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Z14 contactor(s) circuit question

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rtitsworth

Joined: 16 Jan 2006
Posts: 76
Location: Detroit, Mi

Posted: Tue Dec 26, 2006 7:08 pm Post subject: Z14 contactor(s) circuit question

Bob, etal,



I noticed on the Z-14 schematic there is not a breaker, nor fuse, nor

fuseable link, anywhere along the current path from the battery(s) to the

battery contactor master switch(es) on the panel (and then to ground).



A short (wire failed to ground) between the contactor and the switch would

just keep the contactor closed (the same as the switch being on) and thus no

risk of additional damage, fire, etc. (due to the resistance of the

contactor coil).



However, if the contactor itself failed internally and shorted the power

terminal to the switch/coil terminal, it seems the 22AWG switch wire would

fry.



Perhaps the likelihood of that is so remote as to outweigh the complexity/

risk of an additional component in the circuit.  However, breakers and fuses

are pretty reliable and with Z14 there is Bus#2 and the cross tie, which

could be used if the #1 master breaker/fuse failed and caused the #1

contactor to open (and/or vise versa).



Thus, I am thinking of perhaps putting a fuse(s) in-line with the master

switch(es).  Thoughts?



Rick

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klehman(at)albedo.net
Guest

Posted: Wed Dec 27, 2006 5:51 am Post subject: Z14 contactor(s) circuit question

Hi Rick

FWIW I believe I added a fuse link (about two inches of 26awg wire 

inside glass sphaghetti as per the B&C kit) anywhere that I reduced 

wiring size to 22awg from a heavier than 5 amp protected circuit. As you 

say, the risk of the specific failure that you describe has to be very 

low so I think a fuse link makes more sense than a fuse. They don't 

really take up space and I would expect no corrosion or maintanance 

issues within a couple of lifetimes...

Ken



rtitsworth wrote:



 	  Quote: 	
		  



Bob, etal,



I noticed on the Z-14 schematic there is not a breaker, nor fuse, nor

fuseable link, anywhere along the current path from the battery(s) to the

battery contactor master switch(es) on the panel (and then to ground).



A short (wire failed to ground) between the contactor and the switch would

just keep the contactor closed (the same as the switch being on) and thus no

risk of additional damage, fire, etc. (due to the resistance of the

contactor coil).



However, if the contactor itself failed internally and shorted the power

terminal to the switch/coil terminal, it seems the 22AWG switch wire would

fry.



Perhaps the likelihood of that is so remote as to outweigh the complexity/

risk of an additional component in the circuit.  However, breakers and fuses

are pretty reliable and with Z14 there is Bus#2 and the cross tie, which

could be used if the #1 master breaker/fuse failed and caused the #1

contactor to open (and/or vise versa).



Thus, I am thinking of perhaps putting a fuse(s) in-line with the master

switch(es).  Thoughts?



Rick

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nuckollsr(at)cox.net
Guest

Posted: Wed Dec 27, 2006 12:10 pm Post subject: Z14 contactor(s) circuit question

At 10:06 PM 12/26/2006 -0500, you wrote:



 	  Quote: 	
		  

<rtitsworth(at)mindspring.com>



Bob, etal,



I noticed on the Z-14 schematic there is not a breaker, nor fuse, nor

fuseable link, anywhere along the current path from the battery(s) to the

battery contactor master switch(es) on the panel (and then to ground).



A short (wire failed to ground) between the contactor and the switch would

just keep the contactor closed (the same as the switch being on) and thus no

risk of additional damage, fire, etc. (due to the resistance of the

contactor coil).



However, if the contactor itself failed internally and shorted the power

terminal to the switch/coil terminal, it seems the 22AWG switch wire would

fry.



Perhaps the likelihood of that is so remote as to outweigh the complexity/

risk of an additional component in the circuit.  However, breakers and fuses

are pretty reliable and with Z14 there is Bus#2 and the cross tie, which

could be used if the #1 master breaker/fuse failed and caused the #1

contactor to open (and/or vise versa).



Thus, I am thinking of perhaps putting a fuse(s) in-line with the master

switch(es).  Thoughts?


	


   Your hypothesized failure is somewhere on the same

   order of probability as being hit by a meteor while

   on short final. The published configurations have been

   evaluated MANY times for nearly a century but have

   remained unchanged. I can see no return on investment

   for adding this feature.



   Bob . . .

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

      < What is so wonderful about scientific truth...is that >

      < the authority which determines whether there can be   >

      < debate or not does not reside in some fraternity of   >

      < scientists; nor is it divine. The authority rests     >

      < with experiment.                                      >

      <                            --Lawrence M. Krauss       >

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

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