Device functions
7.2 Startup modes
3RW44 soft starters
126
Manual, 03/2017, NEB535219502000/RS-AB/008
Ramp-up detection
The soft starter features internal run-up recognition. If it detects a motor ramp-up, the motor
voltage is immediately increased to 100% of the line voltage. The internal bypass contacts
close and the thyristors are bridged.
Figure 7-5
Current limiting with soft starter
Typical applications for current limiting
Current limiting is used for applications with a large centrifugal mass (mass inertia) and
therefore long starting times, e.g. large fans, to reduce the load on the power supply system.