Voltage Regulator Failures

[lpaaruule]

I'm suspecting a alternator, or voltage regulator issue on my plane. My tach started reading incorrectly a few months ago. I've looked at the wiring and haven't found any issues so far.

Yesterday it seemed to fix itself. I was flying along and my voltage was at ~13.8, and RPM read the same with and without the left mag turned on (mag pickup is the secondary tach input). About 15 minutes into the flight I notice that my RPM dropped to around 1200. I knew this was incorrect, as I would have heard a difference, and felt a loss of power, which didn't happen.

At the same time I also noticed that my voltage had jumped to 14.7V.

In the past, when the tach worked, my voltage was always around 13.8. It has been in the mid to upper 14's for recently, which coincides with the incorrect tach reading.

Has anyone else had a similar issue?

[lpaaruule]

It was the regulator

[gyroron]

I am chasing a no charging issue on my plane, 3300 jabiru, and this past weekend I unplugged the regulator and ran leads from the alternator into the cockpit and ran the engine, using a voltmeter to check voltage on the alternator.

Best I could get was around 18 volts, this was with the engine at over 2500 rpms. At a fast idle it was making around 13-14 volts.

I bought two regulators off amazon to try out, and neither made any change to my charging issue. I am wondering if my alternator is just not putting out the right level of current

[pappas]

Gyroron,

For what it is worth, I also had regulator issues earlier this year. I tried to verify the alternator output with a multimeter and found a broken alternator lead which I repaired. Subsequent to that, I too bought two regulators off of amazon. Neither worked. I bought one from a local generator shop after they diagnosed my original as being bad. That one did not work either. I went through this exercise because these things should cost $15 to $20 and Sonex wants a lot more for them. I bit the bullet and ordered one from Sonex. Of course, it worked immediately. Still a little pissed... ;-)

[gyroron]

Gyroron,

For what it is worth, I also had regulator issues earlier this year. I tried to verify the alternator output with a multimeter and found a broken alternator lead which I repaired. Subsequent to that, I too bought two regulators off of amazon. Neither worked. I bought one from a local generator shop after they diagnosed my original as being bad. That one did not work either. I went through this exercise because these things should cost $15 to $20 and Sonex wants a lot more for them. I bit the bullet and ordered one from Sonex. Of course, it worked immediately. Still a little pissed... ;-)

how much was the one from sonex?

[tx_swordguy]

For a true “OEM” regulator for the jab 3300 set up look for a kubota tractor regulator. It will be about $60. I don’t have a part number off hand. I also placed a 4” 12v fan in front of mine to keep it cooler. I did not want to steal anymore cooling air from the baffles by making a blast tube. The Chinese copies if they work initially don’t seem to last long. Jeff Shultz was looking into a double throw down regulator than he was impressed with. If I remember right it was around $200 but my memory isn’t that good, at least my wife tells me that.
Mark

[peter anson]

I am chasing a no charging issue on my plane, 3300 jabiru, and this past weekend I unplugged the regulator and ran leads from the alternator into the cockpit and ran the engine, using a voltmeter to check voltage on the alternator.

Best I could get was around 18 volts, this was with the engine at over 2500 rpms. At a fast idle it was making around 13-14 volts.

I bought two regulators off amazon to try out, and neither made any change to my charging issue. I am wondering if my alternator is just not putting out the right level of current

The manual specifies 30 VAC at 3000 rpm with no load so it would appear that the stator is faulty. The fact that you have some voltage there might indicate shorts between windings.

Peter

[pappas]

[quote="gyroron"][quote="pappas"]Gyroron,

I think it was about $65

[gyroron]

I am chasing a no charging issue on my plane, 3300 jabiru, and this past weekend I unplugged the regulator and ran leads from the alternator into the cockpit and ran the engine, using a voltmeter to check voltage on the alternator.

Best I could get was around 18 volts, this was with the engine at over 2500 rpms. At a fast idle it was making around 13-14 volts.

I bought two regulators off amazon to try out, and neither made any change to my charging issue. I am wondering if my alternator is just not putting out the right level of current

The manual specifies 30 VAC at 3000 rpm with no load so it would appear that the stator is faulty. The fact that you have some voltage there might indicate shorts between windings.

Peter

Nick at jabiru USA told me that it should be making 20-30 volts at max rpm. I never got to max rpm, but at 2500-2700 rpms I was pretty close to 20 volts. He said, either it is making voltage or it isn't... That there is no need to replace the alternator if it is doing what it is currently doing. I suspect something is faulty or wired wrong in my case... I am just not sure what.

[DCASonex]

At some point a few years ago Jabiru changed from a parallel winding to series winding of the stators. The result is a bit higher voltage per RPM than earlier models. You may have the older version.

David A.