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Starter cct. and temp rise.

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ssamps(at)GMAIL.COM
Guest

Posted: Sun Sep 16, 2007 10:06 am Post subject: Starter cct. and temp rise.

"On the other hand, an RV with the battery right behind the Firewall can tolerate 4AWG cranking circuits because the   round trip is only 4 or 5 feet long." Ref article :Wire Size Selection /  Bob Nuckolls

  

  

 I have been thinking of wiring up the starter cct on an O-320 with #4 since the run is very short, but it leads me to a couple of questions:

  

 1) Anyone know the temp rise on the wire for 250 amps for say 5 secs? (I never crank this long normally.)

 2) Anyone know what the starter current drops to, once the starter is up to speed?

  

 Thanks!

  [quote][b]

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nuckolls.bob(at)cox.net
Guest

Posted: Mon Sep 17, 2007 6:45 pm Post subject: Starter cct. and temp rise.

At 07:05 PM 9/16/2007 +0100, you wrote:



 	  Quote: 	
		  



"On the other hand, an RV with the battery right behind the Firewall can 

tolerate 4AWG cranking circuits because the

round trip is only 4 or 5 feet long." Ref article :Wire Size Selection / 

Bob Nuckolls

I have been thinking of wiring up the starter cct on an O-320 with #4 

since the run is very short, but it leads me to a couple of questions:



1) Anyone know the temp rise on the wire for 250 amps for say 5 secs? (I 

never crank this long normally.)


	


   Don't worry about it. The whole airplane's fat wires

   can be 4AWG except for LONG runs where we go to 2AWG

   to minimize wire drop.



 	  Quote: 	
		  2) Anyone know what the starter current drops to, once the starter is up 

to speed?


	


   About 200A depending on temperature and starter style.

   But 4AWG is going to be fine.



   Bob . . .



        ----------------------------------------

        ( "Problems are the price of progress. )

        ( Don't bring me anything but trouble. )

        ( Good news weakens me."               )

        (              -Charles F. Kettering-  )

        ----------------------------------------

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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:

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ssamps(at)gmail.com
Guest

Posted: Tue Sep 18, 2007 11:11 am Post subject: Starter cct. and temp rise.

Bob, thanks for the help. Steve.



 On 18/09/2007, Robert L. Nuckolls, III <nuckolls.bob(at)cox.net (nuckolls.bob(at)cox.net)> wrote: [quote]--> AeroElectric-List message posted by: "Robert L. Nuckolls, III" < nuckolls.bob(at)cox.net (nuckolls.bob(at)cox.net)>



At 07:05 PM 9/16/2007 +0100, you wrote:



 	  Quote: 	
		  



"On the other hand, an RV with the battery right behind the Firewall can

tolerate 4AWG cranking circuits because the 

round trip is only 4 or 5 feet long." Ref article :Wire Size Selection /

Bob Nuckolls

I have been thinking of wiring up the starter cct on an O-320 with #4

since the run is very short, but it leads me to a couple of questions: 



1) Anyone know the temp rise on the wire for 250 amps for say 5 secs? (I

never crank this long normally.)


	


  Don't worry about it. The whole airplane's fat wires

  can be 4AWG except for LONG runs where we go to 2AWG 

  to minimize wire drop.



 	  Quote: 	
		  2) Anyone know what the starter current drops to, once the starter is up

to speed?


	


  About 200A depending on temperature and starter style.

  But 4AWG is going to be fine. 



  Bob . . .



       ----------------------------------------

       ( "Problems are the price of progress. )

       ( Don't bring me anything but trouble. )

       ( Good news weakens me."               ) 

[b]

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