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tim2542(at)sbcglobal.net Guest
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Posted: Fri Jul 09, 2010 8:10 am Post subject: Circuit protection |
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I have my electrical plan in the final draft and will post it here soon. But first I have a few questions. I will have breakers for a few items, the ignition, fuel pump, landing brake, nose lift, alternator field and pitch trim.
- I am using a Plane Power alternator with the integrated over-volt protection. I see no need for a breaker in this case, why not use a fuse?
- The nose lift (EZ type A/C) requires unswitched power to the lift and a 10A CB in the panel. This will be a long run and needs protection back at the Bat Bus also. I plan to use a fusible link for this. I also need unswitched power for the ignition (1 mag, 1 EI) and clock power. I thought I would pull the unswitched lead forward with a fusible link at the bat bus, then branch out to the nose lift, EI, and clock power. Something tells me there is a problem with this. I can’t put my finger on it other than I can hear Bob saying a bat bus is at the battery. The EI probably needs a dedicated circuit. But if the feeder was protected/sized to 15 amps, and knowing the lift only draws heavy loads when the A/C is on the ground I thought it should be ok. Thoughts?
- The rest of the breakers on the panel will be fed from the E bus and some from the Main bus, both of which are some 30”’ away. At what point (length) do I need to protect those feeder circuits using fuses or fusible links?
Thanks in advance, Tim Andres
(rnbraud(at)yahoo.com)
[quote][b]
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nuckolls.bob(at)aeroelect Guest
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Posted: Fri Jul 09, 2010 4:15 pm Post subject: Circuit protection |
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At 11:10 AM 7/9/2010, you wrote:
Quote: | I have my electrical plan in the final draft and will post it here soon. But first I have a few questions. I will have breakers for a few items, the ignition, fuel pump, landing brake, nose lift, alternator field and pitch trim.
- I am using a Plane Power alternator with the integrated over-volt protection. I see no need for a breaker in this case, why not use a fuse?
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Because it's a crowbar ov protection system that
MIGHT nuisance trip for conditions as yet undiscovered. Quote: | - The nose lift (EZ type A/C) requires unswitched power to the lift and a 10A CB in the panel. This will be a long run and needs protection back at the Bat Bus also. I plan to use a fusible link for this.
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Please don't use fusible links for any other application
than those illustrated in the Z-figures. Your gear motor
circuit would be happier with a breaker. Where is the battery
located in the airplane? Quote: | - I also need unswitched power for the ignition (1 mag, 1 EI) and clock power. I thought I would pull the unswitched lead forward with a fusible link at the bat bus, then branch out to the nose lift, EI, and clock power. Something tells me there is a problem with this. I can’t put my finger on it other than I can hear Bob saying a bat bus is at the battery. The EI probably needs a dedicated circuit. But if the feeder was protected/sized to 15 amps, and knowing the lift only draws heavy loads when the A/C is on the ground I thought it should be ok. Thoughts?
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How about a fuse for each battery bus feed system
in a fuse holder mounted right at the battery contactor? Quote: | - The rest of the breakers on the panel will be fed from the E bus and some from the Main bus, both of which are some 30”’ away. At what point (length) do I need to protect those feeder circuits using fuses or fusible links?
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Not sure what the 30" refers to. The E-bus and main
busses are separated by 30"?
Bob . . . [quote][b]
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tim2542(at)sbcglobal.net Guest
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Posted: Fri Jul 09, 2010 6:02 pm Post subject: Circuit protection |
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(rnbraud(at)yahoo.com)
From: owner-aeroelectric-list-server(at)matronics.com [mailto:owner-aeroelectric-list-server(at)matronics.com] On Behalf Of Robert L. Nuckolls, III
Sent: Friday, July 09, 2010 5:18 PM
To: aeroelectric-list(at)matronics.com
Subject: Re: AeroElectric-List: Circuit protection
At 11:10 AM 7/9/2010, you wrote:
I have my electrical plan in the final draft and will post it here soon. But first I have a few questions. I will have breakers for a few items, the ignition, fuel pump, landing brake, nose lift, alternator field and pitch trim.
- I am using a Plane Power alternator with the integrated over-volt protection. I see no need for a breaker in this case, why not use a fuse?
Because it's a crowbar ov protection system that
MIGHT nuisance trip for conditions as yet undiscovered. OK, that makes sense. - The nose lift (EZ type A/C) requires unswitched power to the lift and a 10A CB in the panel. This will be a long run and needs protection back at the Bat Bus also. I plan to use a fusible link for this.
Please don't use fusible links for any other application
than those illustrated in the Z-figures. Your gear motor
circuit would be happier with a breaker. Where is the battery
located in the airplane? On the main spar, perhaps 8’ away. - I also need unswitched power for the ignition (1 mag, 1 EI) and clock power. I thought I would pull the unswitched lead forward with a fusible link at the bat bus, then branch out to the nose lift, EI, and clock power. Something tells me there is a problem with this. I can’t put my finger on it other than I can hear Bob saying a bat bus is at the battery. The EI probably needs a dedicated circuit. But if the feeder was protected/sized to 15 amps, and knowing the lift only draws heavy loads when the A/C is on the ground I thought it should be ok. Thoughts?
How about a fuse for each battery bus feed system
in a fuse holder mounted right at the battery contactor? I can do that, I was trying to eliminate a couple of wires. - The rest of the breakers on the panel will be fed from the E bus and some from the Main bus, both of which are some 30”’ away. At what point (length) do I need to protect those feeder circuits using fuses or fusible links?
Not sure what the 30" refers to. The E-bus and main
busses are separated by 30"?
The CB’s on the panel are 30” away from the Main & Ebus, where they feed from. So I need to protect those feeds as they go to the CB’s right?
Thanks, Tim
Bob . . . Quote: | http://www.matronics.com/Navigator?AeroElectric-List | 0123456789
No virus found in this incoming message.
Checked by AVG - www.avg.com
11:36:00
[quote][b]
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nuckolls.bob(at)aeroelect Guest
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Posted: Fri Jul 09, 2010 7:36 pm Post subject: Circuit protection |
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Quote: |
The CB’s on the panel are 30” away from the Main & Ebus, where they feed from. So I need to protect those feeds as they go to the CB’s right?
Thanks, Tim
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The definition of a BUS is where the breakers and/or
fuse holders all come together. For example,
http://aeroelectric.com/Pictures/Wiring_Technique/bus_bars_1.jpg
All of those straps or "bars" between the breakers IS
one kind of bus or another. In other words, where
ever your breakers/fuses live is where the bus lives
be it the E-bus, main bus, battery bus, etc. There
are no "feeders" between a bus and the protection that
taps that bus.
Bob . . . [quote][b]
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