VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 01-20-2014, 02:24 PM
Lucio I-NLCM's Avatar
Lucio I-NLCM Lucio I-NLCM is offline
 
Join Date: May 2013
Location: Milano Italy
Posts: 78
Question ANL or Automotive fuse? and...?

Hello at all

I don't wont start a "talk show" about the ANL current limiter "NON TIME DELAY" , but I'm just looking some help to better clear my doubts about this electrical system part.
I agree about put TWO limiters on the firewall for obvious reason (one from alternator before battery and the second one before feed the main buss), but I steel need some clarification.

Before question here my stuff:
-60A alternator
-about 60A (or little less) @ full load on the panel bus
-current Shunt for SV System efis

Intention:
I would routing wire in this way:
Alt B-lead >> wire x-size* to Shunt then >> copper bar to first ANL 60A (or equivalent**) then, from here, fork to >>
> the Battery via copper bar or "x-size* wire to starter relay side

AND

> via copper bar to second ANL 60A (or equivalent**) then >> wire y-size* to the panel buss bar .

Consideration :
I read here http://www.cooperindustries.com/cont...S_2024_ANL.pdf
the ANL60A is rated for blow @ about 140-150A after 20 or more seconds, logarithmically less time if current rise or a short occur, so:

Assuming the Alt became crazy or due others things the current rise over 60A , the ANL doesn't melt before reach a bunch of over two time its rated 60A.

Questions :
Is it wrong think about size the "x" and "y" wire for this big amount of current ??

* Which wire size for the "x" and "y"-size wire ?
In theory that means I'd need a cables sized well over 8 or 6 AWG to avoid melt the wire before the fuse, may be a 4 or 2 AWG will be right?.... or is it academy only?

** is there any reason why don't use most popular and cheaper automotive fuse (findable in any auto part store) like this?

http://www.mta.it/en/fuses?uniq=e717...bc78fa414a0409 look the 4th pdf from the top called "Scheda tecnica Midival" , don't worry IS IN ENGLISH, the melt curve is pretty the same as the Bussmann one (more or less seconds) why don't use those or like those ones?

Usually I prefer punch the aluminum instead think and wire electrical, so your think and suggest are pretty welcome to help me jump this big and stupid step.

Thanks in advance

Lucio
__________________
Lucio
Milano Italy
Blue-7
Reply With Quote
  #2  
Old 01-20-2014, 02:59 PM
RVDan RVDan is offline
 
Join Date: Jun 2012
Location: Frederick, MD
Posts: 821
Default

I can't think of a reason they would be a problem. The ANL fuses are sort of an industrial standard fuse here in the US so they are commonly available here.
__________________
Dan Morris
Frederick, MD
PA28-140
Hph 304CZ
RV6 built and sold
N199EC RV6A flying
Learn the facts. "Democracy dies in darkness"
Reply With Quote
  #3  
Old 01-20-2014, 03:08 PM
MarkW's Avatar
MarkW MarkW is offline
 
Join Date: Sep 2011
Location: Edgewater, FL. KSFB
Posts: 1,118
Default

Lucio,
The ANL 60 is a robust fuse. It and the fuse holder are well suited for FWF.
The smaller auto fuse may work fine. I like robust for this application.
Most only use one ANL.
#4 wire would be good for the 60a B-lead.
ANL to master solenoild is copper bar. Master to starter solenoid is copper bar. Starter and battery cable are #2.
__________________
Mark
RV9 - N14MW - Flying
G3X - ECI Titan I0-320
Catto three blade prop
http://www.mykitlog.com/MarkW

Last edited by MarkW : 01-20-2014 at 03:13 PM. Reason: added drawing
Reply With Quote
  #4  
Old 01-20-2014, 06:30 PM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,686
Default

Check the chart (43-13, 11-2), I would suggest an 8 ga wire is more than adequate for the typical RV 'B' lead.
__________________
Walt Aronow, DFW, TX (52F)

EXP Aircraft Services LLC
Specializing in RV Condition Inspections, Maintenance, Avionics Upgrades
Dynamic Prop Balancing, Pitot-Static Altmeter/Transponder Certification
FAA Certified Repair Station, AP/IA/FCC GROL, EAA Technical Counselor
Authorized Garmin G3X Dealer/Installer
RV7A built 2004, 1700+ hrs, New Titan IO-370, Bendix Mags
Website: ExpAircraft.com, Email: walt@expaircraft.com, Cell: 972-746-5154
Reply With Quote
  #5  
Old 01-21-2014, 03:57 AM
Lucio I-NLCM's Avatar
Lucio I-NLCM Lucio I-NLCM is offline
 
Join Date: May 2013
Location: Milano Italy
Posts: 78
Default

Thank for your input
but I'm confused yet, some say 8 some say 4 awg .... I think 2
How can I became sure about the right size?
So in you think the automotive fuse ( with same melt curve) should be right like the anl one , just little less robust?
__________________
Lucio
Milano Italy
Blue-7
Reply With Quote
  #6  
Old 01-21-2014, 05:48 AM
MarkW's Avatar
MarkW MarkW is offline
 
Join Date: Sep 2011
Location: Edgewater, FL. KSFB
Posts: 1,118
Default

Walt is correct that the Circular 43-13 shows that a 60 amp continuous load wire size can be #8. You will also find that your 60 amp alt. will almost never run more that 20-30 amps. This means that the 60 amps would be intermittent at best. #8 will work fine. #4 that I used is heavier and more exspensive. Also a little less voltage drop.
I still like the ANL fuse and holder.
The benifit of Experimental aircraft is that we get to build it the way we want.
__________________
Mark
RV9 - N14MW - Flying
G3X - ECI Titan I0-320
Catto three blade prop
http://www.mykitlog.com/MarkW
Reply With Quote
  #7  
Old 01-21-2014, 08:18 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
Default

Lucio,
You can download Bob Nuckolls' book free. http://www.aeroelectric.com/Book/AEC12A_PDF.zip
The majority of home-built aircraft are wired using one of Bob Nuckolls' diagrams. His circuits have been perfected and proven over time.
I agree with others that 8 AWG is adequate for the alternator. There has been some discussion on the AeroElectric list about using a MIDI fuse (which does not cost as much) instead of an ANL. http://www.matronics.com/forums/viewtopic.php
p=405736&sid=1fbb4a358d91bc8667acf5645e6f6642

and
http://forums.matronics.com/viewtopi...bb1782e2726292
The purpose of the alternator fuse is to protect the battery and wires from and a shorted alternator. The alternator will not produce much more than its rated current. It is self limiting.
Not to worry about alternator current melting wires. The alternator can not produce enough current to melt #8 wires. Only a short circuit will make that much current, which will blow the 60 amp fuse before wires get hot.
Do NOT use a fuse to feed the main bus! A fuse will add weight, cost, complexity, and is one more thing to go wrong. Factory-built planes do not fuse the main bus nor do any of Bob Nuckolls's diagrams. Instead double insulate the feeder where it passes through the firewall. The reason that a fuse is not needed in the main feeder is that a short circuit will clear itself when the sheet metal is burned away. Good workmanship and double insulating the main feeder at critical points will ensure that it never shorts out.
Joe Gores
Reply With Quote
  #8  
Old 01-21-2014, 09:26 AM
tim2542 tim2542 is offline
 
Join Date: Aug 2009
Location: Redding,Ca
Posts: 633
Default

Quote:
Originally Posted by Mich48041 View Post
The reason that a fuse is not needed in the main feeder is that a short circuit will clear itself when the sheet metal is burned away. Good workmanship and double insulating the main feeder at critical points will ensure that it never shorts out.
Joe Gores
Hi Joe
I can point to a case where the main feeder did not mend itself as described. Stainless firewall, glass airplane, burned to the ground during maintenance.
Just pointing out the importance of some very robust method of insulating this feed if it's not protected.

Tim
Reply With Quote
  #9  
Old 01-21-2014, 09:48 AM
Mich48041 Mich48041 is offline
 
Join Date: Apr 2008
Location: Riley TWP MI
Posts: 3,070
Default

Good point Tim.
Thanks, Joe
Reply With Quote
  #10  
Old 01-21-2014, 11:06 AM
jdeas's Avatar
jdeas jdeas is offline
 
Join Date: Mar 2006
Location: SoCal
Posts: 626
Default Fusable link instead of a mains fuse?

I installed a fuseable link on my mains to limit wire damage on a complete short. Same on my essential bus. Mine are short wire segments crimped or soldered (if not on a ridged mount) inline with the feed lines. No fuse or socket contact to corrode and cause problems.

The fuseable link may not save the wire but it should blow before the red hot wire burns up your whole harness!

I.E. What if your essential bus wires are in the same bundle going through the firewall as the mains when they melt?
__________________
JD
----------------------
RV-7 N314SY (KWHP)
IO-360-B1B

CANbus based trim/flaps and electrical
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 12:52 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.