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joganand
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Join Date: Oct 2012
Posts: 16

Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/25/2012 5:22 PM

Hi friends, We have a MCCB of type NSX630F setted details as, Micrologic 5.3A,In= 630A,Io, Ir=418A,Tr=1s,(Note for other breakers Ir=__*Io) Im=3.00*Ir=1254A,Tm=0.30s I2t=OFF, Iinst=11.00*In=6930. Excluding above,please add points of setting and their meaning of other terms used in Main breakers Best regards, Joganand
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lyn
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#1

Re: Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/25/2012 5:57 PM

Glossary of Circuit Breaker Terms
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TonyS
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#2

Re: Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/25/2012 7:39 PM

You could try RTFM

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lyn
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#3
In reply to #2

Re: Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/25/2012 7:46 PM

Or, RTFTB. TB= text book.
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Joshi
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Join Date: Oct 2007
Location: India
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#4

Re: Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/25/2012 11:58 PM

In the links, look in MCCB NSX630F test data sheet

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cuba_pete
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#5
In reply to #4

Re: Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/26/2012 10:58 AM

Can you believe that the U.S. gov't blocks google.co.in?

Weird..."Access to this site has been denied to safeguard the security posture of the NMCI network. If there is an operational requirement to access this website or link, contact the NAVNETWARCOM NETOPS2."
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Joshi
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#6
In reply to #5

Re: Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/26/2012 11:31 AM

Find it strange. There is nothing remotely objectionable in the link. Some goof-up, I suppose.
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nelson1
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Join Date: Dec 2007
Location: Dubai
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#7

Re: Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/27/2012 1:15 PM

Please refer to the manufacturer to understand fully the functions and settings - On ABB breakers manuals are accessible and easily understood.

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RG2
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Location: Kansas
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#8

Re: Meaning of Terms (In,Io,Ir,Im,tr,Iinst) on the Breaker

10/28/2012 1:03 PM

The In is Current (I) in (n), Io is Current (I) out (o), Ir is Current rating, Im is current (I) multiplier (m) and Iinst is Instantaneous (inst) current (I).

The device uses a Micrologic unit which is set to have an input current coming into the Micrologic unit of 5.3 amps which corresponds with an actual current of 630A through the breaker. The 5.3A comes from a CT (current transformer) to allow the Micrologic unit to function. The CT will also give an input of differing levels based on actual current through the breaker.

The breaker is set to a current rating (Ir) of 418A with a time rating (tr) of 1 second. This means that the breaker will trip in 1 second once it reaches 418A.

Im=3.00*Ir=1254A, Tm=0.30s (seconds) I2t This says with a current multiplier of 3.00 and a Current rating of 1254A that the breaker should trip in 3/10ths of a second once the current through the breaker reaches 1254A. I2t=OFF (Instantaneous trip is not on for this setting.)

Iinst=11.00*In=6930A This means that if the current through the breaker reaches 6930A the breaker will trip instananeously.

Your Micrologic unit has a "curve" designed into it which will cause the breaker to trip instantaneously at your programmed setting of 6930A and will trip at 1254A after 0.3 seconds. It will also trip at 418A after a one second delay. This curve can be charted on a graph of Current vs. Time.

You should have a Micrologic manual by Schneider Electric that came with your unit. If you do not, you should request one.

www.schneiderelectric.es/html/compactnsx/...nsx/.../page_218.pdf
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cuba_pete (1); Joshi (2); lyn (2); nelson1 (1); RG2 (1); TonyS (1)

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