Siemens SENTRON 3VL series - Page 147

Technical data
11.4 Derating factors
3VL IEC molded case circuit breakers
System Manual, 11/2013, 110 0110 - 02 DS 03
147
Plug-in or withdrawable version:
Table 11- 21 Derating factors for electronic trip units (plug-in or withdrawable version)
Molded
case circuit
breaker
Release
ETU
Coefficient
at
From [A]
To [A]
40 °C
50 °C
60 °C
70 °C
VL160 63
125
100
160
1
1
1
0,9
1
0,9
1
0,9
VL250
200
250
1
0,9
0,9
0,9
VL400
315
400
1
0,9
0,9
0,9
VL630
--
630
1
0,85
0,85
0,85
VL800
--
800
1
0,9
0,9
0,9
VL1250
1000
1250
1
0,95
0,95
0,95
VL1600
--
1600
1
0,8
0,8
0,8
Example for VL250:
● I
n
= 250 A at 50 °C
● Ambient temperature = 60 °C
1. Fixed-mounted version:
I
n
= 250 x 0.95
1)
= 237 A
Set I
R
to the next lowest value -> I
R
= 0.95 = 237 A
2. Plug-in or withdrawable version:
I
n
= 250 x 0.95
1)
x 0.9
2)
= 213 A
-> Calculation of overall derating = 0.95 x 0.9 = 0.885
-> Set I
R
to the next lowest value -> I
R
= 0.8 = 200 A
1)
Derating factor from the table "Derating factors of electronic trip units (fixed mounting)"
2)
Coefficient for plug-in or withdrawable version from the table "Derating factors for
electronic trip units (plug-in or withdrawable version)"