Danfoss VLT HVAC Basic Drive FC 101 Design Manual page 40

Product Overview
RFI Filter
2 2
Type
H3 RFI filter (Class A1/B)
20–60 hp
[15–45 kW]
3x200–
240 V IP20
40–125 hp
[30–90 kW]
3x380–
480 V IP20
1–25
[0.75–18.5
kW]
3x380–
480 V IP54
30–125 hp
[22–90 kW]
3x380–
480 V IP54
Table 2.12 Test Results
2.8.3 General Aspects of Harmonics Emission
An adjustable frequency drive takes up a non-sinusoidal current from the line power, which increases the input current I
A non-sinusoidal current is transformed by means of a Fourier analysis and split up into sine-wave currents with different
frequencies, i.e., different harmonic currents I
Hz
Table 2.13 Harmonic Currents
The harmonics do not affect the power consumption directly but increase the heat losses in the installation (transformer,
cables). Consequently, in plants with a high percentage of rectifier load, maintain harmonic currents at a low level to
prevent an overload of the transformer and high temperature in the cables.
Figure 2.24 Harmonic Currents
38
Conduct emission. Maximum shielded cable length [m]
Industrial environment
EN 55011 Class A2 EN 55011 Class A1
Without With Without
external external external
filter filter filter
50
50
25
25
Danfoss A/S © Rev. 2014-01-14 All rights reserved.
Design Guide
Housing, trades and
light industries
EN 55011 Class B
With Without With
external external external
filter filter filter
20
20
10
10
with 50 Hz as the basic frequency:
n
I
1
50
Radiated emission
Industrial Housing, trades and
environment light industries
EN 55011 Class A1 EN 55011 Class B
Without With Without
external external external
filter filter filter
Yes No
Yes No
Yes
Yes No
I I
5
250 350
With
external
filter
.
RMS
7
MG18C522