4.21 Thermal Overload Protection
567
7SD5 Manual
C53000-G1176-C169-1
4.21 Thermal Overload Protection
Setting Ranges
Calculation Method
Tripping Characteristic
Dropout to Pickup Ratio
Tolerances
Factor k according to IEC 60255-8 0.10 to 4.00 Increments 0.01
Time Constant τ
th
1.0 min to 999.9 min Increments 0.1 min
Thermal Alarm Θ
Alarm
/Θ
Trip
50% to 100% of the trip overtem-
perature
Increments 1 %
Current Overload I
Alarm
for I
N
= 1 A 0.10 A to 4.00 A Increments 0.01 A
for I
N
= 5 A 0.50 A to 20.00 A
Calculation method temperature rise Maximum temperature rise of 3 phases
Average of temperature rise of 3 phases
Temperature rise from maximum current
Θ/Θ
Trip
Θ/Θ
Alarm
I/I
Alarm
Drops out with Θ
Alarm
Approx. 0.99
Approx. 0.97
Referring to k · I
N
2 % or 1 % of nominal current; Class 2 % according to
IEC 60255-8
Referring to tripping time 3 % or 1 s for I/(k ·I
N
) > 1.25; class 3 % acc. to IEC 60255-8
www . ElectricalPartManuals . com
To Next Page
Loading...
