Alt load imbalance

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salim
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Alt load imbalance

Post by salim »

Hello,

During a couple of recent flights, the Right Alternator load was significantly higher than the left one.
Any idea of a possible explanation ?

Thanks a lot,

Best regards,

Salim
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Davestation
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Re: Alt load imbalance

Post by Davestation »

Unless you’re in a late model NG the regulators do not parallel and the old ones aren’t even adjustable so a small split is a function of all the subtle differences between the busses and their loads. An increasing/large split can indicate an alternator on its last leg or a regulator malfunction. One simple test would be to swap the regulators around and see if it follows.
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salim
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Re: Alt load imbalance

Post by salim »

Thank you David !

The alternators are relatively new (>180h and 6 months) as are the engines. Do you confirm the regulators are not part of the engine / alternator assembly ?

Thanks a lot

Salim
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Re: Alt load imbalance

Post by Davestation »

There is no life limit on the regulators, which are mounted in the nacelles, so if the alternators are young and healthy, those would be my next line of troubleshooting.
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Re: Alt load imbalance

Post by slowbird »

Hi Salim

Did you get this fixed? We had a the same issue for the past year on a newish DA42-VI. If you turn the right Alt Off (on the ground of course), then the left picked up the load happily. So clearly the alternator is working.

In the end we have upgraded the G1000 software and that seems to have cured the fault, for now anyway.
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Re: Alt load imbalance

Post by salim »

Hi Slowbird,

On my plane as well, any alt would pick up the load happily when opposite side was turned off.

Then the issue somehow disappeared by itself...

Now both are within 2 amps so looks fine to me

Best
Salim
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Re: Alt load imbalance

Post by wolfvoador »

Item: 9 - Airworthy
Discrepancy Hours Subtotal
C/W INSTALLATION OF WI-OSB 42NG-034 IMPROVED ALTERNATOR REGULATORS.

Corrective Action
C/W DIAMOND OSB42NG-034 INSTALLED IMPROVED ALTERNATOR REGULATORS KIT P/N
OSB-42NG-034-KIT I/A/W THIS S/B AND DA-42NG MM CH 24-31, 25-10, 71-10, 81-00 AND 76-00. OPS CHECK WITH IN LIMITS.

69.55 hours $ 7,511.40

Parts
2 EA 04001 ADHESIVE: EPOXY, RED, 3.5GM, EXTRA FAST SET (P/O: 24076)
0.5 FT 1LEZ6 SPIRAL WRAP, 3/4" NATURAL COLOR, -40 TO 122F (P/O: 11766)
2 EA CS1900KIT SEALANT (P/O: 24618) (Retail Price: 27.42)
1 EA OSB-42NG-034-KIT KIT, ALTERNATOR REGULATOR (P/O: 24518)
(Retail Price: 5,106.56)

Labor: $7,511.40 Parts: $5,220.12 Shipping: $118.20 Item Subtotal: $12,849.72

Summary of my invoice to fix the issue, almost $13,000!
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Re: Alt load imbalance

Post by slowbird »

$13k to fix a warning for an alternator that is working fine and just needed and improved regulator to make the software happy. Wow!

We had a regulator swapped for a new one, but didn’t fix the issue. Next steps was upgrade the Garmin software. Now wait and see.
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