Charging problem

[Walter Henson]

I have a '73 F33A and after going to my last maintenance inspection I decided to send my alternator in to be checked out. It ended up being a full rebuild. After it was reinstalled it worked fine the first trip around the pattern until landing when it shut down, then restarted once I idled down. I then flew 60 miles to another airport and it shut down again shortly after takeoff.
I could turn off the alt switch for a few minutes, and then turn it back on and it would charge for about 5 to 10 seconds. It would hold voltage at 13.9V and amperage would spike up to about 25 amps, then reduce down to about 15 amps at an expected rate, then drop off to negative. When I landed it charged fine while I was idling at 8 amps, but kicked back off when I got in the air, (maybe during takeoff). The A & P marked the wires and is pretty confident he installed them correctly. The voltage never spikes, I have an MVP-50 and the voltage reads 13.9 when the alternator is charging. I didn't have any charging problems before the rebuild.
Any ideas?

[Thomas Pelz]

Walter,

I had something similar happen to me.  I am not certain what happened. 

I would find that my alternator would drop off line at the most inconvient time.

Finally, I replaced the voltage regulator.  That solved the whole problem.

I suspect that something on a prior alternator messed up.  I had to replace the alterntor.  This then messed up the voltage regulator.

For the past 1 year I have not a had a problem.

Need a 24 V Alternator?  I have an extra one.  I put a 550 in my Bonanza out of a 24 V Bonanza.  Part number is presolite 9522.

Tom

[Andrew Hesketh]

Could be Voltage Regulator but check the cheap item first. Verify that you have good continuity (or voltage) from your alternator field switch to the alternator.  There is probably an in-line fuse, make sure it is making good contact inside the fuse holder.  Make sure this field wire is not intermittently going to ground (since this occurs in flight, in-flight vibrations causing make-break contact).  How do I know?  Just had this happen on my plane, bad fuse holder contact.

Andy

[Thomas Pelz]

My voltage regulator was only about $150 .   It is a Zeftronics device.

The alternator was a lot more.


Tom

[Walter Henson]

It was something in the alternator. I sent it back to the shop that overhauled it and they confirmed it. They couldn't figure out what it was, so they sent me a Hartzell reman at no cost. It's worked great ever since, but I was down six months before we figured it out.