Torque Control And Pump Stop - Siemens SIRIUS 3RW44 User Manual

Device Functions

6.3.2 Torque Control and Pump Stop

Stopping time and
stopping torque
Pump stop
Typical applications for soft stop / pump stop
6-12
In "Torque-controlled stopping" and "Pump stop" mode, the coasting down /
natural run-down procedure of the load is extended. This function is set if abrupt
stopping of the load is to be prevented. This is typical in applications with small
mass reactances or high counter torques.
For optimum torque control during the stopping procedure, the motor data of the
motor connected to the soft starter should be entered in the selected parameter
set using the menu item "Setting".
The "Stopping time" parameter of the soft starter can be used to specify for how
long power should be fed into the motor after removal of the on command. Within
this stopping time, the torque generated in the motor is continuously and linearly
reduced to the set stopping torque and the application is smoothly stopped.
In pump applications, so-called water hammers can occur if the drive is stopped
abruptly without using pump stop. These water hammers are caused by the
sudden stall and the accompanying pressure deviations in the pump. They
cause noise and a mechanical impact on the piping system, as well as on the
flaps and valves it contains.
Motor
torque
M
M
Nominal operation
Stopping torque
Figure 6-7: Soft stop / pump stop
Use soft stop / pump stop
• in pumps to prevent water hammers.
• in conveyor belts to prevent materials from toppling.
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.
Stopping time
Stop command
at soft starter
Time (t)
s
SIRIUS 3RW44 manual
GWA 4NEB 535 2195-02 DS 06