Danfoss vlt aqua - Page 12

1.1.6 Power Factor
The power factor is the relation between I
1
and I
RMS
.
Power factor =
3 × U × I
1 × COS ϕ
3 × U × I
RMS
The power factor for 3-phase control:
=
I
1
×
cos ϕ1
I
RMS
=
I
1
I
RMS
since cos ϕ1=1
The power factor indicates to which extent the adjustable frequency drive
imposes a load on the line power supply.
The lower the power factor, the higher the I
RMS
for the same kW per-
formance.
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 built-in DC coils in the adjustable frequency drive produce a high power factor, which minimizes the imposed load on the line power supply.
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®
AQUA Drive Design Guide
1-8 MG.20.N5.22 - VLT
®
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