---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 09/28/23: 2 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:15 AM - Re: Potential for Overvoltage Issue (Robert L. Nuckolls, III) 2. 10:31 AM - Re: OVM14 MkIII, rev P1 (user9253) ________________________________ Message 1 _____________________________________ Time: 10:15:24 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Potential for Overvoltage Issue At 10:01 AM 9/27/2023, you wrote: >Hi Bob, > >Thanks for your response. But, remember in this case we are dealing >with a user modified alternator, not factory. . . .and your skill set is not equal to or greater than 'factory'? >The two failure events you list are linked in a chain so their >probabilities can't be considered independently. You can consider them in any manner that you wish. >In this case, if the screw with it's insulating sleeve were to back >out exposing >it's threads the ring terminal or brush lug would only have to move 0.020" >to make contact and cause a uncontrolled overvoltage event. The probability >of that much movement in a high vibration environment is almost guaranteed. We've discussed the value of high pressure, gas tight connections to insure conductor integrity . . . how likely is it that this terminal, having succumbed to a 'high vibration' environment and now flailing around in the breeze is going to experience the necessary force/area PLUS dwell time to form a conduction pathway necessary to produce the condition of concern? >I do agree that making that event extremely improbable so that it >doesn't need to be >considered is the best approach. I believe I had put Loctite on that screw. Locking fasteners are good too . . . >I think the next time I'm in there I will put a blob of JB-Weld over the screw >and terminal, potting the area, as a belt and suspenders to make >sure that it never moves. Seems you have answered your own question. If you have concerns and perceive a mitigating action, then by all means. My offering to this thread suggests that quality of workmanship and robust design are the first lines of defence for failures . . . OV management systems are a 'band aid' that addresses conditions for which we have no influence on design/craftsmanship. Bob . . . //// (o o) ===========o00o=(_)=o00o======== < Go ahead, make my day . . . > < show me where I'm wrong. > ================================ In the interest of creative evolution of the-best-we-know-how-to-do based on physics and good practice. ________________________________ Message 2 _____________________________________ Time: 10:31:47 AM PST US Subject: AeroElectric-List: Re: OVM14 MkIII, rev P1 From: "user9253" A wise man once said, "That popped circuit breaker just prevented a fire. Do you want to reset it and give the fire a second chance?" Adding a 50 cent TO-92 part and a LED could save much time troubleshooting the cause of the tripped breaker. More importantly, if the LED is illuminated, the pilot will know that it is safe to reset the breaker. If the LED is off, then it is best to wait until safely on the ground before resetting the breaker. The suggested LED has a narrow beam angle and should be aimed toward the pilot's face. I modified Bob N's circuit below by adding an SCR and external LED circuit. And thanks Eric for your help. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=511525#511525 Attachments: http://forums.matronics.com//files/ov_indicator_158.png ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.