Canceling the switch-on command (t
4
) activates the stopping mode and the motor is shut down.
The power semiconductors also ensure that the motor coasts down smoothly to a stop. As long
as the stopping time is active (t
4
to t
5
), power is still supplied to the motor. It may take longer for
the motor to actually coast down to a standstill (t
6
).
8>9@
8
H
21
581
%<3$66('
8
6
Q
H
Q>PLQ@
W>V@
W
W
W
W
W
W
①
Speed
t
5
End of the set stopping time
(t
5
-t
4
)
②
Voltage
t
6
Motor at standstill
t
1
Motor start-up with set starting voltage U
S
U
S
Set starting voltage
t
2
Rated operating speed n
e
reached
U
e
Rated operational voltage
t
3
End of the set ramp-up time
(t
3
-t
1
)
n
e
Rated operating speed of the motor
t
4
Switch-on command is canceled, motor is
switched off
Functions of the 3RW55 and 3RW55 Failsafe soft starters
Note the information in chapter Firmware update (Page 22).
• Parameterizable soft starting for a smooth drive start-up
• Parameterizable soft stopping for a smooth drive stop
• Parameterizable current limiting for avoiding current peaks
• Integrated electronic motor overload protection with adjustable trip class (OFF,
CLASS 10A, 10E, 20E, 30E)
• Integrated intrinsic device protection protects the 3RW55 and 3RW55 Failsafe soft starters
from overload
• Extended complete motor protection by means of thermistor motor protection for
connection of a temperature sensor
• Extended operating and diagnostic functions provided by the High Feature 3RW5 HMI
• Analog output for displaying a set measured value using an external evaluation unit
• Automatic parameterization simplifies system commissioning
Description
3.3 Operating principle
SIRIUS 3RW55 and 3RW55 Failsafe Soft Starters
26
Equipment Manual, 02/2022, A5E35630887002A/RS-AF/006
