Van's Air Force
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Alternator Whine
- Thread starter mknight
- Start date
vlittle
Well Known Member
Although a failing alternator can increase whine, it's usually a tired battery that's the problem.
An alternator puts out a high frequency pulsating DC voltage that's filtered by the battery.
If you are using ANR headsets with sensitive electronics, this problem can be exacerbated.
Filtering the alternator B lead will not help, but making sure your engine is well grounded close to the battery negative terminal and system grounds will help.
Vern
An alternator puts out a high frequency pulsating DC voltage that's filtered by the battery.
If you are using ANR headsets with sensitive electronics, this problem can be exacerbated.
Filtering the alternator B lead will not help, but making sure your engine is well grounded close to the battery negative terminal and system grounds will help.
Vern
Plane Power Alternator Noise
I have the same noise when ever the field is turned on.
It is evident when the either com radio is on.
It is especially noticeable during taxi operation.
Conyacted Plane Power they suggested going to an avionics shop.
I have not yet pressed for a solution.
I have the same noise when ever the field is turned on.
It is evident when the either com radio is on.
It is especially noticeable during taxi operation.
Conyacted Plane Power they suggested going to an avionics shop.
I have not yet pressed for a solution.
Is your alternator putting out full amperage? In a previous life as an auto mechanic I had an alternator with a failed diode that that made a whining sound similar to a bad bearing. This does not last long as the other diodes follow the first one to never never land. Hope it is just what vlittle suggested.
Bob Parry
Bob Parry
The whine is due to inductive ring-out when a stator coil still has current but the next stator in sequence has a greater voltage and so steals the conduction. Since the voltage of the previous stator is no longer high enough to conduct into the load, its remaining current oscillates with its distributed capacitance. It's somewhat analogous to the sparking at the commutator of an un-compensated DC motor. When the brushes on the commutator switch to the next bar, there is still some current flowing in the windings which then produces a high voltage through LdIdT and sparking at the brushes. So, if you're still reading this after having had to wade through this explanation, the answer is usually to put a large electrolytic capacitor across the output terminals!
