Thermal Overload Protection - Siemens 7SC80 Manual

Technical Data

4.14 Thermal Overload Protection

4.14 Thermal Overload Protection
Setting Ranges / Increments
K-Factor accord. IEC 60255-8
Time Constant τ
Thermal Alarm Θ
Current Overload Ι
Extension kτ Factor when Machine Stopped
Emergency Time T
Nominal Overtemperature (for Ι
Trip Characteristic
Formula for primary values:
Trip Characteristic curve for Ι / (k ⋅ Ι
with
t Trip time in minutes
τ Heating-up time constant
th
Actual load current
Ιn
Preload current
Ι
pre
k Setting factor per IEC 60255-8
Nominal current for the protected object
Ι
Nom
Dropout Ratios
Θ/Θ
Trip
Θ/Θ
Alarm
Ι/Ι
Alarm
Tolerances
Referring to k · Ι
Referring to trip time
Influencing Variables Referring to k · Ι
Auxiliary direct voltage in the range of 0.8 ≤ V
Temperature in the range of 23.00 °F (-5 °C) ≤ Θ
Frequency in the range of 25 Hz to 70 Hz
Frequency in the range of 0.95 ≤ f/f
544
th
/Θ
Alarm Trip
for Ι = 1 A
Alarm Nom
for Ι = 5 A
Nom
Emergency
)
Nom
) ≤8
Nom
Drops out with Θ
approx. 0.99
approx. 0.97
for Ι = 1 A 3 % or 15 mA, 2 % class according to IEC 60255-8
Nom N
for Ι = 5 A 3 % or 75 mA, 2 % class according to IEC 60255-8
N
3 % or 1 s for Ι/(k ·Ι
Nom
≤ 1.05 (f
Nom
0.10 to 4.00
1.0 min to 999.9 min
50 % to 100 % of the trip excessive
temperature
0.10 A to 4.00 A
0.50 A to 20.00 A
1.0 to 10.0 relative to the time
constant for the machine running
10 s to 15000 s
40 °C to 200 °C
Alarm
) > 1.25, 3 % class according to IEC 60255-8
Nom
/V ≤ 1.15
PS PSNom
≤ 131.00 °F (55 °C)
amb
= 50 Hz or 60 Hz)
Nom
E50417-G1140-C486-A8, Edition 07.2017
Increments 0.01
Increments 0.1 min
Increments 1 %
Increments 0.01 A
Increments 0.1
Increments 1 s
Increments 1 °C
1 %
0.5 %/10 K
1 %
SIPROTEC Compact, 7SC80, Manual