Weird Alternator Problems?

[N444JN]

Can anyone help? Here is the history of my problem so far....
1. After engine start (night), the instrument panel lights started flickering. Bright, dim, bright, dim in rapid succesion. Like they were pulsating. This problem would come and go.
2. Then during the flight I notice the NAV light switch would keep turning itself off. I turn it back on then later it would be off again. Finally the switch would not hold. I stopped trying because of fear of electrical fires? This problem has stopped. Now the NAV lights stay on.
3. A week later I flew the airplane to see if the problem was still there. Nope, not this time... No panel lights flickering or NAV light switch problems. I thought!!!
4. A week later I went to fly the airplane again. On preflight I noticed the Alternator C/B was popped (35A). Yep, the battery was low (almost dead). I pushed the C/B back in, charged the battery and took it for a test flight.
5. I feel stupid, but it took me a long time to think of watching the voltmeter. I was watching the ALT C/B and was playing around with NAV lights, landing lights, strobes, etc... Also, watching to see if the panel lights would pulse or not. Then I noticed the volts were low and when I would turn on more electrical items, the volts would go down. Enough of that I said, I landed and took the alternator off.
Here is my equipment:
RV-4 wiith O-320-E3D
Mitsubishi Alternator (Rebuit no. 14194) (note: Autozone test shows good)
Transpo F7078 regulator (makes it a one-wire alternator?)
Please if anyone has any ideas!!!!
Thanks
Don

 

[Sid Lambert]

I had close to the same problem a few weeks ago.

Did you test the regulator? My alternator was acting weird, the alt tested good at the parts house and I put it back on the airplane to test again. I got the very distinct smell of electrical fire soon after I energized the field. It was a bad regulator and it fried some stuff in the alternator.

To test the system, try running the aircraft with the alt unhooked and see if you get the same voltage fluctuations. It could be something in the lighting or other electrical system.

I had the same housing alt (14597) as you but with an internal regulator.

Not that it is your resolution but I ended up going to the one Van's sells (14684) for simplicity and fan/cowl clearance.

BTW, double posting probably won't get you any help faster. Don't be surprised if they get deleted.

 

[Ironflight]

OK, so the alternator tested good you said? It still sounds as if you aren't getting new electrons into the system to me, so that would mean wiring problems, or regulator problems. Oh...was your belt tight? A loose belt could cause weak generation as well.

Lots of folks have had corroded or poor cable ends - check your crimps at the end on the alternator. If everything checks out good, I'd suspect the regulator.

The nav light switch? I am hoping that you have a circuit breaker/switch if it is physically moving to the off position....that could happen if the volts get low and the current goes up.

I'm sure smarter people than me will give you more ideas!

Paul

 

[frankh]

Pull the brushes

I've had lots of intermittent alternator issues due to the brushes wearing and dumping ground up carbon on the slip rings (the slip rings are the copper tracks the brushes run on)

Remove them and clean up all the black powdery stuff from the slip ringes with laquer thinner.

If the brushes are short (i.e worn down) replace them.

Oh to reinstall many styles of brushes are held back against their springs with a piece of safety wire until the back cover is installed..then you pull the safety wire out.

Frank