alpinelakespilot2000
Well Known Member
Like many others here on VAF, I'm having a bit of trouble with what appears to be nuisance trips of my Plane Power alt field. I've read through many other posts, but am hoping my specific issues will help someone tell me where I might start...
Relevant details:
1. I have the alt field protected in two places: at the fuse block and also with a 5A breaker on the panel accessible in flight. I've added the aux. fuse at my main bus fuse block in order to protect the wire between the main bus and the alt switch. (Nuckoll's shows a fusible link here, I just used a fuse.) [See wiring diagram picture or link below.]
2. It has happened 3 times in my first 10 hours of flight. Once just before my third flight. Started up, turned on my alt. field. Blew my 5A fuse, but not the 5A c/b since the latter is downstream of the fuse. Replaced that 5A fuse, no further issues.
3. Fast forward to beginning of flight #10. Started up, blew my 5A fuse when I started up and just after turning my avionics bus on. Again, did not trip the 5A c/b. Changed the fuse to a 10A (since it is only protecting a very short length of 18AWG wire), started up again and it promptly blew the 10A fuse after turning on my av bus but did not trip 5A c/b.
4. It has never happened in flight, only at startup. In flight I get good alternator output.
5. I can find no evidence of worn insulation anywhere on the alt field wire, but in places where it's buried deep in a bundle, who knows.
6. One potential culprit is a weak PC680 battery. It's the one that has suffered and been abused through the 4-5 years of building and testing. It still cranks the engine very well, but it's resting state voltage is down to 12.1V which Odyssey literature suggests means that its is down to a 40% state of charge. By the time I add strobe lights and maybe wig wag lights I'm down to about 11.7V before the alternator gets turned on. Thus, I'm wondering if the weak battery is causing the alternator to intentionally trip the field breaker. I know I should get a new battery anyway, so that is the first place I'll probably start.
7. Anyone have any other ideas?
Kind of frustrating to have the plane grounded when everything else on it works nicely! Thanks for any suggestions.
Here's a link to a diagram that might be easier to read...
http://tinypic.com/r/2jct10o/6
Relevant details:
1. I have the alt field protected in two places: at the fuse block and also with a 5A breaker on the panel accessible in flight. I've added the aux. fuse at my main bus fuse block in order to protect the wire between the main bus and the alt switch. (Nuckoll's shows a fusible link here, I just used a fuse.) [See wiring diagram picture or link below.]
2. It has happened 3 times in my first 10 hours of flight. Once just before my third flight. Started up, turned on my alt. field. Blew my 5A fuse, but not the 5A c/b since the latter is downstream of the fuse. Replaced that 5A fuse, no further issues.
3. Fast forward to beginning of flight #10. Started up, blew my 5A fuse when I started up and just after turning my avionics bus on. Again, did not trip the 5A c/b. Changed the fuse to a 10A (since it is only protecting a very short length of 18AWG wire), started up again and it promptly blew the 10A fuse after turning on my av bus but did not trip 5A c/b.
4. It has never happened in flight, only at startup. In flight I get good alternator output.
5. I can find no evidence of worn insulation anywhere on the alt field wire, but in places where it's buried deep in a bundle, who knows.
6. One potential culprit is a weak PC680 battery. It's the one that has suffered and been abused through the 4-5 years of building and testing. It still cranks the engine very well, but it's resting state voltage is down to 12.1V which Odyssey literature suggests means that its is down to a 40% state of charge. By the time I add strobe lights and maybe wig wag lights I'm down to about 11.7V before the alternator gets turned on. Thus, I'm wondering if the weak battery is causing the alternator to intentionally trip the field breaker. I know I should get a new battery anyway, so that is the first place I'll probably start.
7. Anyone have any other ideas?
Kind of frustrating to have the plane grounded when everything else on it works nicely! Thanks for any suggestions.
![2jct10o.jpg](/community/proxy.php?image=http%3A%2F%2Fi48.tinypic.com%2F2jct10o.jpg&hash=972a2d84af4b91b84ec3dc5ea6a0eb86)
Here's a link to a diagram that might be easier to read...
http://tinypic.com/r/2jct10o/6
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