Introduction; Basic Physical Principles Of The Three-Phase Asynchronous Motor And Operating Principle Of The Soft Starter; Three-Phase Asynchronous Motor - Siemens 3RW44 Manual

Introduction

2.1 Basic physical principles of the three-phase asynchronous motor
and operating principle of the soft starter
2.1.1

Three-phase asynchronous motor

Application areas of the three-phase asynchronous motor
Three-phase asynchronous motors are used in a wide range of applications in commerce,
industry and trade owing to their simple, rugged design and their low-maintenance operation.
Problem
If a three-phase asynchronous motor is started directly, its typical current and torque
characteristics can cause disturbances in the supply system and the load machine.
Starting current
Three-phase asynchronous motors have a high direct starting current I
the motor version it can amount to between three times and fifteen times the rated
operational current. Seven to eight times the rated motor current can be taken as a typical
value.
12
(startup)
Manual, 03/2017, NEB535219502000/RS-AB/008
2
. Depending on
3RW44 soft starters