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  #1  
Old 11-19-2012, 12:44 PM
humptybump humptybump is offline
 
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Default Requesting Review: modern electrical diagram

I am designing a panel and have a sense for what I want the end result to be.
With that said, there are a few "I think" areas of my design and anytime I say "I think" it really means, "get help"!

Below is my high level plan for power. There are [at least] three questions I would like assistance with (each question has a matching label on the diagram):


Q#1 - Is the Battery + Alternator circuit really this basic ?

Q#2 - Should the button switches on the stick (being used for the flaps) be protected by their own breaker ?

Q#3 - Do the two electrical buses need their own 'main' breakers and if so, how are they sized ?


Also, if you see real errors and places that are not safe, please point those out as well.

I very much appreciate the help !


click for larger image

Updated Diagram to 1.1:

click for larger image

Last edited by humptybump : 11-20-2012 at 09:58 AM.
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  #2  
Old 11-19-2012, 01:04 PM
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RV6_flyer RV6_flyer is offline
 
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Where is the Voltage Regulator for the Alternator? You also should have circuit protection between the alternator and battery.

A1. Yes after you add a voltage regulator and OVP to the alternator.
A2. Each circuit (not switch) requires its own circuit protection. (Fuse or CB)
Tie the switch into the same CB.
A3. IF all the wire from the 60 Amp fuse is sized for 60 amps all the way to the next fuse or circuit breaker, then no. IF you go to a smaller gauge wire anywhere after the 60 Amp Fuse before you go to another circuit protector, then you need circuit protection sized for the smaller gauge wire.
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Last edited by RV6_flyer : 11-19-2012 at 01:07 PM.
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  #3  
Old 11-19-2012, 01:21 PM
humptybump humptybump is offline
 
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Quote:
Originally Posted by RV6_flyer View Post
Where is the Voltage Regulator?
Do modern alternators have the voltage regulator buit-in / integrated ?
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  #4  
Old 11-19-2012, 01:31 PM
BobTurner BobTurner is offline
 
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I assume you are using a PP alternator with internal regulator.
You don't show the stater wiring. It cannot go thru that 60 amp CB.
Many people protect the alternator with a 60 A CB but protect the battery separately, with a very heavy duty fuse, and run it directly to the bus(es), so if the 60A CB fails at least you have battery power available. Or some don't protect the battery wiring at all except to hope the master relay drops in and out without welding the contacts in case of a direct short.
I would move the 5A flaps CB to protect the up/down switch wiring, too.
You don't show the wiring labeled "landing plus taxi" and "taxi" but taken at face value you will need diodes for isolation to achieve the desired result (e.g., if these wires are connected as labeled then turning on taxi, the power will run backwards thru the wires and turn on the landing light too).
I'm not sure why you have two buses but only one power source, except that if one of those switches fail, you still have half the avionics?
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  #5  
Old 11-19-2012, 01:41 PM
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RV6_flyer RV6_flyer is offline
 
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Quote:
Originally Posted by humptybump View Post
Do modern alternators have the voltage regulator buit-in / integrated ?
Best aircraft practice is to have a separate voltage regulator and Over Voltage Protection.

Internal voltage regulator is fine on a car or ground vehicle but not on MY airplane.
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  #6  
Old 11-19-2012, 01:57 PM
humptybump humptybump is offline
 
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Great questions and comments. Here is some of what I was thinking.

Quote:
Originally Posted by BobTurner View Post
I assume you are using a PP alternator with internal regulator.
Yes.

Quote:
Originally Posted by BobTurner View Post
I would move the 5A flaps CB to protect the up/down switch wiring, too.
The grip is a Ray Allen and the documentation says they are only good for 1A. If they were 5A I could do without the relay. So I'm guess I should have a 1A CB between the buss and tho grip switches ?

Quote:
Originally Posted by BobTurner View Post
You don't show the wiring labeled "landing plus taxi" and "taxi" but taken at face value you will need diodes for isolation to achieve the desired result.
The switch is a DPDT ON-ON-ON. I stole the wiring from the B and C website. Their drawing of the switch is much better than my symbol and it will do what I suggested. But, you're point is well taken and I will test it on the bench for sanity.

Quote:
Originally Posted by BobTurner View Post
not sure why you have two buses
My theory is the two buses will allow me to quickly dump all non essential usage with a single switch. Down the road, I am likely to add a second battery with diode isolation. But that is just complicating my current learning curve too much.
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  #7  
Old 11-19-2012, 02:16 PM
humptybump humptybump is offline
 
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Thanks Gary, I think I see a new problem in my plan ...

Quote:
Originally Posted by RV6_flyer View Post
if you go to a smaller gauge wire anywhere after the 60 Amp Fuse before you go to another circuit protector, then you need circuit protection sized for the smaller gauge wire.
The switches I planned to use (700-1-2 ON-OFF) are from B and C. Based on a paper by Bob Nuckolls (posted on the B and C website), these switches are conservatively rated at 15A and some at 20A.

Update: reviews of others' implementations suggests the Bus switches need to be relays to handle the current, unless there is a 60A switch out there that does not look (or cost) huge.

Last edited by humptybump : 11-19-2012 at 02:54 PM.
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  #8  
Old 11-19-2012, 02:16 PM
krw5927 krw5927 is offline
 
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The Aeroelectric diagrams show the alternator output (B terminal) on the same side of the master contactor as the battery. Is there a reason you put it on the opposite side here?

Better question: Is there a reason NOT to do it as depicted by Humpty (assuming the 5A field breaker is pullable)?
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  #9  
Old 11-19-2012, 02:26 PM
humptybump humptybump is offline
 
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Quote:
Originally Posted by krw5927 View Post
The Aeroelectric diagrams show the alternator output (B terminal) on the same side of the master contactor as the battery. Is there a reason you put it on the opposite side here?
I hope someone will answer your second question as I have not seen the Aeroelectronics diagram your mentioned.

I stole the battery+alternator portion of my diagram from Bob Ellis. (G-JBTR) and Paul Dye.


The 5A CB is pullable.

Last edited by humptybump : 11-19-2012 at 02:49 PM.
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  #10  
Old 11-19-2012, 02:41 PM
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Brantel Brantel is offline
 
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Quote:
Originally Posted by krw5927 View Post
The Aeroelectric diagrams show the alternator output (B terminal) on the same side of the master contactor as the battery.

Which one? Are you sure?
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