Danfoss VLT FC 102 Series Design Manual page 27

Introduction to VLT® HVAC D...
2.7.7 Cos φ Compensation
®
Generally speaking, the VLT
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.
2.7.8 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 an adjustable frequency drive is used.
As illustrated in Figure 2.14, an adjustable frequency drive
does not consume more than rated current.
800
700
600
500
400
300
200
100
1
0
0 12,5
Figure 2.14 An Adjustable Frequency Drive Does Not
Consume More Than Rated Current
®
1 VLT HVAC Drive
2 Star/delta starter
3 Soft-starter
4 Start directly on line power
Table 2.8 Legend to Figure 2.14
MG11BC22
Design Guide
HVAC Drive has a cos φ of 1
4
3
2
25 37,5 50Hz
Full load
& speed
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