Soft Starters In Inside Delta Circuits - Siemens SIRIUS 3RW44 User Manual

Installation, Connection and Branch Layout

3.2.3 Soft Starters in Inside Delta Circuits

Prerequisite
Example
3-6
A motor whose windings can be connected in a delta circuit where a line voltage
prevails.
Line voltage:
Rated motor current:
Current via soft starter in an inside delta circuit:
Selected soft starter in an inside delta circuit:
Figure 3-4: Name plate of a 22 kW motor
The SIRIUS 3RW44 soft starter can be dimensioned to match the current flowing
in the motor section (58 % of the conductor current) by connecting it to the delta
winding of the motor. This requires at least 6 motor lines.
The 3RW44 soft starter automatically detects how it is connected, meaning that
the connection type does not have to be explicitly set on the device. The
detected connection type can be read on the starter under the menu item "Status
display/Type of connection". In this case, the display reads "Inside delta circuit".
If the circuitry is faulty or the motor is not connected, the display shows
"Unknown".
Notice
The rated motor current given on the name plate must always be set in the quick
start menu or in the motor adjustment menu item. This setting is independent of
the type of connection of the soft starter.
Value to be set in the above example for a line voltage of 400 V, e.g. 40.5 A.
400 V
40.5 A
approx.
24 A
3RW44 22
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SIRIUS 3RW44 manual
GWA 4NEB 535 2195-02 DS 06