Operating instructions

13
Harmonic distortion on the supply
grid is an increasing problem mainly
caused by electronic power devices
including frequency converters,
drawing non-sinusoidal current from
the mains supply. This creates
harmonic distortion on the supply
depending on the supply impedance.
Danfoss’ Harmonic Calculation
Software MCT 31 makes it possible to
calculate the extent of these
harmonics at the planning stage and
can suggest mitigation
countermeasures.
Harmonic mitigation can be particu-
larly valuable when the power supply
is backed up with emergency genera-
tors, which have poorer tolerance to
non-sinusoidal currents.
Current standards (EN 50106) are
included in the software analysis
tool which can quickly and easily
be downloaded from
www.drives.danfoss.com.
Data can be entered, stored and
recalled project by project. At a click
Keeps EMC on the safe side
Keeps your power supply clean
Optimum EMC protection coupled
with integrated harmonic fi lters
ensures that the optimum EMC
environment and cleanest power
supplies are maintained throughout
the operational lifetime of the
system, negating any reduction in
lifecycle costs.
VLT® HVAC Drive meets the EMC
product standard EN 61800-3 without
additional external components even
when using long motor cables, and
corresponds to the EMC guidelines
2004/108/EC, off ering performance
superior to other drives.
Critical for practical use is compliance
with the environment standard
EN 61800-3, class C1 (residential) and
Class C2 (industrial area).
C2 ensures reliable plant operation
through full compliance with all EMC
requirements, product standards,
prescribed warnings, and restrictions.
Integrated chokes minimise the
network eff ects drama tically and thus
maintain operation within the limits
of EN 61000-3-12.
These chokes also make the VLT®
HVAC Drive stable and highly
dynamic even during short supply
voltage drops or other poor network
conditions.
Categories according
to EN 61800-3
C1 C2 C3 C4
Limits according to EN 55011 Class B Class A1 Class A2
Exceeding
class A2
Comparison of limits EN 55011/61800-3
Clean power supply
VLT® HVAC Drive introduces a
minimum of RFI or harmonic
pollution into the building and
avoids problematic and, in some
countries/regions, performance
outside of their regulations.
VLT® HVAC Drive is a reliable and
cost eff ective investment.
DC coils reduce harmonic noise and protect
the drive. Also EMC fi lters are integrated
(meets EN 55011 A2, A1 or B).
Without fi lter
With AHF
With AHF
Harmonic disturbance with and without AHF fi lter.
Typical without fi lter
the software presents a clear
overview of each project with data
presented in both tabular and
bar-chart formats.