m
3
/h
Distribution Valve regulation Frequency converter control
% Hours Power Consumption Power Consumption
A
1
- B
1
kWh A
1
- C
1
kWh
350 5 438 42,5 18.615 42,5 18.615
300 15 1314 38,5 50.589 29,0 38.106
250 20 1752 35,0 61.320 18,5 32.412
200 20 1752 31,5 55.188 11,5 20.148
150 20 1752 28,0 49.056 6,5 11.388
100 20 1752 23,0 40.296 3,5 6.132
Σ 100 8760 275.064 26.801
2.7.5 Better Control
If a frequency converter is used for controlling the flow or pressure of a system, improved control is obtained.
A frequency converter can vary the speed of the fan or pump, thereby 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.
Simple control of process (Flow, Level or Pressure) utilizing the built in PID control.
2.7.6 Cos φ Compensation
Generally speaking, a frequency converter with a cos φ of 1 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.
VLT
®
AQUA Drive Design Guide 2 Introduction to VLT AQUA Drive
MG.20.N5.02 - VLT
®
is a registered Danfoss trademark
17
2