 |
Matronics Email Lists
Web Forum Interface to the Matronics Email Lists
|
| View previous topic :: View next topic |
| Author |
Message |
Erich_Weaver(at)URSCorp.c
Guest
|
 Posted: Wed Jan 11, 2006 9:59 am Post subject: Z-13 questions |
 |
|
Greetings
Im beginning to get up to speed in preparation for installation of my
RV-7's electrical system, but have some remaining questions. Regarding
Bob's Z-13 architecture:
(1) I see no protection built in for the wire between the battery contactor
and the main bus. Why would this be? In my case,, this wire will need to
run from the front of the firewall to somewhere on my subpanel, so the wire
length isnt entirely trivial.
(2) Im confused about the wire between the connection terminal for the
main bus and the DC power master switch. Why have a wire with a fusible
link coming off the bus connection terminal when you could just have the
wire hooked up to the bus with a standard fuse like the other circuits? I
know Im missing something...
Thanks. How did people wire planes before the list?
Erich Weaver
| | - 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 |
|
 |
nuckollsr(at)cox.net
Guest
|
| Posted: Thu Jan 12, 2006 6:48 am Post subject: Z-13 questions |
|
|
At 09:58 AM 1/11/2006 -0800, you wrote:
| Quote: |
Greetings
Im beginning to get up to speed in preparation for installation of my
RV-7's electrical system, but have some remaining questions. Regarding
Bob's Z-13 architecture:
(1) I see no protection built in for the wire between the battery contactor
and the main bus. Why would this be? In my case,, this wire will need to
run from the front of the firewall to somewhere on my subpanel, so the wire
length isnt entirely trivial.
|
The "fat" wires in light aircraft are not generally "protected" by
more that considered installation to prevent hazardous faults both
along the length of the wire and at the load distribution end (bus).
This philosophy has been in place since day one and has and experience
base of over 250,000 aircraft. There's been no incidents that have
prompted a revision to the philosophy.
| Quote: | (2) Im confused about the wire between the connection terminal for the
main bus and the DC power master switch. Why have a wire with a fusible
link coming off the bus connection terminal when you could just have the
wire hooked up to the bus with a standard fuse like the other circuits? I
know Im missing something...
|
I you choose to use a fuse block in conjunction with an alternator
control having a crowbar ov protection system, you'll want a circuit
breaker on the panel which is an EXTENSION of the bus from the fuse
block to the breaker. The time constant of fuses is MUCH too fast to
run upstream of a breaker during the crowbar event . . . hence
the fusible link.
Bob . . .
| Quote: | Thanks. How did people wire planes before the list?
|
See chapter 17 and in particular Figure 17-1 of the 'Connection.
Alternatively, a cursory inspection of the service manual for
any certified light aircraft will show what's been in place
for about the last 90 years. Not a BAD way to do it. 250,000
happy airplane owners can't be wrong. If you wanted to wire
your airplane exactly the same way (recommended by many of the
kit manufacturers) it would perform as advertised.
Options in the 'Connection and discussed here on the list are
offered for consideration of those who would like to have
more control over their project's electrical system. These options
are in no way intended to be recommendations against anyone choosing
to go with the traditional architectures and hardware.
Bob . . .
| | - 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 |
|
|
hdwysong(at)gmail.com
Guest
|
| Posted: Thu Jan 12, 2006 9:45 am Post subject: Z-13 questions |
|
|
A followup of question (2) from the peanut gallery, Bob...
Could you oversize the fuse in the fuseblock that feeds the 5A OVP CB to
"guarantee" the breaker pops before the fuse blows? Is there a fuse rating
that'll provide the same level of hard fault protection as the 22 AWG
fuselink while still allowing the 5A OVP CB to pop first?
D
----------
On 1/12/06, Robert L. Nuckolls, III <nuckollsr(at)cox.net> wrote:
| Quote: |
nuckollsr(at)cox.net>
At 09:58 AM 1/11/2006 -0800, you wrote:
>
>
>Greetings
>
>Im beginning to get up to speed in preparation for installation of my
>RV-7's electrical system, but have some remaining questions. Regarding
>Bob's Z-13 architecture:
>
>(1) I see no protection built in for the wire between the battery
contactor
>and the main bus. Why would this be? In my case,, this wire will need
to
>run from the front of the firewall to somewhere on my subpanel, so the
wire
>length isnt entirely trivial.
The "fat" wires in light aircraft are not generally "protected" by
more that considered installation to prevent hazardous faults both
along the length of the wire and at the load distribution end (bus).
This philosophy has been in place since day one and has and experience
base of over 250,000 aircraft. There's been no incidents that have
prompted a revision to the philosophy.
>(2) Im confused about the wire between the connection terminal for the
>main bus and the DC power master switch. Why have a wire with a fusible
>link coming off the bus connection terminal when you could just have the
>wire hooked up to the bus with a standard fuse like the other
circuits? I
>know Im missing something...
I you choose to use a fuse block in conjunction with an alternator
control having a crowbar ov protection system, you'll want a circuit
breaker on the panel which is an EXTENSION of the bus from the fuse
block to the breaker. The time constant of fuses is MUCH too fast to
run upstream of a breaker during the crowbar event . . . hence
the fusible link.
Bob . . .
>Thanks. How did people wire planes before the list?
See chapter 17 and in particular Figure 17-1 of the 'Connection.
Alternatively, a cursory inspection of the service manual for
any certified light aircraft will show what's been in place
for about the last 90 years. Not a BAD way to do it. 250,000
happy airplane owners can't be wrong. If you wanted to wire
your airplane exactly the same way (recommended by many of the
kit manufacturers) it would perform as advertised.
Options in the 'Connection and discussed here on the list are
offered for consideration of those who would like to have
more control over their project's electrical system. These options
are in no way intended to be recommendations against anyone choosing
to go with the traditional architectures and hardware.
Bob . . .
|
| | - 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 |
|
|
nuckollsr(at)cox.net
Guest
|
| Posted: Sat Jan 14, 2006 9:06 am Post subject: Z-13 questions |
|
|
At 11:41 AM 1/12/2006 -0600, you wrote:
| Quote: |
A followup of question (2) from the peanut gallery, Bob...
Could you oversize the fuse in the fuseblock that feeds the 5A OVP CB to
"guarantee" the breaker pops before the fuse blows? Is there a fuse rating
that'll provide the same level of hard fault protection as the 22 AWG
fuselink while still allowing the 5A OVP CB to pop first?
|
Sure. I did some experiments with the ATC fuses a few years ago.
25A fuses will stay in place upstream of a 5A breaker. 30A
wouldn't hurt anything. You might want to upsize the feeder from
fuse to breaker to maybe 18AWG. But the fusible link makes
so much sense here, I wouldn't recommend it.
Bob . . .
| | - 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 |
|
|
klehman(at)albedo.net
Guest
|
| Posted: Sat Jan 14, 2006 10:49 am Post subject: Z-13 questions |
|
|
FWIW if the alternator is internally regulated and the b lead goes
through a contactor, then the CB can be downsized as it only has to
power the contactor coil instead of supply the field current. I happened
to have a 2 1/2 amp (2.5 amp) CB on hand and it works just fine when fed
off the fuse block through a 10 amp fuse. After many crowbar OVP test
trips, the fuse has never failed. Being picky, I used 18awg wire
downstream of the fuse to insure that the wire doesn't overheat if
shorted, and I'd go to larger wire in accordance with normal practice if
using a larger fuse and a 5 amp breaker. While I used a few fuse links
in other places, it was just very convenient and simple to feed the OV
breaker off a fuse in my bird. A fuse link quickly starts to make more
sense if one is comparing a fuse link and 22 awg wire to a 25 or 30 amp
fuse and substantially heavier wire.
Ken
Robert L. Nuckolls, III wrote:
| Quote: |
At 11:41 AM 1/12/2006 -0600, you wrote:
>
>
>A followup of question (2) from the peanut gallery, Bob...
>
>Could you oversize the fuse in the fuseblock that feeds the 5A OVP CB to
>"guarantee" the breaker pops before the fuse blows? Is there a fuse rating
>that'll provide the same level of hard fault protection as the 22 AWG
>fuselink while still allowing the 5A OVP CB to pop first?
>
>
Sure. I did some experiments with the ATC fuses a few years ago.
25A fuses will stay in place upstream of a 5A breaker. 30A
wouldn't hurt anything. You might want to upsize the feeder from
fuse to breaker to maybe 18AWG. But the fusible link makes
so much sense here, I wouldn't recommend it.
Bob . . .
|
| | - 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
