---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 11/12/09: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:09 AM - Re: Preferred Method for Redundant Power Sources to Single Input (nuckollsr) 2. 12:08 PM - FOR SALE RV6A (cecilth@juno.com) 3. 12:44 PM - Re: FOR SALE RV6A (jss165@yahoo.com) 4. 04:51 PM - Re: FOR SALE RV6A (David) ________________________________ Message 1 _____________________________________ Time: 09:09:42 AM PST US Subject: AeroElectric-List: Re: Preferred Method for Redundant Power Sources to Single Input From: "nuckollsr" When flight critical devices with a single input power connection are powered from more than one source, there are not many choices. You can use manually or automatically operated "switches" to route energy from the various sources to the electrically needy accessory . . . Manual switches are pretty obvious . . . a toggle switch transfer from NORM to ALTERNATE power source will do. Alternatively, one might install a relay that is held closed and controlled with some voltage sensing device that drops the coil and effects a transfer without pilot intervention. In the Z-Figure below . . . http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z19-RBA1.pdf http://www.aeroelectric.com/PPS/Adobe_Architecture_Pdfs/Z19-RBA2.pdf . . . I've illustrated a manually operated selection of power sources that MINIMIZES common points of failure for the two power paths that source a single load. This drawing should not be interpreted as a recommended architecture for all situations; it's only illustrative of ONE recipe for success in meeting design goals for the systems that inspired the drawing. I show a pair of diodes that are used IN THIS CASE to prevent the back-feed of power from a working to a non-working system in the even the pilot positions switches incorrectly. Obviously, a pair of diodes could be used WITHOUT switches to provide an either/or energy path from two, always-on sources. The recipe for your particular design goals may differ from that which is shown here. Power distribution diodes come in two common flavors: Silicon Junction and Schottky Junction devices. The former is used in 99% of all power steering and rectification tasks. The later has a slight advantage in that voltage drop across the conducting junction is lower and a disadvantage of being more expensive and available in fewer user-friendly package styles. The Maximum voltage drop ratings for any given device are stated for conditions of highest peak current sometimes stacked on top of the worst case for operating temperature. Its quite misleading because you're interested in average voltage drop under NORMAL conditions. Take a peek at this data sheet for a 2A, 40V rated Schottky device: http://tinyurl.com/ygbolwb Note on Figure 1 we see a plot of typical forward voltage drop characteristics. At 2A the critter nominally tosses off 0.5 volts. Now check out: http://tinyurl.com/y9y7fc7 In figure 1 of this data sheet we see a similarly rated standard junction device tosses off about .95 volts for the same conditions for a difference of about .5 volts. But for reasons I've cited many times in the past, I like the modular molded bridge rectifier blocks with fast-on tabs. They're cheap. They mount right to the airframe with no need for additional heat-sinking in most cases. Finally, they're internally insulated electrically from their mounting surfaces. Check out this data sheet: http://tinyurl.com/yzmpjbk In figure 5 we see that depending on the internal temperature of the device, we can expect voltage drops on the order of 0.6 to 0.7 at the same 2A loads. Further, the mono-block bridge with fast-on tabs offers a very robust, easy to wire, minimum risk for installation error solution for diode steering of energy around the ship's electrical system. The typical voltage drops experienced do not produce an observable degradation of performance. My preference for this class of diode has little to do with electrical performance . . . the little beasties are 25A plus rated devices and quite robust electrically for the way we use them. I judge them preferred for low cost, wide availability, mechanical convenience and minimum parts count. Bob . . . Read this topic online here: http://forums.matronics.com/viewtopic.php?p=272463#272463 ________________________________ Message 2 _____________________________________ Time: 12:08:10 PM PST US Subject: AeroElectric-List: FOR SALE RV6A From: cecilth@juno.com FOR SALE RV6A This one is for sale because I am 74 and cant get my medical renewed. This plane is complete except for upholstery. And a D-10. It has an alternative engine in it that develops over 200 hp. $27,000 with engine $22,000 without. It has a Navaid device AP-1. wing leveler. Electric Flaps Both wing tips have strobes along with the regular lights. Wings have wig wags. Apollo GX65 Flaps are electric Tiedown rings. Lift Reserve Indicator. Lets you know when you are close to a stall. Military style portable flood. Can adjust to a spot. Can adjust to red or white light. Pilot stick has military style grip. With several switches that run trim. lights, mike etc. Wing tips are finished. Vertical tips are finished. Stabilizer tips are finished. Rudder tips are finished top and bottom. The instrument panel is upgraded to a fiberglass panel with two sub panels tilted toward pilot. Wings are finished with finished tips with all lights including strobes and landing lights. More than 1,000 invested in assembly. About $15,000 invested in firewall forward which is not for sale. Call Cecil at 805 402-5308 or e-mail at (cecilth@juno.com) for questions or to arrange to see in Ventura County, Southern California. ____________________________________________________________ Free College Information Connect to the online college that best fits your needs. http://thirdpartyoffers.juno.com/TGL2141/c?cp=NhNcxlOSOJV3HMi82aVsEAAAJ1CgTD6yWnN9nTOcXhzb7nn5AAQAAAAFAAAAAA4tAj8AAAMlAAAAAAAAAAAAAAAAAAJWaQAAAAA ________________________________ Message 3 _____________________________________ Time: 12:44:30 PM PST US Subject: Re: AeroElectric-List: FOR SALE RV6A From: jss165@yahoo.com What engine is in it? ------Original Message------ From: cecilth@juno.com Sender: owner-aeroelectric-list-server@matronics.com ReplyTo: aeroelectric-list@matronics.com Subject: AeroElectric-List: FOR SALE RV6A Sent: Nov 12, 2009 2:32 PM FOR SALE RV6A This one is for sale because I am 74 and cant get my medical renewed. This plane is complete except for upholstery. And a D-10. It has an alternative engine in it that develops over 200 hp. $27,000 with engine $22,000 without. It has a Navaid device AP-1. wing leveler. Electric Flaps Both wing tips have strobes along with the regular lights. Wings have wig wags. Apollo GX65 Flaps are electric Tiedown rings. Lift Reserve Indicator. Lets you know when you are close to a stall. Military style portable flood. Can adjust to a spot. Can adjust to red or white light. Pilot stick has military style grip. With several switches that run trim. lights, mike etc. Wing tips are finished. Vertical tips are finished. Stabilizer tips are finished. Rudder tips are finished top and bottom. The instrument panel is upgraded to a fiberglass panel with two sub panels tilted toward pilot. Wings are finished with finished tips with all lights including strobes and landing lights. More than 1,000 invested in assembly. About $15,000 invested in firewall forward which is not for sale. Call Cecil at 805 402-5308 or e-mail at (cecilth@juno.com) for questions or to arrange to see in Ventura County, Southern California. ____________________________________________________________ Free College Information Connect to the online college that best fits your needs. http://thirdpartyoffers.juno.com/TGL2141/c?cp=NhNcxlOSOJV3HMi82aVsEAAAJ1CgTD6yWnN9nTOcXhzb7nn5AAQAAAAFAAAAAA4tAj8AAAMlAAAAAAAAAAAAAAAAAAJWaQAAAAA Sent from my Verizon Wireless BlackBerry ________________________________ Message 4 _____________________________________ Time: 04:51:06 PM PST US From: David Subject: Re: AeroElectric-List: FOR SALE RV6A ------------------------------------------------------------------------------------- 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.