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n744bh(at)bellsouth.net
Guest

Posted: Fri Jul 20, 2012 12:04 pm Post subject: troubleshooting help needed

Here's the problem that has me scratching my  head.  I have a Glasair Super 2 that's been flying with no problems for  over 100 hours.  The electric system is Z 11, 14 volt.  The engine is  a Lycoming IO360 and the alternator is the one that came with the engine and of  Chrysler origin for aircraft use.  I'm told that they are fairly  bulletproof.  It was completely overhauled before I started flying.   The voltage regulator is a B & C LR3C.

  

 So here's the problem which has popped up in the  last 15 hours or so.  When I'm flying at cruise power, or even idling, the  voltage wanders up and down from 14.4v to slightly less than 13v.  It does  go down enough that my Garmin Aera 796 will drop off of ships power and go to  it's internal battery.  This would indicate to me that this is not a  problem with the voltmeter. This does not seem to have any measurable  cycle.  The amps stay constant at about 16 amps.  When I've had the  plane flying I've tried turning off equipment one at a time to see if that might  have any effect...it didn't.

  

 I've checked my connections for any corrosion and  everything looks good and tight, including the alternator belt.   The next  thing I'm going to do is run the B&C troubleshooting checklist but I thought  I would put this out for the list to see if anyone has any ideas that I haven't  thought of that I might check.  I personally suspect the LR3C but the folks  at B&C have their doubts.  So what y'all think?

  

 Bill

 Glasair SIIS-FT

  

  

   [quote][b]

bbradburry(at)bellsouth.n
Guest

Posted: Fri Jul 20, 2012 12:10 pm Post subject: troubleshooting help needed

Bill,  

I am having a similar problem with my Lancair.  The voltage seems to float up and down about a half volt and I have had problems with the transponder shutting down and the moving map resets.  I hope my problem is your problem and someone has a solution.  

   

Bill B  

         

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Bill Hibbing

 Sent: Friday, July 20, 2012 4:02 PM

 To: aeroelectric-list(at)matronics.com

 Subject: AeroElectric-List: troubleshooting help needed  

  

     

Here's the problem that has me scratching my head.  I have a Glasair Super 2 that's been flying with no problems for over 100 hours.  The electric system is Z 11, 14 volt.  The engine is a Lycoming IO360 and the alternator is the one that came with the engine and of Chrysler origin for aircraft use.  I'm told that they are fairly bulletproof.  It was completely overhauled before I started flying.  The voltage regulator is a B & C LR3C.  

    

   

    

So here's the problem which has popped up in the last 15 hours or so.  When I'm flying at cruise power, or even idling, the voltage wanders up and down from 14.4v to slightly less than 13v.  It does go down enough that my Garmin Aera 796 will drop off of ships power and go to it's internal battery.  This would indicate to me that this is not a problem with the voltmeter. This does not seem to have any measurable cycle.  The amps stay constant at about 16 amps.  When I've had the plane flying I've tried turning off equipment one at a time to see if that might have any effect...it didn't.  

    

   

    

I've checked my connections for any corrosion and everything looks good and tight, including the alternator belt.   The next thing I'm going to do is run the B&C troubleshooting checklist but I thought I would put this out for the list to see if anyone has any ideas that I haven't thought of that I might check.  I personally suspect the LR3C but the folks at B&C have their doubts.  So what y'all think?  

    

   

    

Bill  

    

Glasair SIIS-FT  

    

   

    

   

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nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jul 20, 2012 5:00 pm Post subject: troubleshooting help needed

At 03:02 PM 7/20/2012, you wrote:

 Here's the problem that has me scratching my head.  I have a Glasair Super 2 that's been flying with no problems for over 100 hours.  The electric system is Z 11, 14 volt.  The engine is a Lycoming IO360 and the alternator is the one that came with the engine and of Chrysler origin for aircraft use.  I'm told that they are fairly bulletproof.  It was completely overhauled before I started flying.  The voltage regulator is a B & C LR3C.

  

 So here's the problem which has popped up in the last 15 hours or so.  When I'm flying at cruise power, or even idling, the voltage wanders up and down from 14.4v to slightly less than 13v.  It does go down enough that my Garmin Aera 796 will drop off of ships power and go to it's internal battery.  This would indicate to me that this is not a problem with the voltmeter. This does not seem to have any measurable cycle.  The amps stay constant at about 16 amps.  When I've had the plane flying I've tried turning off equipment one at a time to see if that might have any effect...it didn't.

  

 I've checked my connections for any corrosion and everything looks good and tight, including the alternator belt.   The next thing I'm going to do is run the B&C troubleshooting checklist but I thought I would put this out for the list to see if anyone has any ideas that I haven't thought of that I might check.  I personally suspect the LR3C but the folks at B&C have their doubts.  So what y'all think?



     You need to bring three wires into the cockpit from

     the regulator. One that is attached to the field output

     terminal (4), another to ov-sense input (3) and a third

     to ground (7).



 [img]cid:.0[/img]



 



     You need to watch and record the voltage reading between

     ground (7) and field (4) when the alternator is operating

     normally at minimum system loads and maximum system loads.



     Then move your test voltmeter to read voltage between ground

     (7) and ov-sense (3). Repeat the min/max loads experiment

     and compare the readings on the test voltmeter and any

     panel displays for bus voltage.



     Then when the alternator is mis-behaving under any normal

     operating load, does the field voltage go UP as the

     bus voltage indications on the panel go down . . . or

     vice-versa? Also, during misbehavior notice if there

     is any deviation from ov-sense readings you acquired

     earlier and panel displayed voltage readings.



     If the alternator is working properly, Field and Bus voltage

     should go up and down together in response to output

     from the regulator. 



     If they are out of sync . . . then the alternator is bad

     (probably failing brushes). If they go up and down together,

     then move your test meter.



     If they do go up and down together, then turn your attention

     to the difference between panel voltage display and test

     meter. Are the differences markedly dissimilar from when the

     alternator was working?



     This exercise in data gathering allows one to deduce

     whether the problem lies in the alternator, regulator

     or ship's wiring.



 

 

   Bob . . .

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JLuckey(at)pacbell.net
Guest

Posted: Fri Jul 20, 2012 5:34 pm Post subject: troubleshooting help needed

See my question inserted about 3/4 way down the page…  

   

   

-Jeff Luckey        

  

From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls, III

 Sent: Friday, July 20, 2012 17:59

 To: aeroelectric-list(at)matronics.com

 Subject: Re: AeroElectric-List: troubleshooting help needed  

  

   

At 03:02 PM 7/20/2012, you wrote:

 Here's the problem that has me scratching my head.  I have a Glasair Super 2 that's been flying with no problems for over 100 hours.  The electric system is Z 11, 14 volt.  The engine is a Lycoming IO360 and the alternator is the one that came with the engine and of Chrysler origin for aircraft use.  I'm told that they are fairly bulletproof.  It was completely overhauled before I started flying.  The voltage regulator is a B & C LR3C.

  

 So here's the problem which has popped up in the last 15 hours or so.  When I'm flying at cruise power, or even idling, the voltage wanders up and down from 14.4v to slightly less than 13v.  It does go down enough that my Garmin Aera 796 will drop off of ships power and go to it's internal battery.  This would indicate to me that this is not a problem with the voltmeter. This does not seem to have any measurable cycle.  The amps stay constant at about 16 amps.  When I've had the plane flying I've tried turning off equipment one at a time to see if that might have any effect...it didn't.

  

 I've checked my connections for any corrosion and everything looks good and tight, including the alternator belt.   The next thing I'm going to do is run the B&C troubleshooting checklist but I thought I would put this out for the list to see if anyone has any ideas that I haven't thought of that I might check.  I personally suspect the LR3C but the folks at B&C have their doubts.  So what y'all think?

 

     You need to bring three wires into the cockpit from

     the regulator. One that is attached to the field output

     terminal (4), another to ov-sense input (3) and a third

     to ground (7).

 

 [img]cid:image001.jpg(at)01CD66A5.BF83DF20[/img]

 

 

 

     You need to watch and record the voltage reading between

     ground (7) and field (4) when the alternator is operating

     normally at minimum system loads and maximum system loads.

 

     Then move your test voltmeter to read voltage between ground

     (7) and ov-sense (3). Repeat the min/max loads experiment

     and compare the readings on the test voltmeter and any

     panel displays for bus voltage.

 

     Then when the alternator is mis-behaving under any normal

     operating load, does the field voltage go UP as the

     bus voltage indications on the panel go down . . . or

     vice-versa? Also, during misbehavior notice if there

     is any deviation from ov-sense readings you acquired

     earlier and panel displayed voltage readings.

 

     If the alternator is working properly, Field and Bus voltage

     should go up and down together in response to output

     from the regulator.   

   

[Luckey]   

Bob, is that correct - shouldn’t Field & Bus voltage oppose each other?  

i.e. as Bus voltage goes up, Field current should go down?  



 

     If they are out of sync . . . then the alternator is bad

     (probably failing brushes). If they go up and down together,

     then move your test meter.

 

     If they do go up and down together, then turn your attention

     to the difference between panel voltage display and test

     meter. Are the differences markedly dissimilar from when the

     alternator was working?

 

     This exercise in data gathering allows one to deduce

     whether the problem lies in the alternator, regulator

     or ship's wiring.

 

 

 

     

  Bob . . .

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nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jul 21, 2012 5:46 am Post subject: troubleshooting help needed

At 03:10 PM 7/20/2012, you wrote:

  	  Quote: 	
		   Bill,

 I am having a similar problem with my Lancair.  The voltage seems to float up and down about a half volt and I have had problems with the transponder shutting down and the moving map resets.  I hope my problem is your problem and someone has a solution.

  

 Bill B

  	


   If a .5 volt excursion is causing your electro-whizzies

   to misbehave, there's something else going on.



   While it's viscerally satisfying to see a bus voltage reading

   stay locked down to within a tenth of a volt of the

   set point, having it vary by 1/2 volt under repeatable

   conditions should not be an operational issue.



   Your bus voltage should fly somewhere north of 14.0

   volts . . . 14.2 was the 'sweet spot' when I worked

   at Cessna . . . 14.6 to as much as 15.0 volts seems

   to show up in contemporary automotive products.



   But 14.0 is the operating floor for making sure

   that a battery gets topped off a short time

   after takeoff.



   If your transponder is qualified for use in a

   type certficated airplane, it should operate without

   complaint down to end-of-battery-life voltage levels

   on the order of 11.0 volts. The moving map should

   be similarly qualified. For these devices to complain

   in concert suggests an intermittent condition that

   drops to levels much below your panel displays for

   bus voltage . . . a voltage level below battery

   supply voltage even. Loose connection?



 

 

   Bob . . .    [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Sat Jul 21, 2012 6:27 am Post subject: troubleshooting help needed

At 08:33 PM 7/20/2012, you wrote:



[Luckey]

Bob, is that correct - shouldn't Field & Bus voltage oppose each other?

i.e. as Bus voltage goes up, Field current should go down?



    It depends on what is being held constant and what

    is being adjusted.



    If SYSTEM LOAD is the variable, then yes . . . the

    REGULATOR senses an INCREASE in bus voltage and

    reacts by REDUCING field voltage.



    In this instance, we're observing changes in

    system performance while the load is constant.

    If the field voltage rises in concert with the

    bus voltage, then the regulator is commanding

    that rise due to internal failure or mis-information

    in the voltage sense path and the alternator

    is performing normally.



    If the bus voltage falls while the field voltage

    rises, then the regulator is flogging a crippled

    alternator without success.



   Bob . . .

n744bh(at)bellsouth.net
Guest

Posted: Thu Jul 26, 2012 7:15 pm Post subject: troubleshooting help needed

OK, here's an update on what I've found without the engine running and using 

the B&C LR3C troubleshooting checklist.



Step one gave me zero ohms resistance from the battery (-) to LR3C pin 7 and 

the same from the battery (-) to the engine case.



Step two gave me a battery bus voltage of 12.64v and a pin 3 voltage of 

12.62v.



Step three gave me a pin 6 voltage of 12.20, well within the 0.5v tolerance. 

So far so good.



Step four gave me a pin 4 voltage of 11.20v, well within the desired range.



Step five.  Here's where the fun begins.  I measured the voltage at the 

field terminal and it was zero.  Thinking that there may be a continuity 

problem I pulled the alternator field lead off the alternator and checked 

again...no voltage.  I turned off the power and checked the continuity and 

found it was good.  I also checked the alternator field resistance and it 

came in at 30.6 ohms.



So now I think I may have some sort of a problem here so I hooked everything 

back up and went back to step 4 and checked pin 4 again.  This time it was 

1.73 volts at both pin 4 and at the alternator field terminal.



The folks at B&C are at Oshkosh right now so getting hold of them might be 

difficult but maybe Bob can weigh in again on this one.



Bill

Glasair SIIS-FT

---

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jul 27, 2012 8:14 am Post subject: troubleshooting help needed

Your original squawk:



          When I'm flying at cruise power, or even idling, the voltage wanders up and down

         from 14.4v to slightly less than 13v.  It does go down enough that my Garmin

         Aera 796 will drop off of ships power and go to it's internal battery.  This would

         indicate to me that this is not a problem with the voltmeter. This does not seem

         to have any measurable cycle.  The amps stay constant at about 16 amps.

         When I've had the plane flying I've tried turning off equipment one at a time to

         see if that might have any effect...it didn't.

  

         So now I think I may have some sort of a problem

         here so I hooked everything back up and went back

         to step 4 and checked pin 4 again.  This time it

         was 1.73 volts at both pin 4 and at the alternator

         field terminal.



 You didn't tell us where your ammeter was connected . . .

 in other words, what current does it measure?



 The fact that your bus voltage falls so low (13.0 or below)

 suggests the alternator is going off line completely and that

 the bus voltage is falling to battery delivery voltage.



 Your narrative also suggests that your ammeter is looking at

 ship's loads and not alternator output which would explain

 the relatively constant ammeter reading.



  

         So now I think I may have some sort of a problem

         here so I hooked everything back up and went back

         to step 4 and checked pin 4 again.  This time it

         was 1.73 volts at both pin 4 and at the alternator

         field terminal.



 This is consistent with an intermittent disconnect of

 alternator field supply which. If the voltage at pin 4

 ever drops so low while pin 6 and 3 are at battery

 voltage points to failure within the regulator. Suggest

 you arrange to return it to B&C for inspection/repair.



 

   Bob . . .    [quote][b]

n744bh(at)bellsouth.net
Guest

Posted: Fri Jul 27, 2012 8:47 am Post subject: troubleshooting help needed

Thanks Bob, 

  

 That's about what I was thinking also.  I was  hoping that I would find the alternator was the problem as it's a heck of a lot  easier to change.  Another question for you...I currently have the LR3C  mounted on the cabin side of the firewall.  Do you see any problem with  relocating it to the engine side of the firewall?  As long as I have to  take it out, a real PITA, I thought I might change the location to a location  that is easier to work on it in the case of another failure.  Thanks,  

  

 Bill

 [quote] 

        So    now I think I may have some sort of a    problem

        here    so I hooked everything back up and went    back

        to step    4 and checked pin 4 again.  This time    it

        was 1.73    volts at both pin 4 and at the    alternator

        field    terminal.



This is consistent with an intermittent disconnect    of

alternator field supply which. If the voltage at pin 4

ever drops so    low while pin 6 and 3 are at battery

voltage points to failure within the    regulator. Suggest

you arrange to return it to B&C for    inspection/repair.



   

  Bob . . .    

  	  Quote: 	
		  



href="http://www.matronics.com/Navigator?AeroElectric-List">http://www.matronics.com/Navigator?AeroElectric-List

href="http://forums.matronics.com">http://forums.matronics.com

href="http://www.matronics.com/contribution">http://www.matronics.com/c

	
   

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ceengland7(at)gmail.com
Guest

Posted: Fri Jul 27, 2012 11:18 am Post subject: troubleshooting help needed

On 07/27/2012 11:10 AM, Robert L. Nuckolls, III wrote:      	  Quote: 	
		          Your original squawk:

       

                          When I'm flying         at cruise power, or even idling, the voltage wanders up and down

                 from 14.4v         to slightly less than 13v.  It does go down enough that my         Garmin

                 Aera 796         will drop off of ships power and go to it's internal battery.          This         would

                 indicate         to me that this is not a problem with the voltmeter. This does         not         seem

                 to have         any measurable cycle.  The amps stay constant at about 16 amps.

                 When I've         had the plane flying I've tried turning off equipment one at a         time         to

                 see if         that might have any effect...it didn't.

        

               So now I       think I may have some sort of a problem

               here so I       hooked everything back up and went back

               to step 4       and checked pin 4 again.  This time it

               was 1.73       volts at both pin 4 and at the alternator

               field       terminal.

       

       You didn't tell us where your ammeter was connected . . .

       in other words, what current does it measure?

       

       The fact that your bus voltage falls so low (13.0 or below)

       suggests the alternator is going off line completely and that

       the bus voltage is falling to battery delivery voltage.

       

       Your narrative also suggests that your ammeter is looking at

       ship's loads and not alternator output which would explain

       the relatively constant ammeter reading.

       

        

               So now I       think I may have some sort of a problem

               here so I       hooked everything back up and went back

               to step 4       and checked pin 4 again.  This time it

               was 1.73       volts at both pin 4 and at the alternator

               field       terminal.

       

       This is consistent with an intermittent disconnect of

       alternator field supply which. If the voltage at pin 4

       ever drops so low while pin 6 and 3 are at battery

       voltage points to failure within the regulator. Suggest

       you arrange to return it to B&C for inspection/repair.

       

                

             Bob . . .

                	
     Since the field voltage at the alt wasn't there, & came back     after the disconnect/reconnect, it might be worthwhile to disconnect     it again & do a resistance check while wiggling the wire &     terminations, prior to returning the regulator.

     

     Charlie

      [quote][b]

nuckolls.bob(at)aeroelect
Guest

Posted: Fri Jul 27, 2012 3:48 pm Post subject: troubleshooting help needed

At 11:45 AM 7/27/2012, you wrote:

  	  Quote: 	
		   Thanks Bob, 

  

 That's about what I was thinking also.  I was hoping that I would find the alternator was the problem as it's a heck of a lot easier to change.  Another question for you...I currently have the LR3C mounted on the cabin side of the firewall.  Do you see any problem with relocating it to the engine side of the firewall?  As long as I have to take it out, a real PITA, I thought I might change the location to a location that is easier to work on it in the case of another failure.  Thanks, 	


    Many of them are located on the engine side

    of the fire wall and seem to do just fine.



    We designed that critter 25 years ago and I

    never did an on-purpose thermal study. I should

    probably get one from Bill and put it in the

    chamber to see what the real ambient limits

    are. 



    Actually, temperatures on the fire wall while 

    in flight are quite benign. That's another real

    data gathering exercise that would be useful

    to conduct.



    All it takes is time and $ . . . but you're

    okay if you move it.



 

   Bob . . .    [quote][b]

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