning ok and producing power =9C signal ? Maybe a relay coil on its output that closes a signal to the G3X ?? ( see my hand drawing ) > > But maybe id need diode after that coil to ensure its only Aux Alt that can close it and not reverse supply ?? What would a Diode in the line do to supply voltage ?? How could i make it so the relay closes at 12ish volts ?? > > Any better ideas ?? > > Too many questions I know ! > > Thank you so much for any help ! > > Neil


    Message 4


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    Time: 04:37:02 PM PST US
    Subject: Re: Alternator/shunt question
    From: "woxofswa" <woxof@aol.com>
    My primary alt is a plane power 60A internally regulated. The B-lead connects to the load bus at the 60A C/B. From the load bus a lead ties to the input of the shunt. The output of the shunt goes to the starter relay. When the primary is functioning, the reading is always Positive, usually in the low teens after start which slowly works its way down to zero or one on a long flight. The backup is a B&C 30A BC410-H regulated by a SB1B linear standby regulator. Its B lead output runs to a 30A current limiter and then to the input of the shunt thereby tying to the tying to the starter relay with the same output cable as the primary. The standby is set by the factory at 13 VDC. The reading in flight is 14.3 VDC and 1 amp with primary operating. It is 12.5 VDC and MINUS 9 A with both Alts off It is 12.9 VDC and minus 2 A with the backup only operating. -------- Myron Nelson Mesa, AZ Flew May 10 2014 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=483332#483332


    Message 5


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    Time: 06:36:14 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Alternator/shunt question
    At 06:36 PM 9/23/2018, you wrote: > >My primary alt is a plane power 60A internally >regulated. The B-lead connects to the load bus >at the 60A C/B. From the load bus a lead ties to >the input of the shunt. The output of the shunt >goes to the starter relay. When the primary is >functioning, the reading is always Positive, >usually in the low teens after start which >slowly works its way down to zero or one on a long flight. which is what battery ammeters do >The backup is a B&C 30A BC410-H regulated by a >SB1B linear standby regulator. It=99s B lead >output runs to a 30A current limiter and then to >the input of the shunt thereby tying to the >tying to the starter relay with the same output cable as the primary. When you say 'shunt' are you speaking of the Dynon current sensor? Not sure why the b-leads are running through the current sensor if you're intended it to function as a battery ammeter. >The standby is set by the factory at 13 VDC. ' Which explains your readings. 13.0 is too low to completely relieve the ship's battery of a few amps of load. Adjust your sb-1 up to 13.5 >The reading in flight is 14.3 VDC and 1 amp with primary operating. > >It is 12.5 VDC and MINUS 9 A with both Alts off > >It is 12.9 VDC and minus 2 A with the backup only operating. SB-1 is set too low. It only needs to be 0.7v or so below your main alternator set point. Bob . . .


    Message 6


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    Time: 07:11:03 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Fwd: Hello everyone , new here and need some
    help ! >Im building an Rv8 and would like to make it IFR with a Garmin g3x fit . > > >After reading the excellent online book Aeroelectric Connection i >intend to use the system 13/8 with B&C parts . (Attached Diagram ) > >I however have a few questions , as my school boy electrics is struggling ! > > >1)What happens to an Alternator ( in this case the SD-8) when it >reaches its max current capacity , does it get hot and eventually >blow , or does it just start decreasing its voltage output , >eventually going below the battery voltage causing a current drain >from the Batt ? > > Yes . . . the bus simply sags until the > battery picks up the slack. Nothing smokes. > BUT . . . you should configure your ENDURANCE > loads to remain at or just below the maximum > output of the SD8 which is on the order of > 10A. This is your en route configuration. > > Then, when it's time for descent and approach > to landing, you can turn on all the goodies > and use SD8+battery to complete the flight. > > This holds ship's battery energy in reserve > > >2) If its the former I'm thinking following a Main >Alternator failure if the Aux Alternator is turned on ( without >opening the main battery contactor ) maybe there is room to overload >this too ? If so i was thinking maybe an improvement to this system >would be an interlock that when the E-Bus and Aux >Alt are activated they open the ground to the battery contactor >coil and thus prevent an overload of the emergency system ? Maybe >you could have a guarded 3 posn switch that on first click , opens >the main battery contactor and closes the E-Bus Alternate feed , >then second click closes the AUX - Alt feed relay ? A one switch >saves the day sort of thing ?? > > Why so much monkey-motion? If the main alterantor > fails you get a low volts warning whereupon you > finish your cup of coffee before configuring > to endurance mode by: > > E-Bus alt feed closed > > DC PWR master OFF > > Reduce loads on E-bus to 10A or less > if needed. > > On descent and approach, delay bringing > any other electro-whizzies on for as long > as practical, then move DC PWR master to > BAT and continue normal ops to the > runway. > >3) It would be nice to have a CAS message on my Garmin G3x that >indicates if the SD-8 is functioning ok incase of a main failure . >Im thinking of a "Standby Alt Fail " caption that would indicate >when ever the SD-8 is not producing power and ready for an emergency >. What sort of output would an unloaded ( Supply relay open ) Sd-8 >be producing ? unstable , high , low or on task at 12v?? How can i >send a "I'm functioning ok and producing power " signal ? Maybe a >relay coil on its output that closes a signal to the G3X ?? ( see my >hand drawing ) > >But maybe id need diode after that coil to ensure its only Aux Alt >that can close it and not reverse supply ?? What would a Diode in >the line do to supply voltage ?? How could i make it so the relay >closes at 12ish volts ?? > > >Any better ideas ?? > > >Too many questions I know ! > > >Thank you so much for any help ! > > Z13/8 is about the most reliable system > flying in light aircraft today. It's light, > low cost, has an excellent FMEA outcome > and no downstream periodic/preventative > maintenance for continued airworthiness. > > If the G3X has a low voltage annunciation > feature, program it for about 13.0 volts. > That's all you need. Bob . . .


    Message 7


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    Time: 07:51:17 PM PST US
    From: Art Zemon <art@zemon.name>
    Subject: What to monitor in a dual alternator airplane
    Folks, Over the years that I subscribed to this mailing list, there have been many conversations about monitoring voltage and current in an airplane. I want to approach this from a different perspective and see if I understand correctly. The basic questions are: 1. What should I monitor in my airplane? 2. How do I interpret the indications, especially in flight? My own airplane has a 12 volt system with two B&C alternators and voltage regulators. The primary regulator is an LR3C preset to 14.4 volts. The standby regulator is part of an SB1B-14 and is preset to 13.0 volts. Here is what I think that I need to monitor: - Voltage (should pretty pretty much the same everywhere so I am just using my EFIS' bus voltage indicator) - Current (I strapped a solid state current sensor to the wire going from the master contactor to the fuse block) - Primary regulator overvoltage indicator - Standby regulator overvoltage indicator - Primary regulator/alternator ON (physical switch turned on) - Standby regulator/alternator ON (physical switch turned on) And here is how I think I should interpret stuff: - Voltage approximately 14.4 volts: Everything is happy with the primary alternator and regulator doing their things. - Voltage approximately 13.0 volts: My primary alternator isn't providing power or my primary regulator isn't working properly. Check that the primary alternator switch is turned on. If the standby regulator does not have an overvoltage indication then it is operating normally and I do not have a flight urgency. - Voltage lower than 13.0 volts: I have problems with both regulators/alternators and I am depleting the battery. This needs attention. - If the voltage is lower than 13.0 volts, check that the alternator switches are turned on. If both are turned on and voltage is still low, check the current draw. At cruise RPM, I can expect 30 amps from the standby alternator. I need to intelligently balance load and amps available (governed by engine RPM) against battery capacity and remaining flight duration. - Voltage higher than 14.4 volts: The overvoltage protection in the primary regulator has failed. Turn off the primary alternator. Do I have it right? -- Art Z. -- https://CheerfulCurmudgeon.com/ *"We do not see the world as it is. We see the world as we are."*


    Message 8


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    Time: 08:18:54 PM PST US
    Subject: Re: Alternator/shunt question
    From: "user9253" <fransew@gmail.com>
    Myron, >From your description, I deduce that the shunt is located in position "A" in the picture in my previous post. All voltmeter and ammeter indications are correct. Like Bob said, the standby alternator voltage is set too low. I suspect that on a long flight of an hour or more with the main alternator off and the standby alternator on, that the voltage will go down a tenth or two and the amps would slowly rise from -2 to zero. You could leave it like that, but the battery will not be fully charged at your destination. It is best to increase the voltage of the standby regulator like Bob said. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=483337#483337


    Message 9


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    Time: 09:08:08 PM PST US
    From: FLYaDIVE <flyadive@gmail.com>
    Subject: Re: What to monitor in a dual alternator airplane
    Art: On Sun, Sep 23, 2018 at 10:55 PM Art Zemon <art@zemon.name> wrote: > Folks, > > Over the years that I subscribed to this mailing list, there have been > many conversations about monitoring voltage and current in an airplane. I > want to approach this from a different perspective and see if I understand > correctly. > > The basic questions are: > > 1. What should I monitor in my airplane? > 2. How do I interpret the indications, especially in flight? > > My own airplane has a 12 volt system with two B&C alternators and voltage > regulators. The primary regulator is an LR3C preset to 14.4 volts. The > standby regulator is part of an SB1B-14 and is preset to 13.0 volts. > Barry - Why would you have the second Alt. set to ANYTHING less than the charging voltage? 13.0 VDC is NOT a Charging Voltage. Minimum Charging Voltage is 13.8 VDC with a Max around 14.5 VDC. For some reason people can not agree on the Max. Voltage. It is usually 14.2 to 14.5 VDC. > > Here is what I think that I need to monitor: > > - Voltage (should pretty pretty much the same everywhere so I am just > using my EFIS' bus voltage indicator) > - Current (I strapped a solid state current sensor to the wire going > from the master contactor to the fuse block) > - Primary regulator overvoltage indicator > - Standby regulator overvoltage indicator > - Primary regulator/alternator ON (physical switch turned on) > - Standby regulator/alternator ON (physical switch turned on) > > And here is how I think I should interpret stuff: > > - Voltage approximately 14.4 volts: Everything is happy with the > primary alternator and regulator doing their things. > - Voltage approximately 13.0 volts: My primary alternator isn't > providing power or my primary regulator isn't working properly. > > Barry - Forget about the 13.0 VDC. It is too low. And only shows the output of your #2 Alt is not sufficient to charge a battery. If you see BATTERY VOLTAGE anything around 12.5 VDC or Less you are running on battery and that is not good. > - Check that the primary alternator switch is turned on. If the > standby regulator does not have an overvoltage indication then it is > operating normally and I do not have a flight urgency. > > Barry - What is "normal" if you are NOT putting out a voltage that will charge the battery? You are already below normal. An idiot light is a back-up to a volt meter. If the bulb goes in the idiot light you are relying on something that will never work. If the volt meter shows a failure you KNOW there is something wrong and cross check to the idiot light. BUT! That is ONLY for a LOW voltage. What about OVER VOLTAGE? If the volt meter failed and NOW it is time to check if the Idiot light says the same thing. > > - Voltage lower than 13.0 volts: I have problems with both > regulators/alternators and I am depleting the battery. This needs attention. > - If the voltage is lower than 13.0 volts, check that the alternator > switches are turned on. If both are turned on and voltage is still low, > check the current draw. At cruise RPM, I can expect 30 amps from the > standby alternator. > > Barry - Not correct! The Alt Systems has the ability to SUPPLY 30 Amps. BUT! That is ONLY if the Load on the plane is 30 Amps. > > - I need to intelligently balance load and amps available (governed by > engine RPM) against battery capacity and remaining flight duration. > > Barry - You do not have to balance anything. That is the job of ACU's. What you should have done during designing and building your plane is: Figure out ALL your electrical equipment draw and add a bit for future expansion AND THEN pick a Primary Alt that can supply 20% Greater than the Full Load. > > - Voltage higher than 14.4 volts: The overvoltage protection in the > primary regulator has failed. Turn off the primary alternator. > > Barry - YES! But, don't stop there. What if the over-voltage condition is coming from the back-up Alt? Side Note: It is standard practice to crosscheck against at least two instruments. Barry "If you wash your hands before you go to the bathroom you might have the making of a crew chief." > Do I have it right? > > -- Art Z. > > -- > https://CheerfulCurmudgeon.com/ > > *"We do not see the world as it is. We see the world as we are."* >


    Message 10


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    Time: 10:51:55 PM PST US
    Subject: Re: Alternator/shunt question
    From: "woxofswa" <woxof@aol.com>
    Thanks guys. I tied the standby into the shunt simply because it was an easy and efficient way location wise to tie it to the system, and I hoped it would still provide some useful information. -------- Myron Nelson Mesa, AZ Flew May 10 2014 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=483339#483339




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