---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 08/14/13: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:31 AM - Re: AeroElectric-List Digest: 4 Msgs - 08/13/13 (Franz Fux) 2. 09:23 AM - Re: Alt field ckt breaker tripping (Robert L. Nuckolls, III) 3. 09:27 AM - Re: Alt field ckt breaker tripping (jpkarnes@comcast.net) 4. 11:56 AM - Re: Alt field ckt breaker tripping (jpkarnes@comcast.net) 5. 04:08 PM - Re: Alt field ckt breaker tripping (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 12:31:19 AM PST US From: "Franz Fux" Subject: AeroElectric-List: Re: AeroElectric-List Digest: 4 Msgs - 08/13/13 unable to respond to any mail until the 20th of August, ________________________________ Message 2 _____________________________________ Time: 09:23:23 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Alt field ckt breaker tripping At 12:40 PM 8/13/2013, you wrote: >Hi all, > > >The engine and its electrical system has flown for over 100 >hours. The battery is a brand new 12V 18AH gel battery. The plane >has not flown for over a year while some modifications/upgrades have >been undertaken. The only difference is the installation of a >secondary ignition system ala Paul Messenger's dual dizzy setup. I >really doubt that there is a short to ground that is causing this >problem. Do you recommend installing an external voltage regulator >and if so, which one? Clearing this latest hurdle is the only thing >keeping me from getting airborne again. :o) > > Okay, good data. We know this is a change from previously satisfactory operation. The battery is relatively new and not likely to be 'soggy' such that it contributes to system instability. A automotive shop has pronounced the alternator as righteous so it seems there is little probability of internal regulator failure. You can confirm by running the airplane with a voltmeter on the bus (preferably an analog meter with a needle) and see that the voltage is not only in the ballpark but not 'jumpy'. Of course, you need to disconnect the OV module. Once you have confidence in alternator performance then attention turns to the ov module. It may well be out of calibration. You can test it on the bench with an adjustable power supply. If a current limited supply, set for about 1A, if not, put an automotive tail light bulb in series with the ov module. Increase voltage very slowly until the voltage drops and/or light bulb lights. The module should trip at more than 16.0 and less than 16.5 volts. I wouldn't worry about flying without it. Using the crowbar OV module on an internally regulated alternator offers a false sense of security. There are failures internal to the regulator that cannot be externally address except with techniques like . . . http://tinyurl.com/7z6yzv9 There are dozens of suitable regulators for external control of an alternator. The problem is that you need to open your alternator, ground one field brush, bring other brush to outside world. Let's get your airplane flying first and then talk about how you're going to address over-voltage events. Bob . . . ________________________________ Message 3 _____________________________________ Time: 09:27:49 AM PST US From: jpkarnes@comcast.net Subject: Re: AeroElectric-List: Alt field ckt breaker tripping The 5A field breaker needs to have ABSOLUTE control over field excitation voltage. This generally accomplished by some modification of the alternator's internal wiring . . . like a PlanePower, or modified for external regulation like B&C. How do I achieve the state you describe above "ABSOLUTE control over field excitation voltage." This does not explain the symptoms you're seeing. I didn't fine your email address in my sales records which suggests you got the OVM from B&C. I think I purchased the OVM from you; it was probably over 10 years ago... If you like, you can send me the OVM and I'll make sure it's calibrated correctly. This is the first step toward understanding root cause for the trips. How old is your battery and what size? Battery is 12V 18AH gel battery... Thanks so much for your help!! John K. Zenith 601HDS with Stratus Subaru engine ________________________________ Message 4 _____________________________________ Time: 11:56:19 AM PST US From: jpkarnes@comcast.net Subject: Re: AeroElectric-List: Alt field ckt breaker tripping Bob, you made my day.=C2- The engine has never run better and I have adhe red to just about every recommendation you=C2-gave in your manual.=C2- I am an electrical neophyte and your input has been invaluable.=C2- I owe you a debt of gratitude!! John K. Suquamish, WA Zenith 601HDS w/Stratus Subaru/Ram heads ________________________________ Message 5 _____________________________________ Time: 04:08:12 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Alt field ckt breaker tripping At 01:55 PM 8/14/2013, you wrote: >Bob, you made my day. The engine has never run better and I have >adhered to just about every recommendation you gave in your >manual. I am an electrical neophyte and your input has been >invaluable. I owe you a debt of gratitude!! > > ' Pleased to be of service. Fly comfortably . . . 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