Power Factor - Danfoss VLT HVAC Basic Drive FC 101 Design Manual

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1 1
activating reset or, in some cases, by being programmed
to reset automatically. Trip locked may not be used for
personal safety.
VT Characteristics
Variable torque characteristics used for pumps and fans.
plus
VVC
If compared with standard voltage/frequency ratio control,
Voltage Vector Control (VVC
and the stability, both when the speed reference is
changed and in relation to the load torque.

1.1.6 Power Factor

The power factor is the relation between I
3 ×
Power factor =
The power factor for 3-phase control:
I 1 × cos ϕ1
= =
I RMS
The power factor indicates to which extent the frequency
converter imposes a load on the mains supply.
The lower the power factor, the higher the I
same kW performance.
I RMS = I 1 2 + I 5 2 + I 7 2 + . . + I n 2
In addition, a high power factor indicates that the different
harmonic currents are low.
The frequency converters built-in DC coils produce a high
power factor, which minimizes the imposed load on the
mains supply.
8
plus ) improves the dynamics
and I
1
U × I 1 × COS ϕ
U × I RMS
3 ×
I 1
since cos ϕ1 = 1
I RMS
MG18C402 - VLT
®
VLT HVAC Basic Drive Design Guide
.
RMS
for the
RMS
®
is a registered Danfoss trademark