Danfoss VLT AQUA Drive Design Manual page 19

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VLT AQUA Drive Design Guide
2.7.6. Cos φ compensation
Generally speaking, a frequency converter with a cos φ of 1 provides power factor correction for the cos φ of the motor, which means that there is no
need to make allowance for the cos φ of the motor when sizing the power factor correction unit.
2.7.7. Star/delta starter or soft-starter not required
When larger motors are started, it is necessary in many countries to use equipment that limits the start-up current. In more traditional systems, a star/
delta starter or soft-starter is widely used. Such motor starters are not required if a frequency converter is used.
As illustrated in the figure below, a frequency converter does not consume more than rated current.
1 = VLT AQUA Drive
2 = Star/delta starter
3 = Soft-starter
4 = Start directly on mains
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MG.20.N4.02 - VLT is a registered Danfoss trademark
2. Introduction to VLT AQUA Drive
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