Siemens VT250 Operating Instructions Manual - Page 9
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Operating Instructions
(9)
Test button
Setting the long-time delay overload (L) and short-circuit instantaneous (I) protection
For the VT630 circuit breaker, there are different versions available:
- L protection fixed (I
= 1.0 x I
r
- L protection adjustable (I
r
Figure (19). The ranges of current settings are described in Table (20).
- ETU, LSI adjustable I
= 0.4 - 1.0 x I
r
Load capacity at various ambient temperatures
The permissible load capacity of the circuit breaker is dependent on the ambient temperature in its immediate vicinity, see Table (18).
In the case of thermal magnetic ETUs, the load is independent of the temperature.
(18)
Rated current
Ambient temperature
of frame size
I
+10 °C +20 °C +30 °C +40 °C +50°C +55 °C +60 °C
n
630 A
1.12
(19) VT630 front of ETU
Current beam
indication of operation
Socket for
test kit
Alarm indication
of fault
Indication of power
and self-diagnosis
A5E00817858-01
4-pole version
) and I protection fixed.
n
= 0.7 - 1.0 x I
) and I protection fixed. An illustration of the trip unit with adjustable L can be seen in
n
n
1.1
1.03
1.0 I
n
Switch for current settings I
ON
TRIP
RESET
(OFF)
0.9
0.85
0.8
Switch for long-time delay
setting I
r
Switch for ground fault current setting
(only available for 4-pole versions)
Switch for pre-alarm setting I
, I
sd
i
Characteristic curve
LC
of overcurrent
English
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