Danfoss VLT HVAC Design Manual page 41

®
VLT HVAC Drive Design Guide
2.9.3 EMC Test Results (Emission)
The following test results have been obtained using a system with a frequency converter (with options if relevant), a screened control cable, a
control box with potentiometer, as well as a motor and motor screened cable.
RFI filter type
Standard
H1
1.1-45 kW 200-240 V
1.1-90 kW 380-480 V
H2
1.1-3.7 kW 200-240 V
5.5-45 kW 200-240 V
1.1-7.5 kW 380-480 V
11-90 kW 380-480 V
110-1000 kW 380-480 V
45-1400 kW 525-690 V
H3
1.1-45 kW 200-240 V
1.1-90 kW 380-480 V
H4
110-1000 kW 380-480 V
45-400 kW 525-690 V
Hx
1.1-90 kW 525-600 V
Table 2.1: EMC Test Results (Emission)
HX, H1, H2 or H3 is defined in the type code pos. 16 - 17 for EMC filters
HX - No EMC filters build in the frequency converter (600 V units only)
H1 - Integrated EMC filter. Fulfil Class A1/B
H2 - No additional EMC filter. Fulfil Class A2
H3 - Integrated EMC filter. Fulfil class A1/B (Frame size A1 only)
H4 - Integrated EMC filter. Fulfil class A1
2.9.4 General Aspects of Harmonics Emission
A frequency converter takes up a non-sinusoidal current from mains,
which increases the input current I
RMS
formed by means of a Fourier analysis and split up into sine-wave
currents with different frequencies, i.e. different harmonic currents I
with 50 Hz as the basic frequency:
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 cur-
rents at a low level to avoid overload of the transformer and high
temperature in the cables.
NB!
Some of the harmonic currents might disturb communication equipment connected to the same transformer or cause resonance in
connection with power-factor correction batteries.
To ensure low harmonic currents, the frequency converter is equipped with intermediate circuit coils as standard. This normally reduces the input current
I by 40%.
RMS
Conducted emission.
Maximum shielded cable length.
Industrial environment
EN 55011 Class EN 55011
A2 Class A1
T2 150 m
T4 150 m
T2 5 m
T2 25 m
T4 5 m
T4 25 m
T4 150 m
T7 150 m
T2 75 m
T4 75 m
T4 150 m
T7 150 m
T6 -
. A non-sinusoidal current is trans-
N
MG.11.B9.02 - VLT ® is a registered Danfoss trademark
2 Introduction to VLT HVAC Drive
Housing, trades Industrial environ-
and light indus-
tries
EN 55011 Class B EN 55011 Class A1
150 m 50 m
150 m 50 m
No No
No No
No No
No No
No No
No No
50 m 10 m
50 m 10 m
150 m No
30 m No
- -
Harmonic currents
Hz
Radiated emission
Housing, trades and
ment light industries
EN 55011 Class B
Yes No
Yes No
No No
No No
No No
No No
No No
No No
Yes No
Yes No
Yes No
No No
- -
I I I
1 5 7
50 Hz 250 Hz 350 Hz
2
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