Description Of Operation - Danfoss VLT AQUA Drive FC 202 Design Manual

Product Overview
Flow Distribution
rate
2 2
% Duration
[m 3 /h]
350 5
300 15
250 20
200 20
150 20
100 20
Σ 10
0
Table 2.2 Result
1) Power reading at point A1
2) Power reading at point B1
3) Power reading at point C1
2.1.6 Improved Control
Using a frequency converter to control the flow or
pressure of a system improves control.
A frequency converter can vary the speed of the fan or
pump, obtaining variable control of flow and pressure.
Furthermore, a frequency converter can quickly adapt the
speed of the fan or pump to new flow or pressure
conditions in the system.
Obtain simple control of process (flow, level or pressure)
utilising the built-in PI control.
2.1.7 Star/Delta Starter or Soft Starter
When large 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 Illustration 2.8, a frequency converter does
not consume more than rated current.
18
Valve regulation
Power Consump- Power Consump-
tion
[h] [kW] [kWh] [kW]
438 1) 18.615
42.5 42.5
1314 38.5 50.589 29.0
1752 35.0 61.320 18.5
1752 31.5 55.188 11.5
1752 28.0 49.056
1752 2) 40.296
23.0 3.5
8760 – 275.064
Danfoss A/S © 09/2014 All rights reserved.
Design Guide
Frequency 800
converter
700
control
600
tion
500
[kWh]
1) 18.615
400
38.106
300
32.412
20.148
200
6.5 11.388
100
3) 6.132
– 26.801
0
1 VLT ®
2 Star/delta starter
3 Soft starter
4 Start directly on mains
Illustration 2.8 Start-up Current

2.2 Description of Operation

The frequency converter supplies a regulated amount of
mains AC power to the motor to control its speed. The
frequency converter supplies variable frequency and
voltage to the motor.
The frequency converter is divided into 4 main modules:
•
•
•
•
Illustration 2.9 is a block diagram of the internal
components of the frequency converter. See Table 2.3 for
their functions.
Illustration 2.9 Frequency Converter Block Diagram
3
2
1
0 12,5 25
AQUA Drive FC 202
Rectifier
Intermediate DC bus circuit
Inverter
Control and regulation
4
37,5 50Hz
Full load
& speed
MG20N602