Table of Contents
Advertisement
4.14
Thermal Overload Protection
Setting Ranges / Increments
K-Factor per IEC 60255-8
Time Constant τ
Thermal Alarm Θ
Current Overload I
Extension kτ Factor when Machine
Stopped
Emergency Time T
Nominal Overtemperature (for I
Trip Characteristic
Formula for primary values:
Dropout Ratios
Θ/Θ
Trip
Θ/Θ
Alarm
I/I
Alarm
Tolerances
Referring to k · I
Referring to trip time
Influencing Variables Referring to k · I
Auxiliary DC voltage in range 0,8 ≤ V
Temperature in range –5 °C (41 °F) ≤ Θ
Frequency in range of 25 Hz – 70 Hz
Frequency in the range of 0.95 ≤ f/f
Frequency outside range 0.95 ≤ f/f
SIPROTEC, 7SK80, Manual
E50417-G1140-C344-A5, Release date 11.2012
th
/Θ
Alarm
Trip
for I
= 1 A 0.10 A to 4.00 A
Alarm
Nom
for I
= 5 A 0.50 A to 20.00 A
Nom
Emergency
)
Nom
Drops out with Θ
Approx. 0.99
Approx. 0.97
Nom
Nom
/V
Aux
amb
≤ 1.05 (f
Nom
≤ 1.05
Nom
0.10 to 4.00
1.0 min to 999.9 min
50% to 100% of the trip excessive temperature Increments 1 %
1.0 to 10.0 relative to the time constant for the
machine running
10 s to 15000 s
40 °C to 200 °C = –13 °F to +185 °F
Alarm
3 % or 15 mA for I
Nom
2 % class according to IEC 60255-8
3 % or 1 s for I/(k ·I
3 % class according to IEC 60255-8
≤ 1.15
AuxNom
≤ 55 °C (131 °F)
= 50 Hz or 60 Hz)
Nom
4.14 Thermal Overload Protection
Increments 0.01
Increments 0.1 min
Increments 0.01 A
Increments 0.1
Increments 1 s
Increments 1 °C
= 1 A, or 75 mA for I
Nom
) > 1.25;
Nom
1 %
0.5 %/10 K
1 %
Increased tolerances
Technical Data
= 5 A,
389
Advertisement
Table of Contents
