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17/172 NZM circuit-breakers
Temperature dependency, derating
2010 CA08103002Z-EN
www.eaton.comTemperaturedependency,derating
Response time of the overload release at temperatures deviating from the reference
temperatures
Device part no.
Release type
Temperature compensation coefficient
20 °C
30 °C
40 °C
50 °C
60 °C
65 °C
70 °C
Thermomagnetic release (TM)
System protection
System protection (reference temperature 40 °C)
NZM…1(-4)-A(F)15…80(-NA)
TM
1.14
1.07
1
0.93
0.86
0.83
0.79
NZM…1(-4)-A(F)90…125(-NA)
TM
1.14
1.07
1
0.93
0.86
0.83
0.79
NZM…1(-4)-A160
TM
1.08
1.04
1
0.96
0.92
0.90
0.88
NZM…1-A20…125-SVE
TM with SVE
1.14
1.07
1
0.93
0.86
0.83
0.79
NZM…2(-4)-A(F)15…200(-NA)
TM
1.04
1.02
1
0.98
0.96
0.95
0.94
NZM…2(-4)-A(F)250(-NA)
TM
1.04
1.02
1
0.98
0.96
0.95
0.94
NZM…2(-4)-A20…200-SVE
TM with SVE
1.04
1.02
1
0.98
0.96
0.95
0.94
NZM…2(-4)-A250-SVE
TM with SVE
1.04
1.02
1
0.98
0.96
0.95
0.94
NZM…3(-4)A-250…500
TM
1.12
1.06
1
0.94
0.88
0.85
0.82
NZM…3(-4)A-250…500
TM with XAV
1.06
1
0.94
0.88
0.82
0.79
0.76
Short-circuit/motor protection
Motor protection (reference temperature 20 °C)
NZM…1-M(S)40…80(-CNA)
TM
1
0.98
0.95
0.93
0.90
0.89
0.88
NZM…1-M(S)100(-CNA)
TM
1
0.98
0.95
0.93
0.90
0.89
0.88
NZM…1-M(S)40…100-SVE
TM with SVE
1
0.98
0.95
0.93
0.90
0.89
0.88
NZM…2-M(S)20…200(-CNA)
TM
1
0.98
0.96
0.94
0.92
0.91
0.90
NZM…2-M(S)20…200-SVE
TM with SVE
1
0.98
0.96
0.94
0.92
0.91
0.90
NZM…3-S250…500
TM with/without XAV 1
1
1
1
1
1
1
Notes
If temperatures deviate from the reference temperature, a slight change of the overload protection properties occurs.
To determine the response time from the tripping characteristics, the temperature compensation coefficients listed in
the table must be considered.
Example:
An NZM1-A100 is calibrated for a reference temperature of 40 °C.
What happens when it is operated at an ambient temperature of 60 °C ?
At 60 °C, the temperature compensation coefficient of 0.86 results in a reduced operating current of I
r
= 100
A x 0.86 = 86 A. In other words at an ambient temperature of 60 °C the NZM1-A100 trips as if it were set to 86 A.
Reduction of the rated operational current (derating) under particular ambient conditions
(according to IEC 947)
Device part no.
Release type
Derating coefficient
20 °C
30 °C
40 °C
50 °C
60 °C
65 °C
70 °C
Thermomagnetic release (TM)
System protection
System protection (reference temperature 40 °C)
NZM…1(-4)-A(F)15…80(-NA)
TM
1
1
1
1
1
1
1
NZM…1(-4)-A(F)90…125(-NA)
TM
1
1
1
1
0.86
0.83
0.8
NZM…1(-4)-A160
TM
1
1
1
0.95
0.9
0.85
0.8
NZM…1-A20…100-SVE
TM with SVE
1
1
1
1
1
1
1
NZM…1-A125-SVE
TM with SVE
1
0.92
0.87
0.81
–
–
–
NZM…2(-4)-A(F)15…200(-NA)
TM
1
1
1
1
1
1
1
NZM…2(-4)-A(F)250(-NA)
TM
1
1
1
1
0.9
0.85
0.8
NZM…2(-4)-A20…200-SVE
TM with SVE
1
1
1
1
1
1
1
NZM…2(-4)-A250-SVE
TM with SVE
1
0.97
0.92
0.87
0.81
–
–
NZM…3(-4)A-250…500
TM
1
1
1
0.94
0.88
0.85
0.82
NZM…3(-4)A-250…500
TM with XAV
1
1
0.94
0.88
0.82
0.79
0.76
Short-circuit/motor protection
Motor protection (reference temperature 20 °C)
NZM…1-M(S)40…80(-CNA)
TM
1
1
1
1
1
1
1
NZM…1-M(S)100(-CNA)
TM
1
1
1
1
0.86
0.83
0.8
NZM…1-M(S)40…100-SVE
TM with SVE
1
0.92
0.87
0.81
–
–
–
NZM…2-M(S)20…200(-CNA)
TM
1
1
1
1
1
1
1
NZM…2-M(S)20…200-SVE
TM with SVE
1
1
1
1
1
1
1
NZM…3-S250…500
1
1
1
0.94
0.88
0.85
0.82
NZM…3-S250…500
TM with XAV
1
1
1
0.94
0.88
0.85
0.82
NZM…3-S250…400
TM
1
1
1
1
1
1
1
NZM…3-S250…400
TM with XAV
1
1
1
1
1
0.97
0.94
Notes
In determining the maximum permissible current loads at different ambient temperatures, the derating coefficients
listed in the table must be considered.
Example:
An NZM2-A250 should be operated at an ambient air temperature of 65 °C.
How high is the permissible rated operational current I
e
?
At 65 °C the derating coefficient is 0.85, i.e. I
e
= 250 A × 0.85 = 212.5 A.
At an ambient temperature of 65 °C the NZM2-A250 can therefore be operated at up to I
e
= 212.5 A.
NZM...A(F), NZM...M(S)