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3RW3 semiconductor motor control unit
SIRIUS System Manual
GWA 4NEB 430 0999-02b
8-17
Figure 8-9: Load and motor torques and motor terminal voltage for operation with soft starter
Criteria for selection
Note
In the case of the SIRIUS 3RW30/31 soft starters, the corresponding soft
starter must be selected on the basis of the rated current for the motor (the
rated current of the soft starter must be
≥
the rated current for the motor).
The 3 potentiometers on the starter are for setting the starting voltage, the
starting time, and the coasting-down time.
The soft starter is correctly set when the motor starts smoothly and runs up
rapidly to its rated speed.
Ramp times of up to 20 seconds can be set.
U
e
t
t
R
U
S
U
M
M
starting
M
starting
with
M
motor
M
load
n
M
motor
with
SIRIUS3R soft starter
SIRIUS3R
Soft starter
M
B
M
B
= accelerating torque
of the motor