Danfoss VLT Flow Drive FC 111 Design Manual page 18

VLT® Flow Drive FC 111
Design Guide
350 5 438
300 15 1314
250 20 1752
200 20 1752
150 20 1752
100 20 1752
Σ 100 8760
3.1.1.5 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. Furthermore, a drive can quickly
adapt the speed of the fan or pump to new flow or pressure conditions in the system.
Simple control of process (flow, level, or pressure) utilizing the built-in PI control.
3.1.1.6 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 tradi-
tional systems, a star/delta starter or soft starter is widely used. Such motor starters are not required if a drive is used.
As shown in the following illustration, a drive does not consume more than rated current.
800
700
600
500
400
300
200
100
0
0 12,5
Illustration 8: Start-up Current
1 VLT® Flow Drive FC 111
2 Star/delta starter
3.1.1.7 Using a Drive Saves Money
The example in 3.1.1.8 Traditional Fan System without a Drive
ces other equipment. It is possible to calculate the cost of installing the 2 different systems. In the example, the 2 systems can be
established at roughly the same price.
Use the VLT® Energy Box software that is introduced in chapter Additional Resources to calculate the cost savings that can be ach-
ieved by using a drive.
18 | Danfoss A/S © 2021.04
42.5 18.615
38.5 50.589
35.0 61.320
31.5 55.188
28.0 49.056
23.0 40.296
– 275.064
4
3
2
1
25 37,5 50H z
F ull load
& speed
42.5
29.0
18.5
11.5
6.5
3.5
–
3 Soft starter
4 Start directly on mains
and 3.1.1.9 Fan System Controlled by Drives
Product Overview
18.615
38.106
32.412
20.148
11.388
6.132
26.801
shows that a drive repla-
AJ363928382091en-000101 / 130R0983