User Manual

Product description
3.2 Basic physical principles of a three-phase induction motor
SIRIUS 3RW30 / 3RW40
Manual, 10/2010, 535199502000 DS 03
17
Starting torque
The starting torque and the breakdown torque can usually be assumed to be between two
and four times the rated torque. From the point of view of the load machine, this means that
the starting and acceleration forces exert a higher mechanical load on the machine and the
product being conveyed compared to nominal operation.
Disadvantages
This results in the following disadvantages
● A higher load is placed on the machine's mechanical components
● The costs for replacing worn parts and maintaining the application are higher
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Figure 3-2 Typical starting torque characteristic of a three-phase induction motor
Remedy
The SIRIUS 3RW30 and 3RW40 electronic soft starters allow the current and torque
characteristics during starting to be optimally adapted to the requirements of each
application.