Showmethemooney Posted August 16, 2013 Report Posted August 16, 2013 I have an '07 Acclaim that is exhibiting output voltages that vary 1.5 volts - from about 28.5 to nearly 30 volts while in flight. Often it appears stable but sometimes in flight, I see the voltage fluctuating the full 1.5 volt range. I am thinking the voltage should not vary more than a tenth or two tenths of a volt. I just had the brushes replaced in the alternator; we thought that might have been the problem but it did not appear to solve the fluctuating voltages. I do have noticeable alternator whine, with some pulsating that varies with engine RPM, not sure if it is related. I have a Zeftronics voltage regulator, thinking about replacing it. Any thoughts are appreciated.
Showmethemooney Posted August 17, 2013 Author Report Posted August 17, 2013 Have you checked your grounds? I am not sure I can identify all the ground points, no schematic. I did check all the master switch connections, worked them a bit by hand just in case one had a poor contact, no difference noted.
Showmethemooney Posted August 17, 2013 Author Report Posted August 17, 2013 In my case it was the Zeftronic. Thanks David. That's interesting to note. Were your symptoms the same as mine - voltage fluctuations? What year is your Ovation? Possibly a batch of voltage regulators were prone to this. My Zeftronics voltage regulator part number is A25EAM and the serial number of is T3K019. I hate to bother you to look at your log book but I would be interested to know your old regulator's serial number.
DAVIDWH Posted August 18, 2013 Report Posted August 18, 2013 Doug, Sorry, no serial #'s available as aircraft recently sold. However symptoms much the same in the air as well as taxi. They make a great regulator, but as with everything, tolerances will change over time. Hate to be just a parts changer, but if it is not regulating properly, it is a relatively cheap fix.
Showmethemooney Posted October 9, 2013 Author Report Posted October 9, 2013 I finally solved my charging system problem... thought I would share it in case someone else ever experiences the same problem. To recap, it began at first with an occasional overvoltage reading (30+ volts caused the yellow voltage alert on the G1000.) At annual, my Mooney service center adjusted the voltage regulator (actually, it is called the alternator control unit), but soon I was seeing the overvoltage again. I noticed too that the voltages were fluctuating quite a bit - about 1.5 volts. I checked impedances on the charging system circuit breakers and found the alternator voltage sense breaker to have anywhere between 3 and 90 ohms depending on when I took the measurement. I replaced that breaker and problem solved. My voltages were steady and actually fell to 26.3 volts, causing me to need to adjust the alternator control unit (voltage regulator) up about 2 volts due to the fact that we had been adjusting it down previously. I would say the ACU was seeing a varying voltage dropped by the high impedance of the breaker causing it to increase the field current to the alternator. And my headset whine was much reduced! Curious, I split the old breaker and saw that it was burned inside. - The world is right again - 1
Recommended Posts