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B&C SD-8 Alternator/Regulator

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ron228rj(at)gmail.com
Guest

Posted: Tue Aug 25, 2020 11:40 am Post subject: B&C SD-8 Alternator/Regulator

Due to some strange behavior on my EFIS shortly after takeoff, I theorized that I might have a noisy electrical system that was causing EFIS problems. The charging system (SD- doesn't kick in until I take off and achieve higher RPM. I could not reproduce the problem on the ground so I could not easily hook up an oscilloscope. Maybe because static runs don't achieveÂ the same RPM at full throttle, and high speed taxi runs on a 3000 ft runway achieve higher RPM but don't last long enough?



So, I did another flight and took off and when the problemÂ happened again, I turned off the alternator so I was just running on the battery. The EFIS problems continued so I don't believe I have a noisy electrical system causing the problem. I also swapped out the regulator and replaced the battery just to be thorough!

My real question is related to what happens when I disconnect a PM alternator from the electrical system between the regulator and the bus. Does it keep generating 8 amps that now has to be dissipated as heat by the voltage regulator? I did notice some noise, or a change in the noise, in my headset when I disconnected the alternator/regulator.

Also, what would happen if I disconnected the two leads for the alternator so that they weren't even connected to a regulator?

Thanks,

Ron

nuckolls.bob(at)aeroelect
Guest

Posted: Tue Aug 25, 2020 1:29 pm Post subject: B&C SD-8 Alternator/Regulator

At 02:35 PM 8/25/2020, you wrote:

  	  Quote: 	
		  Due to some strange behavior on my EFIS shortly after takeoff, I theorized that I might have a noisy electrical system that was causing EFIS problems. 	


   Is this a new condition or has always

   existed?



  	  Quote: 	
		  The charging system (SD- doesn't kick in until I take off and achieve higher RPM. I could not reproduce the problem on the ground so I could not easily hook up an oscilloscope. Maybe because static runs don't achieveÂ the same RPM at full throttle, and high speed taxi runs on a 3000 ft runway achieve higher RPM but don't last long enough? 	


   Fair hypothesis . . .



 

  	  Quote: 	
		  So, I did another flight and took off and when the problemÂ happened again, I turned off the alternator so I was just running on the battery. The EFIS problems continued so I don't believe I have a noisy electrical system causing the problem. I also swapped out the regulator and replaced the battery just to be thorough! 	


   Good . . .



 

  	  Quote: 	
		  My real question is related to what happens when I disconnect a PM alternator from the electrical system between the regulator and the bus. Does it keep generating 8 amps that now has to be dissipated as heat by the voltage regulator? I did notice some noise, or a change in the noise, in my headset when I disconnected the alternator/regulator. 	


   Depends on the pedigree of the regulator.

   Some designs do indeed 'short' the alternator

   windings to regulate power at the battery.

   When ship's systems are using power, the need

   to short-out excess energy is minimized. But

   you're right, if this is a shunt style R/R,

   reducing output current to zero MAY cause

   the regulator to severely abuse the alternator

   mistakenly thinking that ship's loads are still

   there . . . just very small.



  	  Quote: 	
		  Also, what would happen if I disconnected the two leads for the alternator so that they weren't even connected to a regulator? 	


   Conduct the experiment. Opening the AC power

   BETWEEN alternator and rectifier/regulator is

   the preferred method for shutting down the

   system. All energies in the alternator

   system go to zero. See:



  https://tinyurl.com/7vp9g4e



   Unhook the alternator and do a battery only

   flight.



 

   Bob . . .

ron228rj(at)gmail.com
Guest

Posted: Tue Aug 25, 2020 2:27 pm Post subject: B&C SD-8 Alternator/Regulator

On Tue, Aug 25, 2020 at 5:34 PM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



 	  Quote: 	
		    At 02:35 PM 8/25/2020, you wrote:

  	  Quote: 	
		  Due to some strange behavior on my EFIS shortly after takeoff, I theorized that I might have a noisy electrical system that was causing EFIS problems. 	


 Â  Is this a new condition or has always

 Â  existed?



	




I thought it was a new condition. My plane has been down for quite a while during an engine rebuild. I am trying to fly it and monitor temperatures on my new engine but all the engine data is fluctuatingÂ wildly. I looked back at some old data and I could see the same symptoms occasionally, but it was more mild and very infrequent. I just never noticed it. Now, it is happening nearly continuously and the variations are far more extreme. The EFIS has three other issues as well. It has lost the GPS signal, it always stops recording data to the USB stick once the temperature oscillations start, and it only sometimes displays the ADSB-in data that I am feeding it. One thing in common with all of these is that they are connected to serial ports on the EFIS. Either four things just simultaneously failed or there is a problem with the EFIS serial ports. That's my current theory.

 	  Quote: 	
		   	  Quote: 	
		  Also, what would happen if I disconnected the two leads for the alternator so that they weren't even connected to a regulator? 	


 Â  Conduct the experiment. Opening the AC power

 Â  BETWEEN alternator and rectifier/regulator is

 Â  the preferred method for shutting down the

 Â  system. All energies in the alternator

 Â  system go to zero. See:



  https://tinyurl.com/7vp9g4e



 Â  Unhook the alternator and do a battery only

 Â  flight.

	




Yes, that is exactly what I am planning for the next flight. Additionally, the EIS is remotely mounted but it has a display. I intend to fly with a GoPro aimed at it to see if the CHT values that it displays match those on the EFIS. If there is simply a communication problem or some source of noise in the EFIS, then the EIS should be displaying the correct CHT values and not wildly fluctuating.

Ron

Â

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Aug 26, 2020 6:26 am Post subject: B&C SD-8 Alternator/Regulator

 	  Quote: 	
		    Â  Is this a new condition or has always

  Â  existed?

  

 I thought it was a new condition. My plane has been down for quite a while during an engine rebuild. I am trying to fly it and monitor temperatures on my new engine but all the engine data is fluctuatingÂ wildly. I looked back at some old data and I could see the same symptoms occasionally, but it was more mild and very infrequent. I just never noticed it. Now, it is happening nearly continuously and the variations are far more extreme. The EFIS has three other issues as well. It has lost the GPS signal, it always stops recording data to the USB stick once the temperature oscillations start, and it only sometimes displays the ADSB-in data that I am feeding it. One thing in common with all of these is that they are connected to serial ports on the EFIS. Either four things just simultaneously failed or there is a problem with the EFIS serial ports. That's my current theory. 	


    Serial data are pretty robust with respect

    to noises . . . I'm pondering the possibility

    of a grounding issue for the analog inputs.

    Analog temperature data signals, whether thermocouple

    or RTC are small and the fact that the whole

    suite of measurements are flaky suggests

    something common to signal conditioning.



  	  Quote: 	
		    Â  Unhook the alternator and do a battery only

  Â  flight.



  Yes, that is exactly what I am planning for the next flight. Additionally, the EIS is remotely mounted but it has a display. I intend to fly with a GoPro aimed at it to see if the CHT values that it displays match those on the EFIS. If there is simply a communication problem or some source of noise in the EFIS, then the EIS should be displaying the correct CHT values and not wildly fluctuating. 	


     Is there a downloadable installation

     manual for your EFIS?



 

   Bob . . .

ron228rj(at)gmail.com
Guest

Posted: Wed Aug 26, 2020 8:19 am Post subject: B&C SD-8 Alternator/Regulator

 	  Quote: 	
		  On Aug 26, 2020, at 10:31 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:



  Serial data are pretty robust with respect

    to noises . . . I'm pondering the possibility

    of a grounding issue for the analog inputs.

    Analog temperature data signals, whether thermocouple

    or RTC are small and the fact that the whole

    suite of measurements are flaky suggests

    something common to signal conditioning.

	


The interesting thing is that the bad values apply across all channels, including ones that arenâ€™t even hooked up, like cylinders 5 and 6. Another one is coolant temperature. It always should read 59 deg for no signal since it is not hooked up. My data recording at 5 Hz captured a single incidence of -32000 degF and then back to 59 until recording stopped. Values in the -32000 range have shown up on CHT channels and others as well. 

The manufacturer is mystified. I am collecting more data today, checking all ground connections, and then will probably ship it to them for testing tomorrow. 

Ron

ceengland7(at)gmail.com
Guest

Posted: Wed Aug 26, 2020 8:52 am Post subject: B&C SD-8 Alternator/Regulator

On Wed, Aug 26, 2020 at 11:25 AM Ron Springer <ron228rj(at)gmail.com (ron228rj(at)gmail.com)> wrote:



 	  Quote: 	
		  

 	  Quote: 	
		  On Aug 26, 2020, at 10:31 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



Â  Serial data are pretty robust with respect

 Â Â  to noises . . . I'm pondering the possibility

 Â Â  of a grounding issue for the analog inputs.

 Â Â  Analog temperature data signals, whether thermocouple

 Â Â  or RTC are small and the fact that the whole

 Â Â  suite of measurements are flaky suggests

 Â Â  something common to signal conditioning.

	


The interesting thing is that the bad values apply across all channels, including ones that arenâ€™t even hooked up, like cylinders 5 and 6. Another one is coolant temperature. It always should read 59 deg for no signal since it is not hooked up. My data recording at 5 Hz captured a single incidence of -32000 degF and then back to 59 until recording stopped. Values in the -32000 range have shown up on CHT channels and others as well.Â 

The manufacturer is mystified. I am collecting more data today, checking all ground connections, and then will probably ship it to them for testing tomorrow.Â 

Ron



	




I hate saying this out loud, but have you tried whacking the case to see if you can stimulate the glitches? IIRC, you said it only happens in flight, right? Vibration can generate all kinds of weird symptoms in electronics if there are intermittent connections involved.

Charlie

ron228rj(at)gmail.com
Guest

Posted: Wed Aug 26, 2020 9:13 am Post subject: B&C SD-8 Alternator/Regulator

No problem saying it. That is worth trying!



Sent from my iPhone



 	  Quote: 	
		  On Aug 26, 2020, at 1:00 PM, Charlie England <ceengland7(at)gmail.com> wrote:



ï»¿



On Wed, Aug 26, 2020 at 11:25 AM Ron Springer <ron228rj(at)gmail.com (ron228rj(at)gmail.com)> wrote:



 	  Quote: 	
		  

 	  Quote: 	
		  On Aug 26, 2020, at 10:31 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



  Serial data are pretty robust with respect

    to noises . . . I'm pondering the possibility

    of a grounding issue for the analog inputs.

    Analog temperature data signals, whether thermocouple

    or RTC are small and the fact that the whole

    suite of measurements are flaky suggests

    something common to signal conditioning.

	


The interesting thing is that the bad values apply across all channels, including ones that arenâ€™t even hooked up, like cylinders 5 and 6. Another one is coolant temperature. It always should read 59 deg for no signal since it is not hooked up. My data recording at 5 Hz captured a single incidence of -32000 degF and then back to 59 until recording stopped. Values in the -32000 range have shown up on CHT channels and others as well. 

The manufacturer is mystified. I am collecting more data today, checking all ground connections, and then will probably ship it to them for testing tomorrow. 

Ron



	




I hate saying this out loud, but have you tried whacking the case to see if you can stimulate the glitches? IIRC, you said it only happens in flight, right? Vibration can generate all kinds of weird symptoms in electronics if there are intermittent connections involved.

Charlie

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Aug 26, 2020 1:43 pm Post subject: B&C SD-8 Alternator/Regulator

 	  Quote: 	
		  

 I hate saying this out loud, but have you tried whacking the case to see if you can stimulate the glitches? IIRC, you said it only happens in flight, right? Vibration can generate all kinds of weird symptoms in electronics if there are intermittent connections involved.

 Charlie 	




   You're telling your age my friend . . . I'll bet you

   had real world experience with vacuum tube electronics!



 



 

   Bob . . .

ceengland7(at)gmail.com
Guest

Posted: Wed Aug 26, 2020 2:14 pm Post subject: B&C SD-8 Alternator/Regulator

On Wed, Aug 26, 2020 at 4:50 PM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



 	  Quote: 	
		     	  Quote: 	
		  

 I hate saying this out loud, but have you tried whacking the case to see if you can stimulate the glitches? IIRC, you said it only happens in flight, right? Vibration can generate all kinds of weird symptoms in electronics if there are intermittent connections involved.

 Charlie 	




 Â  You're telling your age my friend . . . I'll bet you

 Â  had real world experience with vacuum tube electronics!



 



 

 Â  Bob . . .

	




Uh...yep. Tube-top-thump was an essential troubleshooting tool; even the musicians knew that one. Still have a scar on my hand somewhere from touching the wrong (750V) terminal in the guts of a Marshall guitar amp I was repairing, some time in the mid 1970s. I've forgotten a lot of stuff; not that smell....Â 

But I've even seen solid state components that were shock-sensitive when they started going south.

Charlie

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Aug 26, 2020 2:30 pm Post subject: B&C SD-8 Alternator/Regulator

 	  Quote: 	
		  

 Uh...yep. Tube-top-thump was an essential troubleshooting tool; even the musicians knew that one. Still have a scar on my hand somewhere from touching the wrong (750V) terminal in the guts of a Marshall guitar amp I was repairing, some time in the mid 1970s. I've forgotten a lot of stuff; not that smell....Â 	




   Speaking of smells . . . the youngster's look

   at you incredulously when you assert that sticking

   your nose into the cabinet after removing the back

   was a powerful diagnostic tool.



   Power transformers, electrolytic caps, paper

   caps, plastic caps, resistors, flyback transformers,

   resistors, etc. all had their own characteristic

   odors when 'smoked'. Staring with overt symptoms

   one could be halfway to a diagnosis by simply sniffing

   as you pulled the back off the set.



   Not so much these days . . .



   



 

 

   Bob . . .

ron228rj(at)gmail.com
Guest

Posted: Wed Aug 26, 2020 3:32 pm Post subject: B&C SD-8 Alternator/Regulator

Just did a test flight and shot some video of the EIS to compare to the EFIS. I havenâ€™t even looked at it yet because I did something else for the first time. I shut off the magneto and everything got perfectly quiet on the EFIS, along with the noise that seems to be getting louder in my headset on each flight!



I never really focused on the magneto because it was brand new. But, let me tell you about the old mag. I hand prop my VariEze on the magneto only and suddenly I couldnâ€™t get it started any more. I suspected the mag was weak. I opened it to adjust the egap and the slot wasnâ€™t big enough to adjust it. Then I dug through the original builderâ€™s paperwork and learned it had 1100 hours on it and probably was never serviced. So, I just bought a new one. It would have been more obvious if I had flown the new mag immediately but I installed it and then decided to tear down the engine and do a bunch of other mods. 

I am guessing that if the wires are the problem, installing a new, much stronger magneto can make things a lot worse?

Ron



Sent from my iPhone



 	  Quote: 	
		  On Aug 26, 2020, at 6:36 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:



ï»¿   	  Quote: 	
		  

 Uh...yep. Tube-top-thump was an essential troubleshooting tool; even the musicians knew that one. Still have a scar on my hand somewhere from touching the wrong (750V) terminal in the guts of a Marshall guitar amp I was repairing, some time in the mid 1970s. I've forgotten a lot of stuff; not that smell....Ã‚ 	




   Speaking of smells . . . the youngster's look

   at you incredulously when you assert that sticking

   your nose into the cabinet after removing the back

   was a powerful diagnostic tool.



   Power transformers, electrolytic caps, paper

   caps, plastic caps, resistors, flyback transformers,

   resistors, etc. all had their own characteristic

   odors when 'smoked'. Staring with overt symptoms

   one could be halfway to a diagnosis by simply sniffing

   as you pulled the back off the set.



   Not so much these days . . .



   



 

 

   Bob . . .

ron228rj(at)gmail.com
Guest

Posted: Wed Aug 26, 2020 3:38 pm Post subject: B&C SD-8 Alternator/Regulator

I am still not sure why it only seems to occur in the air. More vibration? It shakes pretty good at full throttle on the ground too. The ground runs have primarily been done the VariEze nose on the ground. But, the plane is nonconductive. Could the proximity of the ground have an effect?



Ron



Sent from my iPhone



 	  Quote: 	
		  On Aug 26, 2020, at 7:28 PM, Ron Springer <ron228rj(at)gmail.com> wrote:



ï»¿Just did a test flight and shot some video of the EIS to compare to the EFIS. I havenâ€™t even looked at it yet because I did something else for the first time. I shut off the magneto and everything got perfectly quiet on the EFIS, along with the noise that seems to be getting louder in my headset on each flight!



I never really focused on the magneto because it was brand new. But, let me tell you about the old mag. I hand prop my VariEze on the magneto only and suddenly I couldnâ€™t get it started any more. I suspected the mag was weak. I opened it to adjust the egap and the slot wasnâ€™t big enough to adjust it. Then I dug through the original builderâ€™s paperwork and learned it had 1100 hours on it and probably was never serviced. So, I just bought a new one. It would have been more obvious if I had flown the new mag immediately but I installed it and then decided to tear down the engine and do a bunch of other mods. 

I am guessing that if the wires are the problem, installing a new, much stronger magneto can make things a lot worse?

Ron



Sent from my iPhone



 	  Quote: 	
		  On Aug 26, 2020, at 6:36 PM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:



ï»¿   	  Quote: 	
		  

 Uh...yep. Tube-top-thump was an essential troubleshooting tool; even the musicians knew that one. Still have a scar on my hand somewhere from touching the wrong (750V) terminal in the guts of a Marshall guitar amp I was repairing, some time in the mid 1970s. I've forgotten a lot of stuff; not that smell....Ã‚ 	




   Speaking of smells . . . the youngster's look

   at you incredulously when you assert that sticking

   your nose into the cabinet after removing the back

   was a powerful diagnostic tool.



   Power transformers, electrolytic caps, paper

   caps, plastic caps, resistors, flyback transformers,

   resistors, etc. all had their own characteristic

   odors when 'smoked'. Staring with overt symptoms

   one could be halfway to a diagnosis by simply sniffing

   as you pulled the back off the set.



   Not so much these days . . .



   



 

 

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Aug 26, 2020 4:15 pm Post subject: B&C SD-8 Alternator/Regulator

At 06:28 PM 8/26/2020, you wrote:

  	  Quote: 	
		  Just did a test flight and shot some video of the EIS to compare to the EFIS. I havenâ€™t even looked at it yet because I did something else for the first time. I shut off the magneto and everything got perfectly quiet on the EFIS, along with the noise that seems to be getting louder in my headset on each flight! 	




   Aha! One more flight test:



   Leave the mag wire totally unhooked at

   the engine end. Of course this leaves

   you an always-hot mag but the p-lead

   effects are now out of the diagnostic

   loop. 



   If the effect goes away, you're looking

   at p-lead; if it stays you're looking

   at plug wires.



 



 

   Bob . . .

kenryan

Joined: 20 Oct 2009
Posts: 424

Posted: Wed Aug 26, 2020 6:09 pm Post subject: B&C SD-8 Alternator/Regulator

I had a tv that would periodically just lose the picture and a very hard slap to the left side of the case would instantly bring it back. Sometimes it took two very hard slaps!



On Wed, Aug 26, 2020 at 1:50 PM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



 	  Quote: 	
		     	  Quote: 	
		  

 I hate saying this out loud, but have you tried whacking the case to see if you can stimulate the glitches? IIRC, you said it only happens in flight, right? Vibration can generate all kinds of weird symptoms in electronics if there are intermittent connections involved.

 Charlie 	




 Â  You're telling your age my friend . . . I'll bet you

 Â  had real world experience with vacuum tube electronics!



 



 

 Â  Bob . . .

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