Alternator Problem

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nrenno
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Alternator Problem

Post by nrenno »

I got a high load electrical warning shortly after taking off. The voltage remained in the middle of the green zone. Turning the master and alternator switch off and back on did not resolve the problem. However, while returning to the airport the warning disappeared.

My mechanic was able to repeat the problem on the ground, but was not able to find any problem with the alternator. He stated that the high load warning continued even after turning the engine off, indicated that the warning might be due to a sensor or G1000 issue.

Has anyone experienced a similar problem? If so, what was the cause?

My plane is a 2005 DA40.

Thanks
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nrenno
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Re: Alternator Problem

Post by nrenno »

My mechanic discusssed the alternator problem with Diamond, but did not find a solution to the problem yet. The alternator load indicator has been getting stuck in the maximum (40 Amps), while the voltage stays in the middle of the green band.

Does anyone have any insights on possible causes of this problem?

Thanks.
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Chris B
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Re: Alternator Problem

Post by Chris B »

nrenno wrote:Does anyone have any insights on possible causes of this problem?
Particularly since the problem remained with the engine off, you probably have either a significant short-circuit or defective load sensor, or intermittent connection to the load sensor. The latter two seem more likely, since a 40A short would generate a lot of heat (/flame). :shock:

One relatively simple check would be via an inductive current probe. Since the problem can (sometimes) be replicated on the ground it should be straightforward to determine if 40A is *actually* coursing through the circuits. I'd start with tapping the alternator output connection, since that is easy to access.

Chris
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nrenno
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Re: Alternator Problem

Post by nrenno »

Hi Chris,
Thank you very much for the suggestions. I will pass them to my mechanic.
Regards,
—Nilton
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nrenno
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Re: Alternator Problem

Post by nrenno »

Chris,
Thank you for the help. My mechanic at Solo Aviation found the problem. The current sensor (see picture), located behind the panel had failed. It was very difficult to find the sensor because it is hidden behind the circuit breakers.
Regards,
--Nilton
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DA40_CurrentSensor.jpg
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gordsh
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Re: Alternator Problem

Post by gordsh »

Good find, I think you should buy your mechanic a case of beer or wine. Thanks for the picture
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Lance Murray
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Re: Alternator Problem

Post by Lance Murray »

Interesting that it looks like they used a Hall effect device and not a shunt.
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Steve
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Re: Alternator Problem

Post by Steve »

Even the old VM-1000 uses a Hall effect device, one equally difficult to find behind the instrument panel...

Steve
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nrenno
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Re: Alternator Problem

Post by nrenno »

The high load electrical warning (>80 Amps) returned after he Hall effect sensor was changed, but is intermittent. The warning appears when the G1000 is turned on and disappears after a few minutes. I asked my mechanic to replace the voltage regulator to see it solves the problem.

Does anyone have other suggestions?
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nrenno
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Re: Alternator Problem

Post by nrenno »

Finally, the problem was resolved. Besides the Hall effect sensor, a diode had to be replaced. My mechanic suspects that the diode "burned out" when the sensor failed.
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