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OVM-14 MkIII

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finn.lassen(at)verizon.ne
Guest

Posted: Thu Sep 21, 2023 5:56 am Post subject: OVM-14 MkIII

On 9/20/2023 10:47 PM, Robert L.       Nuckolls, III wrote:

     

      	  Quote: 	
		                At 12:35 PM 9/20/2023, you wrote:

               	  Quote: 	
		  Bob,

           

           I want to turn on an idiot light that indicates an           over-voltage trip           event.

           

           The attached quick-and-dirty schematic shows what I would like           to do,           however I have not seen a final schematic for your latest OVM,           so I'm           working on some assumptions. 	
       

       ï¿½ What you've described will work . . . but do you 

       ï¿½ NOT have a low voltage warning light? What would

       ï¿½ the ov light tell you that the lv light would not?

       

       

                

           ï¿½ Bob . . .

             ï¿½       	
     I would love to have an indication telling me why the       field breaker tripped. Over voltage or excessive field/voltage       regulator current?

       I'm still trying to figure out why my breaker sometimes pops when       pulling back to low RPMs. I had changed the alternator pulley to       prevent excessive RPMs and wear on the alternator, so it may well       be field over-current. On the other hand field current with       alternator stopped is 3.45A and appears to be next to nothing when       running at 3,000RPM and above. 5A breaker. Still working on data       logging to figure it out.

       

       Finn

neal.george(at)gmail.com
Guest

Posted: Thu Sep 21, 2023 6:13 am Post subject: OVM-14 MkIII

Unless the OV light has a latching function, will it not extinguish as soon as the crowbar trips the Field breaker?



Neal George

Sent from my iPhone

ï»¿

 	  Quote: 	
		   do you

 NOT have a low voltage warning light? What would

 the ov light tell you that the lv light would not?

 


	


An over-voltage light will tell the reason for low voltage.  There could be other reasons fir low voltage. 

I would save troubleshooting for when safely on the ground.  But some pilots might find an

over-voltage light helpful depending on the aircraft instrumentation and pilot workload and stress factor.



--------

Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 21, 2023 8:08 am Post subject: OVM-14 MkIII

At 07:09 AM 9/21/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>



 

 > do you

 > NOT have a low voltage warning light? What would

 > the ov light tell you that the lv light would not?

 > 



 An over-voltage light will tell the reason for low voltage. 	


     Assuming we subscribe to "aviate, navigate, communicate

     and leave tools in the hangar", then knowing why a

     low voltage condition exists is not useful while

     airborne. Once on the ground, a popped breaker is

     as profound as a light annunciating the obvious.



  	  Quote: 	
		  There could be other reasons fir low voltage. 	


     Sure 'nuf. The vast majority of low voltage

     conditions involve broken belts, broken

     wires, worn brushes. Fault on field supply

     line which would open the breaker and masquerade

     as an ov condition when in fact, no such

     condition exists. The PTT feature 

     helps resolve the paradox.



  	  Quote: 	
		  I would save troubleshooting for when safely on the ground.  But some pilots might find an 

 over-voltage light helpful depending on the aircraft instrumentation and pilot workload and stress factor. 	


     I suggest that info is of no value:



     LOW VOLTS LIGHT - ON

     MAIN ALTERNATOR - OFF

     AUX ALTERNATOR (if installed) - ON

     PLAN-B LOAD MANAGEMENT - ACCOMPLISHED

     LANDING - AS SOON AS PRACTICAL

     TOOLBOX - OPEN



     Reversion to Plan-B is consistent irrespective

     of root cause, i.e. no difference in work-load.



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 21, 2023 8:24 am Post subject: OVM-14 MkIII

 	  Quote: 	
		  I would love to have an indication telling me why the field breaker tripped. Over voltage or excessive field/voltage

 regulator current? 	


   Having an annunciator call out OPEN BREAKER doesn't

   help resolve the issue.



  	  Quote: 	
		  I'm still trying to figure out why my breaker sometimes pops when pulling back to low

 RPMs. I had changed the alternator pulley to prevent excessive RPMs and wear on the

 alternator 	


   Were you experiencing alternator failures or

   excessive wear with a diagnosis of 'turning

   too fast'?



   Check with the field service gurus at B&C

   to inquire as to their experience over decades

   and thousands of alternator installations.

   How often do alternators fail due to

   mechanical wear?



   About 30 years ago, Van's customer service

   advice and their design policy for alternators

   they supplied called for a special, oversized

   pulley to slow down alternator to forestall

   'excessive stress'.



   In fact, slowing the alternator down only

   increases field current and reduces cooling

   airflow from internal fans. Bearings and

   brushes are not significantly affected by

   increased operating speeds.



  	  Quote: 	
		  . . . so it may well be field over-current. 	


   So how many other choices do you have? Trips occur

   only at low rpm? OV conditions can present

   at ANY rpm. Did this condition exist before

   you increased pulley size?



  	  Quote: 	
		  On the other hand field current with alternator stopped

 is 3.45A and appears to be next to nothing when running at

 3,000RPM and above. 5A breaker. Still working on data

 logging to figure it out. 	


   I would start by replacing the breaker . . .

   your breaker may be 'soft'. Maybe upsize to

   7A. Better yet, put the smaller pulley back on.



 

 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 21, 2023 8:28 am Post subject: OVM-14 MkIII

At 09:12 AM 9/21/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: Neal George <neal.george(at)gmail.com>



 Unless the OV light has a latching function, will it not extinguish as soon as the crowbar trips the Field breaker?



 Neal George 	


   In this case, the light was essentially

   across an open breaker. I.e. it would

   annunciate a 'breaker open' condition

   irrespective of root cause.



   Kinda like those whizzy fuses with

   built in LEDs that illuminate if the

   fuse is blown.



   BTW Neal, I got my gmail bouncing issues

   resolved with my email server. I think

   I may have some messages intended for you

   that were never delivered. I'll check

   to see if we have any significant

   issues 'hung up'.



 

 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

jluckey(at)pacbell.net
Guest

Posted: Thu Sep 21, 2023 8:38 am Post subject: OVM-14 MkIII

Neal - yes, latching is essential and my sketch assumes that it is possible.  (and I believe that Bob confirmed that)

Joe - agree with what you said.

Off the top of my head, the alternator field breaker could be tripped for the following reasons:

1. Wiring fault

2. Regulator fault/fail

3. Breaker failure

4. Actual/legitimate over voltage event

5. OVM fault

If we get some kind of indication that the tripped field breaker is due to some action taken by the OVM then that additional info will aid in our diagnosis. 

Anecdotally, I just saw a thread on another forum where and aging circuit breaker was nuisance tripping.  There was quite a bit of trouble-shooting and back and fourth.  After a week or two the breaker was replaced and the problem was fixed.

Another thought, the early adopters of Bob's new OVM will essentially be beta testers. If the OVM is a little "twitchy" and nuisance trips frequently, having an idiot light would immediately confirm that the OVM caused the breaker to trip. (It would not tell you what's wrong with the OVM but just knowing that it is the cause would be extremely helpful.)

I just read further down this thread.  To clarify the requirements: The idiot light must indicate that the OVM "fired", not just that the field breaker is open.

-Jeff

                                                                    On Thursday, September 21, 2023 at 09:15:49 AM PDT, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:                 

                   At 07:09 AM 9/21/2023, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com>

 > do you

 > NOT have a low voltage warning light? What would

 > the ov light tell you that the lv light would not?

 > 

 An over-voltage light will tell the reason for low voltage. 	

     Assuming we subscribe to "aviate, navigate, communicate

     and leave tools in the hangar", then knowing why a

     low voltage condition exists is not useful while

     airborne. Once on the ground, a popped breaker is

     as profound as a light annunciating the obvious.

  	  Quote: 	
		  There could be other reasons fir low voltage. 	

     Sure 'nuf. The vast majority of low voltage

     conditions involve broken belts, broken

     wires, worn brushes. Fault on field supply

     line which would open the breaker and masquerade

     as an ov condition when in fact, no such

     condition exists. The PTT feature 

     helps resolve the paradox.

  	  Quote: 	
		  I would save troubleshooting for when safely on the ground.  But some pilots might find an 

 over-voltage light helpful depending on the aircraft instrumentation and pilot workload and stress factor. 	

     I suggest that info is of no value:

     LOW VOLTS LIGHT - ON

     MAIN ALTERNATOR - OFF

     AUX ALTERNATOR (if installed) - ON

     PLAN-B LOAD MANAGEMENT - ACCOMPLISHED

     LANDING - AS SOON AS PRACTICAL

     TOOLBOX - OPEN

     Reversion to Plan-B is consistent irrespective

     of root cause, i.e. no difference in work-load.

    Bob . . .

                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

finn.lassen(at)verizon.ne
Guest

Posted: Thu Sep 21, 2023 10:09 am Post subject: OVM-14 MkIII

On 9/21/2023 12:24 PM, Robert L.       Nuckolls, III wrote:

     

      	  Quote: 	
		                 	  Quote: 	
		  I           would love to           have an indication telling me why the field breaker tripped.           Over voltage           or excessive field/voltage

           regulator current? 	
       

         ï¿½ Having an annunciator call out OPEN BREAKER doesn't

         ï¿½ help resolve the issue.

         

          	  Quote: 	
		  I'm still trying to           figure out           why my breaker sometimes pops when pulling back to low

           RPMs. I had changed the alternator pulley to prevent excessive           RPMs and           wear on the

           alternator 	
         

         ï¿½ Were you experiencing alternator failures or

         ï¿½ excessive wear with a diagnosis of 'turning

         ï¿½ too fast'?

       	
     No, purely a preventive measure.

      	  Quote: 	
		  

         ï¿½ Check with the field service gurus at B&C

         ï¿½ to inquire as to their experience over decades

         ï¿½ and thousands of alternator installations.

         ï¿½ How often do alternators fail due to

         ï¿½ mechanical wear?

         

         ï¿½ About 30 years ago, Van's customer service

         ï¿½ advice and their design policy for alternators

         ï¿½ they supplied called for a special, oversized

         ï¿½ pulley to slow down alternator to forestall

         ï¿½ 'excessive stress'.

         

         ï¿½ In fact, slowing the alternator down only

         ï¿½ increases field current and reduces cooling

         ï¿½ airflow from internal fans. Bearings and

         ï¿½ brushes are not significantly affected by

         ï¿½ increased operating speeds.

       	
     In my case (Madza 13-B Renesis), cruise is typically       5,000 to 6,000 RPM. So it seems reasonable to slow down the       alternator to that speed rather than maybe twice that.

      	  Quote: 	
		  

          	  Quote: 	
		  . . . so it may           well be field           over-current. 	
         

         ï¿½ So how many other choices do you have? Trips occur

         ï¿½ only at low rpm? 	
     Have seen it happen around 3,000 RPM but not as       frequent as when quickly pulling back to 1,700 or so. Just need to       rule out other possible causes such a intermittent shorts at       certain RPMs (chafing at certain vibrations). Got 85 hours on the       Hobbs, probably another 30 hours on engine in the airframe.

      	  Quote: 	
		  OV conditions can present

         ï¿½ at ANY rpm. Did this condition exist before

         ï¿½ you increased pulley size?

       	
     Not that I recall. Certainly not as frequent.

      	  Quote: 	
		  

          	  Quote: 	
		  On the other hand           field current           with alternator stopped

           is 3.45A and appears to be next to nothing when running at

           3,000RPM and above. 5A breaker. Still working on data

           logging to figure it out. 	
         

         ï¿½ I would start by replacing the breaker . . .

         ï¿½ your breaker may be 'soft'. Maybe upsize to

         ï¿½ 7A. Better yet, put the smaller pulley back on.

       	
     Already replaced the breaker. New rectifier bridge       and regulator in alternator.

       

       Hate the idea of disconnecting the OV crowbar.

       

       My plan is to improve data logging to detect the real cause. 

       

       Very recently I installed four current sensors (Kitplane article       May 17, 2019) and log their output every second:ï¿½ Engine bus, Main       bus, Alternator field and Alternator output. They are not what I       hoped for. Didn't realize how sensitive they are to other magnetic       fields. Mounted near battery a few inches from alternator. I may       start a new thread with my experience with them, if that would be       of general interest.

       

       Finn

           	  Quote: 	
		  

         

                

           ï¿½ Bob . . .

           

           ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½           //// 

           ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½           (o o) 

           ï¿½ï¿½ ===========o00o=(_)=o00o========= 

           ï¿½ï¿½ < Go ahead, make my day . . .ï¿½ï¿½ > 

           ï¿½ï¿½ < show me where I'm wrong.ï¿½ï¿½ï¿½ï¿½ï¿½           > 

           ï¿½ï¿½ =================================

           ï¿½

           ï¿½ï¿½ In the interest of creative evolution

           ï¿½ï¿½ of the-best-we-know-how-to-do based

           ï¿½ï¿½ on physics and good practice.

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 21, 2023 1:28 pm Post subject: OVM-14 MkIII

 	  Quote: 	
		  My plan is to improve data logging to detect the real cause. 



 Very recently I installed four current sensors (Kitplane article May 17, 2019) and log their output every second:ï¿½ Engine bus, Main bus, Alternator field and Alternator output. They are not what I hoped for. Didn't realize how sensitive they are to other magnetic fields. Mounted near battery a few inches from alternator. I may start a new thread with my experience with them, if that would be of general interest. 	


   I downloaded May 2019 Kitplanes and couldn't find the article.

   Can you refine the source citation?



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 21, 2023 4:09 pm Post subject: OVM-14 MkIII

At 11:38 AM 9/21/2023, you wrote:

  	  Quote: 	
		  Neal - yes, latching is essential and my sketch assumes that it is possible.  (and I believe that Bob confirmed that)

 	


   I'm lost . . . with the crowbar OV management

   system, an OV event triggers a low resistance

   load downstream of the alternator field breaker

   forcing it to open thus depriving the alternator

   of field excitation.



   This even is inherently latching . . . the breaker

   is not going to close itself. A light wired across

   the open breaker would illuminate until the

   breaker is re-closed.



   I'm not seeing value in adding circuitry to

   sense/latch based on the ov event.



 

 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

finn.lassen(at)verizon.ne
Guest

Posted: Thu Sep 21, 2023 4:28 pm Post subject: OVM-14 MkIII

On 9/21/2023 5:28 PM, Robert L.       Nuckolls, III wrote:

     

      	  Quote: 	
		                 	  Quote: 	
		  My           plan is to           improve data logging to detect the real cause. 

           

           Very recently I installed four current sensors (Kitplane           article May 17,           2019) and log their output every second:ï¿½ Engine bus, Main           bus,           Alternator field and Alternator output. They are not what I           hoped for.           Didn't realize how sensitive they are to other magnetic           fields. Mounted           near battery a few inches from alternator. I may start a new           thread with           my experience with them, if that would be of general           interest. 	
       

       ï¿½ I downloaded May 2019 Kitplanes and couldn't find the       article.

       ï¿½ Can you refine the source citation?

       

                

           ï¿½ Bob . . .

             

                  	
     "Hall of Fame" article by Jim Weirï¿½ May 17,         2019. In Kitplanes July 2019 mag.

         

         Attached my version. The four outputs go to analog inputs on an         Arduino Mega 2590 and a SDRAM shield for logging. Not shown the         hall sensors also fed by the Mega 2590's 5V power output. But         shouldn't I start a new thread for this?

         

         Finn

CurrentSensors.pdf

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Download

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CurrentSensors.pdf

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Downloaded:

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jluckey(at)pacbell.net
Guest

Posted: Thu Sep 21, 2023 5:11 pm Post subject: OVM-14 MkIII

I posted this under a new title but I should have posted in this thread...





Simple "OVM has Fired" Idiot Light

Here's a circuit that does the trick using a $2 latching relay.  Please check it for errors.  I just corrected a few and re-sent the latest version to Google Drive.



See OVMTripIndicator_SA.pdf

OVMTripIndicator_SA.pdf



                  

                                                                    On Thursday, September 21, 2023 at 05:15:46 PM PDT, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:                 

                 



                 



                   At 11:38 AM 9/21/2023, you wrote:

  	  Quote: 	
		  Neal - yes, latching is essential and my sketch assumes that it is possible.  (and I believe that Bob confirmed that)

 	


   I'm lost . . . with the crowbar OV management

   system, an OV event triggers a low resistance

   load downstream of the alternator field breaker

   forcing it to open thus depriving the alternator

   of field excitation.



   This even is inherently latching . . . the breaker

   is not going to close itself. A light wired across

   the open breaker would illuminate until the

   breaker is re-closed.



   I'm not seeing value in adding circuitry to

   sense/latch based on the ov event.



 

 

    Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

neal.george(at)gmail.com
Guest

Posted: Thu Sep 21, 2023 6:23 pm Post subject: OVM-14 MkIII

Just send me back to my corner and crayon snacks 😊.

 

I looked at the proposed circuit, but didnâ€™t study it, and in not studying, didnâ€™t grok it â€“ I can look at the simplest of schematics for an eternity and still not get it.Â  Not pairing the words with the proposed schematic, I imagined one light, multiple functions (I seem to remember a device (LR3x, maybe?) Â that could set a lamp ON for over-voltage, blinking for low voltage).

 

Mea Culpaâ€¦ didnâ€™t mean to roll a grenade.

 

Neal



 

At 11:38 AM 9/21/2023, you wrote:



 	  Quote: 	
		  

Neal - yes, latching is essential and my sketch assumes that it is possible.  (and I believe that Bob confirmed that) 	




  I'm lost . . . with the crowbar OV management

  system, an OV event triggers a low resistance

  load downstream of the alternator field breaker

  forcing it to open thus depriving the alternator

  of field excitation.



  This even is inherently latching . . . the breaker

  is not going to close itself. A light wired across

  the open breaker would illuminate until the

  breaker is re-closed.



  I'm not seeing value in adding circuitry to

  sense/latch based on the ov event.





  Bob . . .



                   //// 

                  (o o) 

   ===========o00o=(_)=o00o========= 

   < Go ahead, make my day . . .   > 

   < show me where I'm wrong.      > 

   =================================

 

   In the interest of creative evolution

   of the-best-we-know-how-to-do based

   on physics and good practice.

jluckey(at)pacbell.net
Guest

Posted: Fri Sep 22, 2023 10:22 am Post subject: OVM-14 MkIII

Crayons?  I like crayons.  I do some of my best work with crayons ... and snacks?  Who doesn't like snacks?

-Jeff



                  

                                                                    On Thursday, September 21, 2023 at 07:29:44 PM PDT, Neal George <neal.george(at)gmail.com> wrote:                 

                 



                 



                 

Just send me back to my corner and crayon snacks ðŸ˜Š.

  

I looked at the proposed circuit, but didnâ€™t study it, and in not studying, didnâ€™t grok it â€“ I can look at the simplest of schematics for an eternity and still not get it.  Not pairing the words with the proposed schematic, I imagined one light, multiple functions (I seem to remember a device (LR3x, maybe?)  that could set a lamp ON for over-voltage, blinking for low voltage).

  

Mea Culpaâ€¦ didnâ€™t mean to roll a grenade.

  

Neal



  

At 11:38 AM 9/21/2023, you wrote: 	  Quote: 	
		  

Neal - yes, latching is essential and my sketch assumes that it is possible.  (and I believe that Bob confirmed that) 	


  I'm lost . . . with the crowbar OV management  system, an OV event triggers a low resistance  load downstream of the alternator field breaker  forcing it to open thus depriving the alternator  of field excitation.  This even is inherently latching . . . the breaker  is not going to close itself. A light wired across  the open breaker would illuminate until the  breaker is re-closed.  I'm not seeing value in adding circuitry to  sense/latch based on the ov event.

  Bob . . .                   ////                   (o o)    ===========o00o=(_)=o00o=========    < Go ahead, make my day . . .   >    < show me where I'm wrong.      >    ========    In the interest of creative evolution   of the-best-we-know-how-to-do based   on physics and good practice.

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Sep 23, 2023 3:52 pm Post subject: OVM-14 MkIII

 	  Quote: 	
		  I looked at the proposed circuit, but didnâ€™t study it, and in not studying, didnâ€™t grok it – I can look at the simplest of scchematics for an eternity and still not get it.Â  Not pairing the words with the proposed schematic, I imagined one light, multiple functions (I seem to remember a device (LR3x, maybe?) Â that could set a lamp ON for over-voltage, blinking for low voltage). 	


    Does it really do that? All the data I have

    here says that light is ALWAYS flashed and

    ONLY in response to a detected low voltage.



    Due to the nature of LR3 crowbar ov protection,

    an OV event is followed milliseconds later

    by a LV event. There would not be any time

    to sense, display and perceive an OV condition.



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

neal.george(at)gmail.com
Guest

Posted: Sun Sep 24, 2023 1:13 pm Post subject: OVM-14 MkIII

Does it really do that? 

 

Probably not.Â  I may have mentioned that I have an unreliable memory.



   Due to the nature of LR3 crowbar ov protection,

   an OV event is followed milliseconds later

   by a LV event. There would not be any time

   to sense, display and perceive an OV condition.

 

That behavior I /do/ remember, from years of you repeating it (so that we dullards might learn it).Â  And thatâ€™s what spurred my comment â€“ the way I understood the OV event in a Z-figure environment, OV would occur and be terminated before the lamp could heat up; the chances of pilot notice are exceedingly small.Â  Other annunciations would be necessary to indicate that an OV event preceded the LV condition.

Neal

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Sep 25, 2023 9:50 am Post subject: OVM-14 MkIII

 	  Quote: 	
		     Due to the nature of LR3 crowbar ov protection,

    an OV event is followed milliseconds later

    by a LV event. There would not be any time

    to sense, display and perceive an OV condition.



  



 That behavior I /do/ remember, from years of you repeating it (so that we dullards might learn it).Â  And thatâ€™s what spurred my comment – the way I understood the OV event in a Z-figure environment, OV would occur and be terminated before the lamp could heat up; the chances of pilot notice are exceedingly small.Â  Other annunciations would be necessary to indicate that an OV event preceded the LV condition.



 Neal 	


   Exactly so my friend. Having been both designer

   and producer of ov management components in both TC

   and experimental markets for decades there was only ONE

   device conceived that featured both OV and LV

   warning. I designed it for B&C in response to

   some demand from the ultralight community. Seems

   it is still offered.



  https://bandc.com/product/over-under-voltage-sensor/



   In this instance, potential for a runaway

   alternator to quickly drive bus voltage to

   dangerous heights was small . .  the alternator

   would struggle for some time to push the battery

   above 16.0v



   Further, these airplanes almost never had

   panel mounted, bus drive avionics . . . radios

   were hand-held. I wonder how many of these

   got installed on more complex airplanes . . .

   not a problem. But if the alternator is

   judiciously configured, the OV warning

   light would never be noticed.



 

   Bob . . .



                    //// 

                   (o o) 

    ===========o00o=(_)=o00o========= 

    < Go ahead, make my day . . .   > 

    < show me where I'm wrong.      > 

    =================================

  

    In the interest of creative evolution

    of the-best-we-know-how-to-do based

    on physics and good practice.

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