Iec Thermal Overload Protection Curve - DEMA CPM 310 G User Manual

IEC Thermal Overload Protection Curve

IEC Thermal Overload Protection formula and sample curves according to this formula are given below.
Formula characteristic is determined by the T
parameters are considered, it is calculated that CPM 310 G relay can run 1,540,000 unique IEC Thermal
Overload Protection curves; for its impossible to demonstrate all of the curves on a chart, sample curves are
given on the below chart to express an overview of the characteristic. □
t Trip time delay (minute).
T Thermal Constant (minute); setting range: (1-200) m, in 1m steps.
e
k Trip Threshold Translation Constant (-); setting range: (1.00-1.50), in 0.01 steps.
I RMS value of load current (A).
I Set current (A); setting range: (0.10-3.20) In, in 0.01I
θ
%θ Overload Pre-heating (%); setting range: (50-200) %, in 1% steps.
p
Overload Trip Threshold (%); setting range: (50-200) %, in 1% steps. □
%θ
trip
, k, I , %θ and %θ
e θ p trip
2
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( ) − %Θ
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log Θ
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e
2
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( ) − %Θ
[ �� × ��
Θ
steps.
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parameters. When setting ranges for these
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