49 Thermal Overload Protection
Reference
Parameter
Value
I
set
Overload setting
0.1 to 3 ⋅ I
rated
, Δ 0.01 I
rated
T
th
Time constant setting
0.5 to 1000 min, Δ 0.5 min
Operate and Reset Level
Attribute
Value
I
op
Operate level
I
set
: ± 5 % or ± 1 % I
rated
Reset level
≤ 95 % I
op
Repeatability
± 1 %
Variation IEC
60255-1
-10 °C to +55 °C
≤ 5 %
f
rated
± 5 %
≤ 5 %
Operate and Reset Time
Attribute
Value
t
op
Overload trip operate time
(min)
± 5 % or ± 100 ms, (I
set
: 0.3 to 3
⋅ I
rated
)
I = Average rms current
I
p
= Pre‑load current
I
θ
= Thermal overload setting
current
τ = Thermal heating time
constant (minutes)
ln = Natural logarithm
t = Operate time (minutes)
Repeatability
± 100 ms
Current
(multi-
ples of
setting
)
Operate time t for various time constraints (s)
0.5 min 1 min
2 min
3 min
5 min
10 min 15 min 20 min 30 min 50 min 100
min
1.2
35.57
71.14
142.27 213.41 355.69 711.37 1067.0
6
1422.7
5
2134.1
2
3556.8
7
7113.7
4
1.5
17.63
35.27
70.53
105.8
176.34 352.67 529.01 705.34 1058.0
2
176..36 3526.7
2
2
8.63
17.26
34.52
51.78
86.3
172.61 258.91 345.22 517.83 863.05 1726.0
9
2.5
5.23
10.46
20.92
31.38
52.31
104.61 156.92 209.22 313.84 523.06 1046.1
2
3
3.53
7.07
14.13
21.2
35.33
70.67
106
141.34 212.01 353.35 706.7
3.5
2.55
5.11
10.22
15.33
25.55
51.09
76.64
102.19 153.28 255.47 510.95
4
1.94
3.87
7.74
11.62
19.36
38.72
58.08
77.45
116.17 193.62 387.23
4.5
1.52
3.04
6.08
9.12
15.19
30.39
45.58
60.77
91.16
151.93 303.86
5
1.22
2.45
4.9
7.35
12.25
24.49
36.74
48.99
73.48
122.47 244.93
5.5
1.01
2.02
4.03
6.05
10.08
20.17
30.25
40.34
60.51
100.85 201.7
10.11
Technical Data
10.11 49 Thermal Overload Protection
470
Reyrolle 7SR5, Transformer Protection Device, Device Manual
C53000-G7040-C015-1, Edition 11.2019