Today's Message Index:
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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
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Subject: | Re: Preferred Method for Redundant Power Sources to |
Single Input
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
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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
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Subject: | Re: FOR SALE RV6A |
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
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Subject: | Re: FOR SALE RV6A |
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