Danfoss VLT AQUA Drive FC 202 Design Manual page 19

Introduction
2.7.6 Cos φ Compensation
Generally speaking, the frequency converter has a cos φ of
1 and 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 shown in Illustration 2.6, a frequency converter does not
consume more than rated current.
800
700
600
500
400
300
200
100
1
0
0 12,5
Illustration 2.6 Current Consumption with a Frequency Converter
1 ®
VLT AQUA Drive FC 202
2 Star/delta starter
3 Soft-starter
4 Start directly on mains
Table 2.6 Legend to Illustration 2.6
®
VLT AQUA Drive FC 202 Design Guide
4
3
2
25 37,5 50Hz
Full load
& speed
®
MG20Z102 - VLT is a registered Danfoss trademark
2 2
17