Thermal Overload Protection - Siemens SIPROTEC Manual

Technical Data

4.23 Thermal Overload Protection

4.23 Thermal Overload Protection
Setting Ranges
Factor k according to IEC 60255-8
Time Constant τ
th
Thermal Alarm Θ /Θ
Alarm Trip
Current Overload I
Alarm
Calculation Method
Calculation method temperature rise
Tripping Characteristic
Dropout to Pickup Ratio
Θ/Θ
Trip
Θ/Θ
Alarm
I/I
Alarm
Tolerances
Referring to k · I
N
Referring to tripping time
626
0.10 to 4.00
1.0 min to 999.9 min
50 % to 100 % of the trip overtemperature Increments 1 %
for I = 1 A 0.10 A to 4.00 A
N
for I = 5 A 0.50 A to 20.00 A
N
Maximum temperature rise of 3 phases
Average of temperature rise of 3 phases
Temperature rise from maximum current
Drops out with Θ
Approx. 0.99
Approx. 0.97
2 % or 1 % of nominal current; Class 2 % according to
IEC 60255-8
3 % or 1 s for I/(k ·I
Alarm
) > 1,25; class 3 acc. to IEC 60255-8
N
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
Increments 0.01
Increments 0.1 min
Increments 0.01 A