Page 55 - Sace Emax 2 Manual for design engineers

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ABB | SACE Emax 2
L Protection Function
If the current of one or more phases exceeds threshold I1, the protection trips and, after a time established
t by the value read and by the parameter settings, transmits the TRIP command.
I1 L To check and simulate the trip times in relation to all the parameters, please consult:
• the summary table of the protections with the calculation formulas (page 92)
• the graph with trip curve (from page 95)
t1
Parameters
I Parameter Description Default
Establishes curve dynamics and trip time calculation:
• t = k / I according to IEC 60947-2.
2
• IEC 60255-151 SI
Curve t = k/I 2
• IEC 60255-151 VI
• IEC 60255-151 EI
• t = k / I according to 60255-151
4
Establishes the value that activates the protection and contributes
towards calculating the trip time.
Threshold I1 1 In
The value is given as both absolute value (A) and relative value (In) and
can be set within the range: 0.4 In to 1 In, in 0.001 In steps
Contributes towards calculating the trip time.
Time t1 The value is given in seconds and can be set within the range: 3 s .. 144 s
144 s, in 1 s steps
Activates/deactivates the thermal memory function (page 80)
Thermal NOTE:the function is available with curve t=k/I 2 OFF
memory

Warns that the measured current is near to protection activation
threshold I1.
The value is given in percentage of threshold I1 and can be set within
Prealarm I1 the range: 50% I1 to 90% I1, in 1% steps. 90 % I1
NOTE: the prealarm condition deactivates in two cases:
• current lower than prealarm threshold I1
• current higher than threshold I1

Limitations and additional functions
• threshold I1 must be lower than threshold I2 (if S protection is activated)
• the trip time of the protection is forcibly set at 1 s if the calculation results give a lower theoretical value
and/or if the current reading is more than 12 In
• with CB in UL standard configuration, the only available curve is t = k/I 2

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