Matronics Email Lists :: View topic - Alternator stops working at low idle RPM

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Alternator stops working at low idle RPM

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Dec 15, 2019 9:45 am Post subject: Alternator stops working at low idle RPM

At 06:38 AM 12/15/2019, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "racerjerry" <gnking2(at)verizon.net>



 	
 <snip>

  	  Quote: 	
		   

 If there is no field voltage, the regulator is at fault OR as previously suggested, no power is getting to the regulator.  Poor contacts on the alternator side of the master switch may be the culprit and it is not at all uncommon. 	


     Right on!



 

   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Dec 15, 2019 9:46 am Post subject: Alternator stops working at low idle RPM

At 10:37 PM 12/14/2019, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: "Argonaut36" <fmlibrino(at)msn.com>



 Today the alternator went offline again after landing, despite a raised idle and I was not able to reset it.  I turned the engine off and I re-started it after a few minutes.  The alternator did not come online. So heat seems to be causing the voltage regulator to cut off.  My regulator is a VR371S.  The S at the end means ‘sealed’ and, because it is sealed, it can be installed in the engine compartment on the firewall.  As pointed out by echristley, mine does not seem to tolerate heat well.



 

 	


      Troubleshooting an alternator system is

      a process of divide and conquer. It's either

      (1) a bad regulator or (2) alternator and just

      maybe (3) wiring.



      The first thing to do is make a temporary,

      installation of a known-good regulator as

      suggested previously. If practical, bring

      a test-wire from alternator(s) field connection

      into the cockpit and monitor voltage on that

      wire.



      If the problem repeats, what is the field

      voltage after the condition presents?

      If the problem doesn't repeat after a

      few flights, then replace the regulator . . .

      suggest you change models . . . perhaps

      make a permanent installation of your

      'test' regulator.



      If it repeats and the field voltage is

      high (greater than 6v) then the altenrator

      is bad. If the voltage is low (probably

      less than 1v) then either the regulator

      is bad or wiring is bad. It's a 99%

      probability that it's the regulator.



      Until you conduct definitive testing,

      you're at risk for spending a lot of

      time chasing herds of insignificant

      rabbits. 



 

 

   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Argonaut36

Joined: 19 May 2019
Posts: 35

Posted: Sun Dec 15, 2019 9:33 pm Post subject: Re: Alternator stops working at low idle RPM

Bob,

Many thanks for your comments and suggestions.

My airplane has a standard certificate and I cannot fly with a model of voltage regulator different from the one that I have in the airplane now.  I could do tests on the ground with another voltage regulator, but I donâ€™t see the benefit, because my alternator works normally on the ground, except after landing when the engine is hot (well above the temperatures that I see in flight).

At this point I would rule out the alternator, because I had similar problems with my previous alternator.  Two bad alternators is possible, but not very likely.  This leaves the voltage regulator and the wiring.  I checked the wires in the engine compartment (easily accessible) and replaced a section that was not in good conditions.  I also installed an additional ground line for the alternator following the instructions of the alternator manufacturer.  I did not check the wiring in the cabin, but that wiring seems to be working fine when the engine is at normal temperature and it should not see higher temperature when the engine is hot.

Any additional thoughts would be appreciated.  Thanks

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Mon Dec 16, 2019 8:14 am Post subject: Alternator stops working at low idle RPM

 	  Quote: 	
		   Two bad alternators is possible, but not very likely.  This leaves the voltage regulator and the wiring. 	


    agreed . . . and 95% probability its the regulator



 

 

   Bob . . .

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Argonaut36

Joined: 19 May 2019
Posts: 35

Posted: Mon Dec 16, 2019 10:15 am Post subject: Re: Alternator stops working at low idle RPM

Bob,



Thanks to you and all members that have provided help. I will post updates on the developments

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum