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Siemens IK PI · 2015
AS-Interface
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Motor starters for use in the field, high degree of protection
SIRIUS MCU motor starters for AS-Interface
> General data
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Overview
Portfolio of the SIRIUS 3RK43 MCU motor starter family
The SIRIUS MCU motor starter family (MCU = Motor Control
Unit) rounds off the bottom end of the SIRIUS motor starter
range.
This series of motor starters in a high degree of protection is a
system solution for the cabinet-free controlling of AC loads in the
field.
The MCU product range extends from I/O-controlled motor
starters – addressing a central sub-distribution board via
I/O stations – in a plastic enclosure for simple applications to
motor starters with AS-i communication in a rugged metal
enclosure for demanding tasks.
(For complete range, see Catalog IC 10
Motor Starters for Use
in the Field, High Degree of Protection)
The MCU motor starters are completely pre-wired inside, have a
high degree of protection and are designed for switching and
protecting any AC loads. They are mostly used on standard
three-phase motors in direct or reversing duty up to 5.5 kW at
400/500 V AC (electromechanical switching) and 400/460 V AC
(electronic switching).
The motor and short-circuit protection integrated in the MCUs
consists either of an electromechanical controlgear assembly or
solid-state overload protection and a motor starter protector unit
for short-circuit protection.
MCUs with metal enclosure are designed for the switching of
three-phase motors. Integrated control of the electrically oper-
ated motor brake with a braking voltage of
230 V AC or 400 V AC
is a standard feature. The
braking voltage is routed to the motor
over the motor cable.
SIRIUS MCU motor starters have the following main features:
•
Direct-on-line or reversing starters
•
Up to 5.5 kW
•
High degree of protection, namely IP55 on MCU motor starters
in a plastic enclosure and IP54 on motor starters in a metal en-
closure, enables distributed configurations in the field and
saves space in the control cabinet
•
Electromechanical or electronic switching
•
Easy and user-friendly control and monitoring through
AS-Interface bus communication
•
Controlled stopping through 230 V AC brake control or 400 V
AC for motor brake
•
Integrated lockable repair switch
•
Comprehensive motor protection thanks to integrated over-
load and short-circuit protection with SIRIUS 3RV motor starter
protectors or integrated solid-state overload relays (solid-state
starters)
•
Overload protection with thermal release (bimetal) or solid-
state overload relay with wide range setting
•
Power and load connection by means of an M screw
•
Main power loop possible (daisy chain; max. 2 x 6 mm
2
)
•
Robust and widely used M12 connection method for digital
inputs and outputs to connect I/O stations and the AS-i bus
connection increase flexibility and prevent errors in the system
configuration.
•
The LEDs (for AS-i bus connection) can provide comprehen-
sive diagnostics of the device on the spot.
•
Simple mounting for AS-i and external auxiliary voltage
(24 V DC) over an M12 connection
•
Manual operation: An integrated key-operated switch "MAN-0-
AUTO" and a selector button for switching on, switching off
and changing the direction of rotation for control purposes
during commissioning or maintenance
MCU motor starters with AS-i bus connection
in a plastic enclosure
This motor starter version offers an economical solution for
controlling and monitoring conveyor belts, pumps, fans or com-
pressors.
On this MCU the control commands and the status queries are
sent over the AS-i bus. The yellow cable (bus) and the black
AS-i cable for 24 V DC AUX are connected through an M12 plug.
The transparent enclosure top permits monitoring of the status
LEDs. These MCUs come completely pre-wired inside.
MCU motor starters with AS-i bus connection
in a metal enclosure for electromechanical or electronic
switching
These MCUs with their rugged metal enclosure in degree of pro-
tection IP54 are ideal in particular for controlling and monitoring
three-phase motors in harsh ambient conditions such as are
often found in conveyor systems.
A special feature of this version is the manual local operation of
the motor starter.
The key-operated switch "MAN-0-AUTO" for selecting Manual,
0 or Automatic mode prevents unauthorized changes of operat-
ing mode. In automatic mode the MCU is controlled through the
AS-i bus.
In manual mode a selector button is used for switching on,
switching off and changing the direction of rotation.
The status/diagnostics LEDs fitted to the cover indicate the
current operating state of the motor starter.
Unlike the electromechanical starter, the electronic motor starter
has wear-free solid-state switching devices which guarantee a
high switching frequency.
Another highlight of the electronic switching version is the solid-
state overload relay for motor protection, which has a wide
setting range for the motor current.
3RK4320-3.R51-.BA0
3RK4320-3.Q54-.BA.
3RK4320-5.Q64-.BA.
© Siemens AG 2014