User Manual

Functions
5.1 Start modes
SIRIUS 3RW30 / 3RW40
Manual, 10/2010, 535199502000 DS 03
31
Ramp-up detection (3RW40 only)
The SIRIUS 3RW40 soft starter is equipped with an integrated ramp-up detection function. If
it detects a motor startup, the motor voltage is immediately increased to 100 % of the mains
voltage. The internal bypass contacts close and the thyristors are bridged.
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Figure 5-4 Current limiting with soft starter
Typical applications for current limiting
Current limiting is used for applications with large centrifugal masses (mass inertias) and
therefore longer ramp-up times, e.g. fans, circular saws etc.