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3VT1 Molded Case Circuit Breakers up to 160 A
Circuit breakers · Switch disconnectors
2/19
Siemens LV 36 · 2008
2
Overcurrent releases, 4-pole version
The overcurrent release is an integral part of the circuit breaker.
It is not possible to deinstall or exchange the releases.
4-pole circuit breakers are manufactured in the following
versions:
• 3P+N (three poles protected, N-pole unprotected)
• 4P (all four poles protected)
The permissible load of the N-pole is 100%
I
n
.
Tripping characteristics
The circuit breakers are delivered with three types of tripping
characteristics designated by the following letters:
„L“ - lines
Protection of lines with low starting current
„D“ - distribution
Protection of lines and transformers
„N“ - short-circuit
Protection against short circuit only
• 3VT1 Circuit breakers with characteristic
„L“
have a fixed
value of rated current
I
(without
I
n
control). The circuit break-
ers are manufactured with
I
n
values of standard current range
40 ... 160 A, see „Ranges of overcurrent release and their
possible setting“. The Short-circuit release has a fixed setting
to 4 x
I
n
.
• 3VT1 circuit breakers with characteristic
„D“
can be set to a
reduced current in the range of approx. 0.75 ... 1
I
n
.
The circuit breakers are manufactured with
I
n
values within a
standard current range of 16 ... 160 A.
Setting values are given in the table on page 2/20.
• 3VT1 Circuit breakers with characteristic
„N“
have only a short
circuit release. They are manufactured with circuit breaker val-
ues within a standard current range of 32 ... 160 A. The Short
circuit release is adjustable.
The values are given in the table on page 2/20.
The type designation for the circuit breakers is set according
to the requested rated current and protection characteris-
tics.
For example.: Protection of a circuit with
I
n
= 40 A.
The order No. designation will be 3VT1 704-2EC46-0AA0.
Setting of tripping characteristics
•
Dependent release (thermal) L
(for circuit breakers with
characteristics “D” and “M”). The dependent release for over-
load protection
I
r
(instantaneous), is adjusted in a continuous
range using the
I
r
adjustment dial on the overload release. The
I
r
adjustment range is 0.75 ... 1
I
n
.
•
Independent instantaneous release (short-circuit relase) I
(for circuit breakers with characteristics “D” and “N”). With an
independent instantaneous release (value of the short circuit
current
I
i
), adjustment is possible within a continuous range.
All values are given in the table on page 2/20.
Setting of tripping characteristics
Circuit breakers with characteristic
„L“
„D“
„N“
NSO0_00502
t
I
L
I
NSO0_00500
t
I
L
I
I
r
I
i
NSO0_00216
t
I
L
I
I
i