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3VT3 Molded Case Circuit Breakers up to 630 A
Circuit breakers · Switch disconnectors
4/3
Siemens LV 36 · 2008
4
■
Overview
The circuit breakers consist of a 3- or 4-pole switching unit and
an overcurrent release which is available with a choice of differ-
ent characteristics. The switch disconnector is equipped with a
switch disconnector module in place of the overcurrent release.
Switching units
The switching unit includes:
• Two 3VT9 300-4TA30 connecting sets – for connecting
busbars or cable lugs
• 3VT9 300-8CE30 phase barriers
• A set of 4 installation bolts (M5 x 25)
• A conductor holder
The switching unit must be fitted with an overcurrent release (cir-
cuit breaker) or a 3VT9 363-6DT00 switch disconnector module
(switch disconnector)
In case the circuit-breaker is fed from below (input terminals 2,
4, 6; output terminals 1, 3, 5),
I
cu
does not change.
For maximum circuit breaker/switch disconnector loads in
accordance with the ambient temperature, see page 4/11.
Overcurrent releases
ETU LP – characteristic L (lines)
• protecting lines with low starting currents
• without
I
r
regulation
ETU DP – characteristic D (distribution)
• protecting lines and transformers
ETU MP – characteristic M (motor)
• direct protection for motors and generators
• suitable also for protecting lines and transformers
ETU MPS – characteristic M (motor) with
adjustable timing selectivity
• direct protection for motors and generators
• suitable also for protecting lines and transformers
• enables setting time delay of independent release to
0, 100, 200 or 300 ms
ETU DPN – characteristic D (distribution) with
N-pole protection
• protecting lines and transformers in TN-C-S and TN-S network
For the description of releases, see page 4/16.
Auxiliary switches and auxiliary releases
As an option, the circuit breakers can be equipped with
• Auxiliary switches
• Alarm switches
• Shunt release for remote tripping
• Undervoltage release for protecting motors and other equip-
ment against damage in case of undervoltage.
Mounting
In the standard fixed-mounted design, the switching units can
be mounted onto support plates. As an option, the units are
available in plug-in or withdrawable versions
(see page 4/8)
.
Connection
Main circuit
• Is connected using Cu or Al busbars or cables, and possibly
cables with cable lugs
• For further connecting options, connecting sets can be used
(see page 4/9)
• Generally, conductors from the power supply are connected
to input terminals 1, 3, 5, (N) and conductors from the load to
terminals 2, 4, 6, (N). It is possible to reverse the current flow
inside the unit (i. e. infeed from below) without reducing the
rated short-circuit ultimate breaking capacity
I
cu
.
• In case of infeed from below, the units must be fitted with
3VT9 300-8CE30 phase barriers also on the side of terminals
2, 4, 6.
• We recommend painting the connecting busbars.
• Input and output conductors/busbars must be mechanically
reinforced to avoid transmitting electrodynamic forces to the
circuit breaker/switch disconnector during short-circuiting
• When connecting the main circuit, the dimensions of the
deionization space of the circuit breaker must be observed,
depending on the type of connection
(see page 4/43)
.
Auxiliary circuits
• Auxiliary switches, shunt releases or undervoltage releases
are connected using flexible 0.5 ... 1 mm
2
Cu conductors to
terminals on these devices.
• The motorized operating mechanism and auxiliary circuits of
the plug-in or withdrawable version are connected using a
connector.
For recommended cross-sections of cables, busbars and flexi-
bars for fixed-mounted, plug-in and withdrawable designs, see
page 4/11.