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3VT2 Molded Case Circuit Breakers up to 250 A
Accessories and Components
Motorized operating mechanism
3/31
Siemens LV 36 · 2008
3
■
Design
The motorized operating mechanism is part of circuit breaker
accessories enabling you to switch the circuit breaker on and off
remotely. Modular design of the operating mechanisms enables
simple mounting on the circuit breaker (also additionally) after
the circuit breaker accessory compartment cover is removed.
The fixed operating mechanism can be sealed. 3VT circuit
breakers with motorized operating mechanisms can be used in
the most demanding industrial applications such as protection
of standby sources, synchronization of two sources, etc. and for
all applications for which it is necessary to ensure automated
and unmanned operation of electrical equipment.
The motorized operating mechanisms are equipped with spring
storage mechanisms and due to accumulated energy to trip the
circuit breaker, it is no problem to trip the circuit breakers within
times up to 50 ms. Releasing of the storage unit and tripping of
the circuit breaker is ensured by a closing coil that belongs to
standard equipment of every motorized operating mechanism.
The time before the circuit breaker is tripped using the operating
mechanism is 800 ms. This method of tripping is suitable for
controlling technological entities. When faster circuit breaker
tripping is required (e.g. emergency STOP button), it is possible
to use the motorized operating mechanism in combination with
undervoltage release or shunt release.
• On the front panel of the motorized operating mechanism,
there is a selector switch to select the drive modes with a pos-
sibility to indicate remotely the selector switching position. The
first mode is automatic remote control (selector switch in
AUTO position). This is the standard position in automatic op-
eration. The second mode is manual control (selector switch
in MANUAL position), the motorized operating mechanism
does not need any voltage to perform its function.
• Remote switching on and off in position AUTO is carried out
using pushbuttons that must be connected to the operating
mechanism connector. Furthermore, this position makes it is
possible to control the circuit breaker with the pushbuttons on
the operating mechanism front panel.
• In MANUAL mode it is possible to switch on and off using the
green and red pushbuttons on the front panel of the motorized
operating mechanism cover. The function of the remote con-
trol ON button in MANUAL mode is locked up, whereas the
function of the remote control OFF button remains active for
safety reasons.
• The motorized operating mechanism, apart from the circuit
breaker, recognizes only two fixed positions. In the first posi-
tion, the circuit breaker is ON. When the circuit breaker is
tripped in AUTO mode by overcurrent releases or auxiliary
trips. Then, because of the mechanical link between the circuit
breaker and the operating mechanism, a pulse will be gener-
ated to wind up the spring of the storage unit automatically.
The operating mechanism can be wound up automatically,
depending on the demand by the operator, by permanent
closing of switch S or after the circuit breaker is checked by
switching S switch on. In the second fixed position the circuit
breaker is switched off and the loaded operating mechanism
is ready to switch the breaker on after it has received the set-
ting pulse.
• The motorized operating mechanism makes it possible to con-
trol the circuit breaker after the loss of control voltage. In MAN-
UAL and AUTO modes, it is possible to wind up the storage
unit by repeated rotation of the foldable handle. After the stor-
age unit is wound up, it is possible to switch the circuit breaker
on and off using the control buttons on the front panel of the
operating mechanism.
• On the front panel, there is a storage unit status indicator indi-
cating locally what state the operating mechanism storage is
in and whether it is possible to switch the circuit breaker on.
3VT3 motorized operating mechanisms enable to obtain a
storage status signal from the terminal strip also remotely.
3VT2 operating mechanisms have optional designs, alterna-
tively with MANUAL/AUTO indication.
• The operating mechanism can be furnished with an electro-
mechanical operations counter that may be installed in the op-
erating mechanism cover or fixed beyond the circuit breaker
space (e.g. in the switchgear cabinet door) or in the switch-
gear space using a metal holder included in the supply of ex-
ternal operations counter and its connecting can be done us-
ing connectors.
• The operating mechanism can be locked in off position using
as many as three padlocks with shank diameter of maximum
4.3 mm.
• An 3VT9 300-3MF20 cover can be fitted to the turn-on switch
of the operating mechanism and then sealed. The cover pre-
vents turning on the circuit breaker from the operating mech-
anism panel.
• The 3VT9 300-3MF00 extension cable has a connector on one
side that connects to the connector on the motorized operat-
ing mechanism and conductors on the other side that con-
nect, for example, to a terminal block.
1)
For sequence of control pulses, see page ...
Order No.
3VT9 200-3M..0
Operational voltage U
e
V AC 24, 48, 110, 230, 400, 500
DC 24, 48, 110, 220
Rated frequency f
n
Hz 50/60
Control pulse length for storing
ms 400 ...
∞
1)
Control pulse length
ms 20 ... 700
1)
, 400 ...
∞
1)
Time before switching on
ms < 50
Time before switching off
ms 800
Frequency of cycles ON/OFF
3 contact making/hr
Frequency of cycles -
instant successive ON/OFF cycles
10 contact making
Mechanical endurance
30000 contact making
Input power
AC
DC
100 VA
100 W
Protection
• AC 24, 48, 110 V; AC 230 V
LSN 4C/1; LSN 2C/1
• DC 24, 48, 110 V; DC 220 V
LSN-DC 4C/1; LSN-DC 2C/1
Rated operating current
AUTO/MANUAL switches
I
e
/U
e
V AC 5 A/250
DC 0.5A/250
Order No.
3VT9 300-3MF00
Number of conductors
12
Conductor cross sections S
mm
2
0.35
Conductor lengths
cm 60