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    Operating and Installation Conditions

    Uploaded by

    James George
    This document provides guidance on setting or calculating the tripping time for thermal magnetic circuit breakers under different operating temperatures. It includes: 1) A correction factor table to adjust the rated current based on the operating temperature, to determine the proper setting or tripping time. 2) An example calculation showing how to determine the correct setting to obtain a real rated current of 105A at different temperatures. 3) An example calculation of the tripping time at rated current for an overload of 500A at different temperatures. 4) A note that additional correction factors are needed for rated currents between 0.7-0.9 times the rated current.

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    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd

    Operating and Installation Conditions

    Uploaded by

    James George
    16 views1 page
    This document provides guidance on setting or calculating the tripping time for thermal magnetic circuit breakers under different operating temperatures. It includes: 1) A correction factor table to adjust the rated current based on the operating temperature, to determine the proper setting or tripping time. 2) An example calculation showing how to determine the correct setting to obtain a real rated current of 105A at different temperatures. 3) An example calculation of the tripping time at rated current for an overload of 500A at different temperatures. 4) A note that additional correction factors are needed for rated currents between 0.7-0.9 times the rated current.

    Original Description:

    CB trip time calculations

    Original Title

    Fa 312598

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    © © All Rights Reserved

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    This document provides guidance on setting or calculating the tripping time for thermal magnetic circuit breakers under different operating temperatures. It includes: 1) A correction factor table to adjust the rated current based on the operating temperature, to determine the proper setting or tripping time. 2) An example calculation showing how to determine the correct setting to obtain a real rated current of 105A at different temperatures. 3) An example calculation of the tripping time at rated current for an overload of 500A at different temperatures. 4) A note that additional correction factors are needed for rated currents between 0.7-0.9 times the rated current.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    16 views1 page

    Operating and Installation Conditions

    Uploaded by

    James George
    This document provides guidance on setting or calculating the tripping time for thermal magnetic circuit breakers under different operating temperatures. It includes: 1) A correction factor table to adjust the rated current based on the operating temperature, to determine the proper setting or tripping time. 2) An example calculation showing how to determine the correct setting to obtain a real rated current of 105A at different temperatures. 3) An example calculation of the tripping time at rated current for an overload of 500A at different temperatures. 4) A note that additional correction factors are needed for rated currents between 0.7-0.9 times the rated current.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 1

    www.schneider-electric.

    com
    Installation recommendations
    Operating and installation conditions

    Doing the setting or calculating the tripping time for a given 10 000
    5 000
    temperature: 2 000
    $IWHUKDYLQJGHWHUPLQHWKHFRUUHFWHGUDWLR,,QWKHWULSSLQJWLPHDWƒ&LVGH¿QHG 1 000
    with the tripping curves (see page E-2 to page E-3). 500
    7RREWDLQWKHULJKWVHWWLQJRUWKHWULSSLQJWLPHDWDGLႇHUHQWWHPSHUDWXUHWKHUDWLR,,Q
    has to be corrected with the correction factor below:
    200
    100
    B
    50
    Correction factor table for thermal magnetic (TM-D) NSXm 20

    DB423008.eps
    to determine setting or tripping time at In 10
    5 TM125D : Im = 10 x In
    Rating Temperature °C t(s)
    2
    (A) In 10 15 20 25 30 35 40 45 50 55 60 65 70 1
    16 1.16 1.13 1.11 1.08 1.05 1.03 1.00 0.97 0.94 0.91 0.88 0.85 0.81 .5 TM160D :
    Im = 8 x In
    25 1.13 1.11 1.09 1.07 1.05 1.02 1.00 0.98 0.95 0.93 0.90 0.88 0.85 .2
    .1
    32 1.14 1.11 1.09 1.07 1.05 1.02 1.00 0.98 0.95 0.93 0.90 0.87 0.84
    .05
    40 1.15 1.12 1.10 1.08 1.05 1.03 1.00 0.97 0.95 0.92 0.89 0.86 0.83
    .02
    50 1.13 1.11 1.09 1.07 1.05 1.02 1.00 0.98 0.95 0.93 0.90 0.87 0.85 .01 t < 10 ms
    63 1.14 1.12 1.10 1.07 1.05 1.02 1.00 0.97 0.95 0.92 0.89 0.86 0.83 .005

    80 1.21 1.18 1.14 1.11 1.07 1.04 1.00 0.96 0.92 0.88 0.83 0.80 0.75 .002
    .001
    100 1.18 1.16 1.12 1.10 1.06 1.04 1.00 0.96 0.94 0.90 0.87 0.83 0.80 .5 .7 1 2 3 4 5 7 10 20 30 50 70 100 200 300
    125 1.17 1.14 1.11 1.08 1.06 1.03 1.00 0.96 0.93 0.90 0.87 0.84 0.80 I / Ir

    160 1.17 1.15 1.12 1.09 1.06 1.03 1.00 0.97 0.93 0.90 0.87 0.83 0.79

    Doing the right setting depending of the temperature:


    Example: What is the setting to obtain a real Ir of 105 A, taking into account the
    temperature, for a Compact NSXm 125 A?
    The necessary dial setting, in amperes, is shown below.
    b At 40 °C, Ir = 105 / 1 = 105 A
    b At 20 °C, Ir = 105 / 1.11 = 95 A
    b At 60 °C, Ir = 105 / 0.87 = 121 A.

    Calculating the tripping time at Ir = In for a given temperature:


    Example: What is the tripping time of a Compact NSXm 100A at Ir = In for an
    overload of 500 A?
    b At 40 °C, I/Ir = 5, tripping time is between 6 and 60 seconds
    b At 20 °C, I/Ir = 5 / 1.12 = 4.46, tripping time is between 8 and 80 seconds
    b At 60 °C, I/Ir = 5 / 0.87 = 5.75, tripping time is between 5 and 50 seconds

    For Ir = 0.7 to 0.9 In, additional correction factor need to be applied - please consult us.

    B-5

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