 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
paulmillner
Joined: 09 May 2007
Posts: 21
Location: Berkeley, California
|
 Posted: Mon May 25, 2009 7:17 pm Post subject: Ground Power Receptacle - 3 pin |
 |
|
>> I assume that the military and airlines use the pin for the same thing.
In the 70's, Cessna used that small third pin, hotted up by the external
power source, to both close the ground power contactor, connecting the
external power source to the bus, *and* to energize an avionics relay,
which disconnected the avionics bus from the main bus. The relay coil
was diode or'd with the starter contactor coil circuit... so turning the
key to start *also* disconnected the avionics bus.
Where it gets exciting is when the diode from the starter contactor
fails as a short.. then, connecting ground power causes the prop to
start spinning, Youza!
Paul
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
_________________
Paul Millner, Berkeley CA [OAK] |
|
| Back to top |
|
 |
nuckolls.bob(at)aeroelect
Guest
|
| Posted: Tue May 26, 2009 2:53 pm Post subject: Ground Power Receptacle - 3 pin |
|
|
At 10:13 PM 5/25/2009, you wrote:
| Quote: |
<paulmillner(at)compuserve.com>
>> I assume that the military and airlines use the pin for the same thing.
In the 70's, Cessna used that small third pin, hotted up by the
external power source, to both close the ground power contactor,
connecting the external power source to the bus, *and* to energize
an avionics relay, which disconnected the avionics bus from the main
bus. The relay coil was diode or'd with the starter contactor coil
circuit... so turning the key to start *also* disconnected the avionics bus.
Where it gets exciting is when the diode from the starter contactor
fails as a short.. then, connecting ground power causes the prop to
start spinning, Youza!
|
Yeah . . . I remember that setup. We sure thought
it was a good idea . . . at the time . . .
Bob . . .
----------------------------------------)
( . . . a long habit of not thinking )
( a thing wrong, gives it a superficial )
( appearance of being right . . . )
( )
( -Thomas Paine 1776- )
----------------------------------------
| | - The Matronics AeroElectric-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?AeroElectric-List |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
