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B&C 60Amp alternator failure modes

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recapen(at)earthlink.net
Guest

Posted: Thu May 01, 2025 9:58 am Post subject: B&C 60Amp alternator failure modes

During a stabilized cruise, I noticed my voltage drop to 12.8.  

The backup alternator did not come on line (no indicator light).  

After a few minutes, voltage was back up to 13.3.

I usually see 13.5 as it is behind an E-Buss diode.

 

Am I looking at a slowly dying alternator?  15 years old – about 450 hours.

 

Thoughts?

 

Thanks,

Ralph Capen

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user9253

Joined: 28 Mar 2008
Posts: 1938
Location: Riley TWP Michigan

Posted: Thu May 01, 2025 6:25 pm Post subject: Re: B&C 60Amp alternator failure modes

The vast majority of electrical problems are due to bad connections, 

for instance loose or corroded terminals.

Another possibility is an indication problem with the voltmeter.

Connect a separate voltmeter to the main bus to verify that the voltage is actually dropping.

Other possibilities are worn alternator brushes or a loose belt.

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_________________
Joe Gores

recapen(at)earthlink.net
Guest

Posted: Fri May 02, 2025 3:46 am Post subject: B&C 60Amp alternator failure modes

Thanks Joe,



I have a spot where I can check the voltage directly at the battery - I will

set that up for the next test flight!

The belt is the next easiest to check...

I can reseat all of the connections...



Anyone know how to check for worn brushes?



Thanks again,

Ralph



--

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chaskuss(at)yahoo.com
Guest

Posted: Fri May 02, 2025 11:51 am Post subject: B&C 60Amp alternator failure modes

The B&C alternators are based on real Nippon Denso alternators. Depending on the model and the age of the alternator, you may be able to remove the brush pack externally. The older model alternators brush pack is retained with 2 screws at the rear of the alternator. Take the screws out and you can withdraw the brush pack. 

 Once the brushes wear to the point that less than 1/2 of the remaining brush is held inside the brush holder, they can "cock" and bind up. Same thing that can happen on your car, truck, motorcycle or aircraft's brake calipers. Once more than 50% of the piston comes out of the caliper, it will "cock" and bind up. This is the reason that there is a minimum thickness for both brake rotors and brake pads.... to prevent that from happening. 



 Ralph, send me a photo of the rear of your B&C. I can then highlight where the mounting screws are, assuming it's the correct style of alternator.



Other alternator style require you to split the 2 case haves of the alternator to inspect the brushes.  Once the alternator is removed, that is a fairly easy job. 



Charlie Kuss [rhymes with puss]



PS I've CC'd this email to you personally, in case you don't have my email address.



            

                                                                                            On Friday, May 2, 2025 at 07:57:22 AM EDT,  <recapen(at)earthlink.net> wrote:                    

                    



                    



                                                --> AeroElectric-List message posted by: <recapen(at)earthlink.net (recapen(at)earthlink.net)>



Thanks Joe,



I have a spot where I can check the voltage directly at the battery - I will



set that up for the next test flight!



The belt is the next easiest to check...



I can reseat all of the connections...



Anyone know how to check for worn brushes?



Thanks again,



Ralph



--

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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:

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