Generator trouble

[rupertjl]

Wanted to describe my generator problem I experienced yesterday to try to get an angle on where to start first. Took off and about 10 minutes into the flight I suddenly got some feedback in my headset and just happened to notice volt meter fluctuating/buzzing. Noticed when the static stopped in my headset, the voltmeter was stable and charging. this continued the remaining part of the 25 minute flight and I landed and shut down. Upon restart I was no longer charging even at RPM's above 1000. I shut down and tried to flash the field, but didn't get the little spark that you normally do. Restarted and still not charging. Decided to get back to the home airport and trouble shoot from there. Good thing I had new Concorde battery, it started two times with no problems to get the fuel I needed to get back home and another landing to wait out a snow squall.

I was going to start with my grounds, both to the firewall and the engine, then move to the generator and inspect the brushes, I remember George posting here on a way to check if the problem was in the generator or the voltage regulator (wouldn't rule out a ground problem) but can't seem to find it on a search.

any other wisdom form the group?

[blueldr]

Sounds to me like maybe worn brushes and commutator. How long since the generator has been overhauled?

[rupertjl]

BL, it's been before I've owned it and it's coming up on 12 years and over 350 hours. Engine was last overhauled in 89 believe...probably wouldn't hurt just to pull it and have it rebuilt just as preventative maintenance but I wanted to rule out a bad ground first before I pulled anything.

[blueldr]

In my opinion, it is time to overhaul your generator. Any competent shop will give it a run-in checkout prior to delivery.

[Roesbery]

Check your master switch. Part of it controls the field circuit to the generator. The brass contacts on these old switches get that old brass coating on them and don't make a good contact. There are some old posts somewhere on here about that.

[GAHorn]

Ground the field terminal to see if the generator will charge without a regulator. (The quick/dirty method to see if the gen is in working order or not. Do not run it this way for more than a few minutes, just to test the gen.) If it charges....the problem is elsewhere.

[cowman57]

A couple of weeks ago I left my master switch on, and had a dead battery the next time I went out to fly. After charging the battery the generator didn't charge. I then repolarized the generator and it charged again. Lesson learned....Don't use a piece of safety wire and hold it on the BAT and ARM terminals for a few seconds to make sure you have made good contact. It gets VERY hot VERY quick!

[GAHorn]

It is not necessary to "hold" the wire onto the terminals to polarize a generator.... One only needs to brush it against the terminals briefly.