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3VT1 Molded Case Circuit Breakers up to 160 A
Circuit breakers · Switch disconnectors
2/15
Siemens LV 36 · 2008
2
■
Characteristics
Overcurrent releases, 3-pole version
Overcurrent releases are integrated in circuit breakers. Releases
cannot be demounted and exchanged.
Tripping characteristics
Circuit breakers are available with four types of tripping charac-
teristics. They are designated with the letters:
„L“ - lines
Protecting lines with low starting currents
„D“ - distribution
Protecting lines and transformers
„M“ - motor
Motor protection
„N“ - short-circuit release only
• 3VT1 circuit breakers with characteristic
„L“
have a given and
fixed rated current value. The circuit breakers are produced
with
I
n
values in a standardized current range from 40 A to 160
A (see „Ranges of overcurrent releases and their possible set-
tings“). Short-circuit releases are fixed at 4 x
I
n
.
• 3VT1 circuit breakers with characteristic
„D“
have the option
of setting to a reduced current in a range of approximately
0.75 ... 1
I
n
. The circuit breakers are produced with
I
n
values
in a standardized current range from 16 A to 160 A (see
„Ranges of overcurrent releases and their possible settings“).
The short-circuit release is adjustable.
Setting values are given in the table on page 2/16.
• 3VT1 circuit breakers with characteristic
„M“
have the option
of setting a reduced current in a range of approximately 0.75
... 1
I
n
. The circuit breakers are produced with
I
n
values in a
standardized series of currents from 16 A to 100 A (see
„Ranges of overcurrent release and their possible setting“).
The short-circuit release is fixed at the value of 10 x
I
n
.
• 3VT1 circuit breakers with characteristic
„N“
only have a
circuit release. They are produced with
I
n
values in a stan-
dardized series of currents ranging from 32 A to 160 A. The
short-circuit release is adjustable.
The values are given in the table on page 2/16.
The type designation for the circuit breakers is set according
to the requested rated current and protection characteris-
tics.
For example: Motor protection with
I
n
= 32 A.
The order No. designation will be 3VT1 703-3DM36-0AA0.
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 2/16.
Setting of tripping characteristics
Circuit breakers with characteristic
„L“
„M“
„D“
NSO0_00502
t
I
L
I
NSO0_00048
t
I
L
I
I
r
NSO0_00500
t
I
L
I
I
r
I
i