Danfoss VLT HVAC Drive FC 102 Design Manual page 31

Product Features
H
(mwg)
s
60
50
B
40
30
20
C
10
750rpm
0 100 200
P
(kW)
shaft
60
50
40
30
B 1
20
10
1050rpm
C 1
750rpm
0 100 200
Illustration 5.12 Energy Savings in a Pump Application
5.3.2 Using a Drive for Better Control
If a drive is used for controlling the flow or pressure of a
system, improved control is obtained. A drive can vary the
speed of the fan or pump, obtaining variable control of
flow and pressure utilizing the built-in PID control.
Furthermore, a drive can quickly adapt the speed of the
fan or pump to new flow or pressure conditions in the
system.
Cos φ compensation
®
HVAC Drive has a cos φ of 1 and
Typically, the VLT
provides power factor correction for the cos φ of the
motor, which means there is no need to make allowance
for the cos φ of the motor when sizing the power factor
correction unit.
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 drive is used. As illustrated in Illustration 5.13, a drive
does not consume more than rated current.
MG16C302
Design Guide
A
1650rpm
1350rpm
1050rpm
( 3 )
m /h
300 400
A 1
1650rpm
1350rpm
( )
300 400 m 3 /h
Danfoss A/S © 11/2017 All rights reserved.
800
700
600
500
400
300
200
100
1
0
0 12,5
1 ®
VLT HVAC Drive FC 102
2 Star/delta starter
3 Soft starter
4 Start directly on mains
Illustration 5.13 Current Consumption with a Drive
4
3
2
25 37,5 50Hz
Full load
& speed
29
5 5