Current Limits For Load Monitoring - Siemens 3RW44 Manual

Typical applications for the slow speed function
This function is suitable for applications with a low counter-torque, e.g. positioning of
machine tools.
Note
In addition to the set parameters, motor-specific characteristics and the connected load
influence the speed resulting from the slow speed function and the slow speed torque
generated in the motor.
Note
For operation of the motor with the specified slow speed parameters, the "slow speed"
function must be assigned to one control input, and the "Motor CW PS1/2/3" or "Motor CCW
PS1/2/3" function must at the same time be assigned to the other. See also the circuit
suggestion in chapter Typical circuit diagrams (Page 216).
Directions of rotation:
Right (CW): Rotation in line phase direction
Left (CCW): Rotation contrary to the line phase direction
Note
Due to the reduced motor speed and the related reduced self-cooling of the motor, this mode
is not recommended for continuous operation.
Risk of property damage
For optimum motor protection, use the combination of electronic motor overload protection
and evaluation of a temperature sensor installed in the motor.
7.5

Current limits for load monitoring

Low and high current limits can be set so that a message can be issued if they are exceeded
or undershot.
Lower current limit
The lower current limit could be used, for example, to indicate tearing of a V belt and the
associated no-load current of the motor or if the filter of the fan is clogged.
Upper current limit
The upper current limit can be used to determine increased power loss in the application, for
example caused by bearing damage.
3RW44 soft starters
Manual, 03/2017, NEB535219502000/RS-AB/008
CAUTION
Device functions
7.5 Current limits for load monitoring
135