Siemens SENTRON 3VL160X System Manual page 147

Plug-in or withdrawable version:
Table 11- 21 Derating factors for electronic trip units (plug-in or withdrawable version)
Molded
case circuit
breaker
VL160
VL250
VL400
VL630
VL800
VL1250
VL1600
Example for VL250:
● I
● Ambient temperature = 60 °C
1. Fixed-mounted version:
2. Plug-in or withdrawable version:
Derating factor from the table "Derating factors of electronic trip units (fixed mounting)"
1)
Coefficient for plug-in or withdrawable version from the table "Derating factors for
2)
electronic trip units (plug-in or withdrawable version)"
3VL IEC molded case circuit breakers
System Manual, 11/2013, 110 0110 - 02 DS 03
Release
ETU
From [A]
63
125
200
315
--
--
1000
--
= 250 A at 50 °C
n
I = 250 x 0.95 = 237 A
1)
n
Set I to the next lowest value -> I
R
I = 250 x 0.95 x 0.9
1) 2)
n
-> Calculation of overall derating = 0.95 x 0.9 = 0.885
-> Set I to the next lowest value -> I
R
To [A] 40 °C
100 1
160 1
250 1
400 1
630 1
800 1
1250 1
1600 1
= 0.95 = 237 A
R
= 213 A
= 0.8 = 200 A
R
Technical data
11.4 Derating factors
Coefficient
at
50 °C 60 °C
1 1
0,9 0,9
0,9 0,9
0,9 0,9
0,85 0,85
0,9 0,9
0,95 0,95
0,8 0,8
70 °C
1
0,9
0,9
0,9
0,85
0,9
0,95
0,8
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