I had an electrical problem with the charging voltage not being what it should be on my 7A. It's fixed now (knock on wood). I thought I'd publish this to see if anyone else has had this problem or let someone know to check for this if it happens to them. Also, kudos to my A&P, Howard Yaeger at Claremore AP in Oklahoma. And kudos to B&C for their help in checking the components out.
The charging voltage had been constant since I bought the airplane about 1.5 years back. It started dropping to 12.3 volts in cruise. So I took the airplane to my A&P to trouble shoot. Howard checked everything. Static voltage here and there were all good. Alternator checked out good. Displays in the airplane were accurate. The belt was good and properly tightened. Finally, B&C asked that we send the alternator to them. They were thinking something internal in the alternator was failing, but after bench running the alternator for five hours - the alternator checked out fine. They sent it back with no charges, not even for the shipping.
One small item they mentioned was the alternator belt. Was it the right one? It had been on the airplane and doing fine since before I owned the airplane, but turns out it was not the correct belt for that alternator. The belt was in excellent shape and was tightened properly. We got the correct belt which had a much deeper V that the belt that had been on it. Amazingly, the voltage popped up to what it should be and stayed there.
So the old one was a good belt, but the wrong one for that alternator. I guess it got to a point that it started slipping even though the tension was good because the belt design did not allow it to sit as deeply in the grove of the pulley. And after 300+ hours and several years it decided to start slipping.
The charging voltage had been constant since I bought the airplane about 1.5 years back. It started dropping to 12.3 volts in cruise. So I took the airplane to my A&P to trouble shoot. Howard checked everything. Static voltage here and there were all good. Alternator checked out good. Displays in the airplane were accurate. The belt was good and properly tightened. Finally, B&C asked that we send the alternator to them. They were thinking something internal in the alternator was failing, but after bench running the alternator for five hours - the alternator checked out fine. They sent it back with no charges, not even for the shipping.
One small item they mentioned was the alternator belt. Was it the right one? It had been on the airplane and doing fine since before I owned the airplane, but turns out it was not the correct belt for that alternator. The belt was in excellent shape and was tightened properly. We got the correct belt which had a much deeper V that the belt that had been on it. Amazingly, the voltage popped up to what it should be and stayed there.
So the old one was a good belt, but the wrong one for that alternator. I guess it got to a point that it started slipping even though the tension was good because the belt design did not allow it to sit as deeply in the grove of the pulley. And after 300+ hours and several years it decided to start slipping.
