Siemens SIRIUS 3RW44 Manual page 102

Device Functions
Stopping time
Typical applications for DC braking
6-16
Note
To control the motor with the specified slow speed parameters, "Slow speed"
must be assigned to one control input, and "Motor right PS1/2/3" or "Motor left
PS1/2/3" must be assigned to the other. Also refer to the circuit proposal in
Chapter 8.1.7.
Directions of rotation:
Right: rotation in line phase direction
Left: rotation counter-clockwise to the line phase direction
Caution
Due to the reduced motor speed and the accompanying reduced self-cooling of
the motor this operating mode is not recommended for contiuous operation.
Caution
Risk of damage to property.
For optimum motor protection use a combination of electronic motor overload
protection and evaluation of a temperature sensor integrated into the motor.
The stopping time determines how long braking torque is applied to the motor.
The braking time should be long enough to bring the load to a complete
standstill.
To achieve a sufficient braking effect until standstill, the load's mass moment of
inertia should not be higher than 5 times the motor's mass moment of inertia.
≤ 5 x J
(J ).
Load Motor
The soft starter has no standstill recognition; if required, this must be
accomplished using external measures.
Motor
torque (M)
M
Nominal
DC braking torque
Motor braking
torque
Fig. 6-10: DC braking
Use "DC braking" in lathes (e.g. for tool changeover) or disk saws.
Stopping time
Stop command
at soft starter
Time
s
SIRIUS 3RW44 manual
GWA 4NEB 535 2195-02 DS 02