Lan Vinh Do

Lan Vinh Do

Well Known Member
Hi
I made a flight over the water today. Half way me and my passenger notice what we tought was a alarm in the headset. . It was a high frequency that was beeping at a speed around twice per second. I look at my ELT, Co2 detector, my eis and everything was fine. Turn strobe and nav light off ... no change. It's really a new noise and it's not continous ( i have 250 hre myself on the aircraft)

Then i turn off my alternator and the sound stop but came back as soon as i turn it on. It was still charging, amp was showing 23 , voltage 14.6
The plane have 350hre. It's the stock alternator that was coming with the FWF of the rv-10 in 2005.
on the approach and landing, the frequency and the tone of the noise went down with the rpm but it's still there at idle.
could notice a hum in my headset for the first 2min after engine start but it was stoping by itself after. Not sure it'S the same kind of noise.


i think i will take the alternator off and have it rebuilt. Any Idea before i do this?

Thank You
 
Check ALL electrical connections to make sure they are clean and tight, not just the alternator but also the audio system. Especially check grounds.
Joe Gores
 
Noise regular but not continuous

I will do that. I was curious about the fact that it's not a continuous sound. In my older plane I could hear the strobe. But this is really regular and vary exactly with the rpm. Really sound like an alarm. Not sure a bad ground would do this but I will check everything.
 
Alt noise

Try to get it bench checked. You may have a diode breaking down.



Don Broussard
RV 9 Rebuild in Progress
 
Don't forget to check simple stuff - what changed? Did your passenger plug in their headset? Could they have accidentally disturbed the jacks such that the isolating washer shifted and the jack is creating a ground loop? If I get a new symptom, I check what just happened that might cause it.

Paul
 
had the same situation a couple years ago. added a cheap gadget to the alternator and been fine since then. :)

3mc6.jpg
 
Is it about to fail

I will remove it and have it bench test. I am more concern if it's a sign that the alternator will fail soon. I am flying IFR. I have my back-up but still want to be confident in the plane. The noise..I would like to find the source but can live with it.
My headset jack are on the overhead console ( fiberglass) so not worry for isolation.

Thank you for all the advice. Any new idea are welcome.

PS. When I was at the ILes de la Madeleine airport yesterday, there was 4 RV, one lancair and one money. 5 homebuilt for one certified. I love this.
 
rectifier

Had the alternator bench test this morning.
A short in the rectifier.

When i took a look to my engine data on savvy, my voltage was always 14.4 to 14.5 but the last flight it was 14.7 to 14.8v.

It will be ready with a new rectifier this afternoon and 50$. ready to fly tonight.
My hangar neighbour is jealous. It would have grounded his piper for 2 week and probably 500 or more$.
 
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