Multi-Contact parallel connectors [RE-wrenches]

[Hugh Piggott]

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At 9:25 am -0600 21/5/02, Ray Walters wrote:
>Hi Bill;
>
>The Bp2150 is a 24 vdc nom. module, so 2 modules in series make 48 vdcnom..
>Short Circuit current for the series string is 4.75 amps. I parallel 2
>strings for 9.5 amps. With the NEC 1.56 multiplier that comes to just over
>15 amps, which is the series string fuse rating of the modules and the MC
>connectors.

Ray

It seems that you are not including the back feed from the parallel 
string in the current you will see in the fault string.  Check Bill's 
origninal posting

At 12:59 pm -0700 17/5/02, Bill Brooks wrote:
>  There Ain't None
>
>Why?: Total allowable input to a series string of modules is 15 amps. Take
>the output of one string plus the string fuse and you get 9 amps (fuse) plus
>6 amps (parallel string of modules) equals 15 amps.

In your case there is a parallel string.


this has been a very interesting thread.

At 8:44 pm -0700 18/5/02, jberdner at sma-america.com wrote:
>
>If you have a fault in one sting then the current can only come from the
>other strings plus any contribution from the inverter and / or battery.

What about a fault string where all but one of the modules are wired 
in reverse?  What current can you expect in the remaining module. 
And what factors (1.56 etc) do you then apply?

Such questions will occupy great minds for a long time.

At 11:12 am -0700 20/5/02, Bob-O Schultze, Electron Connection wrote:
>In my experience, sizing an overcurrent device at Isc X 1.56 per NEC 
>on the PV side of the CC pretty much turns whatever you are using 
>into a disconnect and nothing more.


At 10:50 am -0600 21/5/02, Drake Chamberlin wrote:
>  I don't think we would ever blow a fuse unless a serious fault 
>condition occurred.

Putting these 'code freak' fuses into the module boxes and running a 
bus around the array to go to the inverter looks like solid sense to 
me.  So long as you use heavy wire on your bus.

Random thoughts from a wind generator mechanic.  :-)
-- 
Hugh

http://www.scoraigwind.co.uk/

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