
Thermal Overload Protection 49
Setting Ranges
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 overtemperature
Increments 1 %
Current alarm element
Ι
Alarm
for
Ι
Nom
= 1 A
0.10 A to 4.00 A
Increments 0.01 A
for
Ι
Nom
= 5 A
0.50 A to 20.00 A
Calculation Method
Calculation method temperature rise
Maximum temperature rise of 3 phases
Average of temperature rise of 3 phases
Temperature rise from maximum current
Trip Characteristic
Formula for primary values:
Trip Characteristic curve for
Ι
/ (k ⋅
Ι
Nom
) ≤8
with
t
Trip time in minutes
τ
th
Heating-up time constant
Ι
n
Actual load current
Ι
pre
Preload current
k
Setting factor per IEC 60255-8
Ι
Nom
Nominal current for the protected object
Drop-off to Pick-up Ratio
Θ/Θ
Trip
Θ/Θ
Alarm
Ι
/
Ι
Alarm
Drops out with Θ
Alarm
approx. 0.99
approx. 0.97
Tolerances
Referring to k ·
Ι
Nom
for
Ι
N
= 1 A
3 % or 15 mA, 2 % class according to IEC 60255-8
for
Ι
N
= 5 A
3 % or 75 mA, 2 % class according to IEC 60255-8
Referring to trip time
3 % or 1 s for
Ι
/(k ·
Ι
Nom
) > 1.25, 3 % class according to IEC 60255-8
4.10
Technical Data
4.10 Thermal Overload Protection 49
276
SIPROTEC 4, 7SD80, Manual
E50417-G1100-C474-A2, Edition 02.2018
Содержание SIPROTEC 4 7SD80
Страница 8: ...8 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...
Страница 10: ...10 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...
Страница 18: ...18 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...
Страница 248: ...248 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...
Страница 298: ...298 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...
Страница 312: ...312 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...
Страница 322: ...322 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...
Страница 400: ...400 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...
Страница 402: ...402 SIPROTEC 4 7SD80 Manual E50417 G1100 C474 A2 Edition 02 2018 ...