Danfoss VLT AutomationDrive FC 300 Guide

MAKING MODERN LIVING POSSIBLE
OOutput Filters Design Guide
VLTpAutomationDrive FC 300
VLTpAQUA Drive FC 200
VLTpHVAC Drive FC 100
www.danfoss.com/drives
*MG90N502*
130R0457 MG90N502 Rev. 2010-10-19

Contents
1 How to Read this Design Guide 3
1.1.2 Abbreviations 3
2 Safety and Conformity 4
2.1 Safety Precautions 4
2.1.1 CE Conformity and Labelling 4
3 Introduction to Output Filters 5
3.1 Why use Output Filters 5
3.2 Protection of Motor Insulation 5
3.2.1 The Output Voltage 5
3.3 Reduction of Motor Acoustic Noise 7
3.4 Reduction of High Frequency Electromagnetic Noise in the Motor Cable 8
3.5 What are Bearing Currents and Shaft Voltages? 9
3.5.1 Mitigation of Premature Bearing Wear-Out 9
3.5.2 Measuring Electric Discharges in the Motor Bearings 10
3.6 Which Filter for which Purpose 12
3.6.1 dU/dt Filters 12
3.6.2 Sine-wave Filters 14
3.6.3 High-Frequency Common-Mode Core Kits 16
4 Selection of Output Filters 17
4.1 How to Select the Correct Output Filter 17
4.1.1 Product Overview 17
4.1.2 HF-CM Selection 19
4.2 Electrical Data - dU/dt Filters 20
4.3 Electrical Data - Sine-wave Filters 22
4.3.1 Spare Parts/Accessories 27
4.3.2 Cable Glands for Floor Standing Filters 27
4.3.3 Terminal Kits 28
4.4 Sine-Wave Filters 29
4.4.1 dU/dt Filters 30
4.4.2 Sine-Wave Foot Print Filter 31
5 How to Install 32
5.1 Mechanical Mounting 32
5.1.1 Safety Requirements for Mechanical Installation 32
5.1.2 Mounting 32
5.1.3 Mechanical Installation of HF-CM 32
5.1.4 Earthing of Sine-wave and dU/dt Filters 33
Contents Output Filters Design Guide
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5.1.5 Screening 33
5.2 Mechanical Dimensions 34
5.2.1 Sketches 34
6 How to Programme the Frequency Converter 43
6.1.1 Parameter Settings for Operation with Sine-wave Filter 43
Index 44
Contents Output Filters Design Guide
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1 How to Read this Design Guide
This Design Guide will introduce all aspects of output filters
for your frequency converter; from choosing the right output
filter for the application to instructions about how to install it
and how to program the frequency converter.
Danfoss technical literature is also available online at
www.danfoss.com/BusinessAreas/DrivesSolutions/Documen-
tations/Technical+Documentation.
1.1.1 Symbols
Symbols used in this manual
NOTE
Indicates something to be noted by the reader.
CAUTION
Indicates a general warning.
WARNING
Indicates a high-voltage warning.
✮Indicates default setting
1.1.2 Abbreviations
Alternating current AC
American wire gauge AWG
Ampere/AMP A
Automatic Motor Adaptation AMA
Current limit ILIM
Degrees Celsius °C
Direct current DC
Drive Dependent D-TYPE
Electro Magnetic Compatibility EMC
Electronic Thermal Relay ETR
Drive FC
Gram g
Hertz Hz
Kilohertz kHz
Local Control Panel LCP
Meter m
Millihenry Inductance mH
Milliampere mA
Millisecond ms
Minute min
Motion Control Tool MCT
Nanofarad nF
Newton Meters Nm
Nominal motor current IM,N
Nominal motor frequency fM,N
Nominal motor power PM,N
Nominal motor voltage UM,N
Parameter par.
Protective Extra Low Voltage PELV
Rated Inverter Output Current IINV
Revolutions Per Minute RPM
Second sec.
Synchronous Motor Speed ns
Torque limit TLIM
Volts V
IVLT,MAX The maximum output current.
IVLT,N The rated output current
supplied by the frequency
converter.
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2 Safety and Conformity
2.1 Safety Precautions
Equipment containing electrical components
may not be disposed of together with domestic
waste.
It must be separately collected with electrical
and electronic waste according to local and
currently valid legislation.
MCC 101/102
Design Guide
2.1.1 CE Conformity and Labelling
What is CE Conformity and Labelling?
The purpose of CE labelling is to avoid technical trade
obstacles within EFTA and the EU. The EU has introduced the
CE label as a simple way of showing whether a product
complies with the relevant EU directives. The CE label says
nothing about the specifications or quality of the product.
The low-voltage directive (73/23/EEC)
Frequency converters must be CE labelled in accordance
with the low-voltage directive of January 1, 1997. The
directive applies to all electrical equipment and appliances
used in the 50 - 1000V AC and the 75 - 1500V DC voltage
ranges. Danfoss CE-labels in accordance with the directive
and issues a declaration of conformity upon request.
Warnings
CAUTION
When in use the filter surface temperature rises. DO NOT
touch the filter during operation.
WARNING
Never work on a filter in operation. Touching the electrical
parts may be fatal - even after the equipment has been
disconnected from the frequency converter or motor.
WARNING
Before servicing the filter, wait at least the voltage discharge
time stated in the Design Guide for the corresponding
frequency converter to avoid electrical shock hazard.
NOTE
Never attempt to repair a defect filter.
NOTE
The filters presented in this design guide are specially
designed and tested for Danfoss frequency converters (FC
102/202/301 and 302). Danfoss takes no resposibility for the
use of third party output filters.
NOTE
The phased out LC-filters that were developed for the
VLT5000 series and are not compatible with the VLT FC
100/200/300.
However, the new filters are compatible with both FC-series
and VLT 5000-series
NOTE
690V applications:
For motors not specially designed for frequency converter
operation or without double insulation, Danfoss highly
recommend the use of either dU/dt or Sine-Wave filters.
NOTE
Sine-wave filters can be used at switching frequencies higher
than the nominal switching frequency, but should never be
used at switching frequencies with less than 20% lower than
the nominal switching frequency.
NOTE
dU/dt filters, unlike Sine-wave filters, can be used at lower
switching frequency than the nominal switching frequency,
but higher switching frequency will cause overheating of the
filter and should be avoided.
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3 Introduction to Output Filters
3.1 Why use Output Filters
This chapter describes why and when to use Output Filters
with Danfoss frequency converters. It is divided into 4
sections:
•Protection of Motor Insulation
•Reduction of Motor Acoustic Noise
•Reduction of High Frequency Electromagnetic
Noise in Motor Cable
•Bearing currents and shaft voltage
3.2 Protection of Motor Insulation
3.2.1 The Output Voltage
The output voltage of the frequency converter is a series of
trapezoidal pulses with a variable width (pulse width
modulation) characterized by a pulse rise-time tr.
When atransistor in the inverter switches, the voltage across
the motor terminal increases by a dU/dt ratio that depends
on:
•the motor cable (type, cross-section, length,
screened or unscreened, inductance and
capacitance)
•the high frequency surge impendance of the motor
Because of the impedance mismatch between the cable
characteristic impedance and the motor surge impedance a
wave reflection occurs, causing a ringing voltage overshoot
at the motor terminals - see Illustration 3.1. The motor surge
impedance decreases with the increase of motor size
resulting in reduced mismatch with the cable impedance.
The lower reflection coefficient (Γ) reduces the wave
reflection and thereby the voltage overshoot. Typical values
are given in Table 3.1.
In the case of parallel cables the cable characteristic
impedance is reduced, resulting in a higher reflection
coefficient higher overshoot. For more information please
see IEC 61800-8.
Illustration 3.1 Example of Converter Output Voltage (dotted line) and Motor Terminal Voltage After 200m of Cable (solid line)
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Typical values for the rise time and peak voltage UPEAK are
measured on the motor terminals between two phases.
Two different definitions for the risetime trare used in
practice. The international IEC standards define the rise-time
as the time between 10% to 90% of the peak voltage Upeak.
The US National Electrical Manufacturers Association (NEMA)
defines the rise-time as the time between 10% and 90% of
the final, settled voltage, that is equal to the DC link voltage
UDC. See Illustration 3.2 and Illustration 3.3.
To obtain approximate values for cable lengths and voltages
not mentioned below, use the following rules of thumb:
1. Rise time increases with cable length.
2. UPEAK = DC link voltage x (1+Γ); Γrepresents the
reflection coefficient and typical values can be
found in table below
(DC link voltage = Mains voltage x 1.35).
3. dU/dt =
0.8 × UPEAK
tr
(IEC)
dU/dt =
0.8 × U
DC
tr ( NEMA )(NEMA)
(For dU/dt, rise time, Upeak values at different cable lengths
please consult the drive Design Guide)
Motor power [kW] Zm [Ω]Γ
<3.7 2000 - 5000 0.95
90 800 0.82
355 400 0.6
Table 3.1 Typical Values for Reflection Coefficients (IEC 61800-8).
The IEC and NEMA Definitions of Risetime tr
Illustration 3.2 IEC
Illustration 3.3 NEMA
Various standards and technical specifications present limits
of the admissible Upeak and trfor different motor types. Some
of the most used limit lines are shown in Illustration 3.4
•IEC 60034-17 – limit line for general purpose
motors when fed by frequency converters, 500V
motors.
•IEC 60034-25 – limit for converter rated motors:
curve A is for 500V motors and curve B is for 690V
motors.
•NEMA MG1 –Definite purpose Inverter Fed Motors.
If, in your application, the resulting Upeak and trexceed the
limits that apply for the motor used, an output filter should
be used for protecting the motor insulation.
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Illustration 3.4 Limit Lines for Upeak and Risetime tr.
3.3 Reduction of Motor Acoustic Noise
The acoustic noise generated by motors has three main
sources.
1. The magnetic noise produced by the motor core,
through magnetostriction
2. The noise produced by the motor bearings
3. The noise produced by the motor ventilation
When a motor is fed by a frequency converter, the
pulsewidth modulated (PWM) voltage applied to the motor
causes additional magnetic noise at the switching frequency
and harmonics of the switching frequency (mainly the
double of the switching frequency). In some applications this
is not acceptable. In order to eliminate this additional
switching noise, a sine-wave filter should be used. This will
filter the pulse shaped voltage from the frequency converter
and provide a sinusoidal phase-to-phase voltage at the
motor terminals.
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3.4 Reduction of High Frequency Electromagnetic Noise in the Motor Cable
When no filters are used, the ringing voltage overshoot that occurs at the motor terminals is the main high-frequency noise
source. Illustration 3.5 shows the correlation between the frequency of the voltage ringing at the motor terminals and the
spectrum of the high-frequency conducted interference in the motor cable.
Besides this noise component, there are also other noise components such as:
•The common-mode voltage between phases and ground at the switching frequency and its harmonics - high
amplitude but low frequency.
•High-frequency noise (above 10MHz) caused by the switching of semiconductors -high frequency but low amplitude.
Illustration 3.5 Correlation Between the Frequency of the Ringing Voltage Overshoot and the Spectrum of Noise Emissions.
When an output filter is installed following effect is achieved:
•In the case of dU/dt filters the frequency of the ringing oscillation is reduced below 150kHz.
•In the case of sine-wave filters the ringing oscillation is completely eliminated and the motor is fed by a sinusoidal
phase-to-phase voltage.
Remember, that the other two noise components are still present. This is illustrated in the conducted emission measurements
shown in Illustration 3.7 and Illustration 3.8. The use of unshielded motor cables is possible, but the layout of the installation
should prevent noise coupling between the unshielded motor cable and the mains line or other sensitive cables (sensors,
communication, etc.). This can be achieved by cable segregation and placement of the motor cable in a separate, continuous
and grounded cable tray.
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3.5 What are Bearing Currents and Shaft
Voltages?
Fast switching transistors in the frequency converter
combined with an inherent common-mode voltage (voltage
between phases and ground) generate high-frequency
bearing currents and shaft voltages. While bearing currents
and shaft voltages can also occur in direct-on-line motors,
these phenomena are accentuated when the motor is fed
from a frequency converter. The majority of bearing
damages in motors fed by frequency converters are because
of vibrations, misalignment, excessive axial or radial loading,
improper lubrication, impurities in the grease. In some cases,
bearing damages are caused by bearing currents and shaft
voltages. The mechanism that causes bearing currents and
shaft voltages is quite intricate and beyond the scope of this
Design Guide. Basically, two main mechanisms can be
identified:
•Capacitive coupling: the voltage across the bearing
is generated by parasitic capacitances in the motor.
•Inductive coupling: caused by circulating currents
in the motor.
The grease film of a running bearing behaves like isolation.
The voltage across the bearing can cause abreakdown of the
grease film and produce a small electric discharge (a spark)
between the bearing balls and the running track. This
discharge produces amicroscopic melting of the bearing ball
and running track metal and in time it causes the premature
wear-out of the bearing. This mechanism is called Electrical
Discharge Machining or EDM.
3.5.1 Mitigation of Premature Bearing Wear-
Out
There are a number of measures that can be taken for
preventing premature wearing and damage of the bearings
(not all of them are applicable in all cases – combinations
can be used). These measures aim either to provide a low-
impedance return path to the high-frequency currents or to
electrically isolate the motor shaft for preventing currents
through the bearings. Besides, there are also mechanical
related measures.
Measures to provide a low-impedance return path
•Follow EMC installation rules strictly. A good high-
frequency return path should be provided between
motor and frequency converter, for example by
using shielded cables.
•Make sure that the motor is properly grounded and
the grounding has a low-impedance for high-
frequency currents.
•Provide agood high-frequency ground connection
between motor chassis and load.
•Use shaft grounding brushes.
Measures that isolate the motor shaft from the load
•Use isolated bearings (or at least one isolated
bearing at the non-driving end NDE).
•Prevent shaft ground current by using isolated
couplings.
Mechanical measures
•Make sure that the motor and load are properly
aligned.
•Make sure the loading of the bearing (axial and
radial) is within the specifications.
•Check the vibration level in the bearing.
•Check the grease in the bearing and make sure the
bearing is correctly lubricated for the given
operating conditions.
One of the mitigation measures is to use filters. This can be
used in combination with other measures, such as those
presented above. High-frequency common-mode (HF-CM)
filters (core kits) are specially designed for reducing bearing
stress. Sine-wave filters also have a good effect. dU/dt filters
have less effect and it is recommended to use them in
combination with HF-CM cores.
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3.5.2 Measuring Electric Discharges in the
Motor Bearings
The occurrence of electric discharges in the motor bearings
can be measured using an oscilloscope and a brush to pick
up the shaft voltage. This method is difficult and the
interpretation of the measured waveforms requires a deep
understanding of the bearing current phenomena. An easy
alternative is to use an electrical discharge detector
(130B8000), as shown in Illustration 3.6. Such a device
consists of a loop antenna that receives signals in the
frequency range of 50MHz – 200MHz and a counter. Each
electric discharge produces an electromagnetic wave that is
detected by the instrument and the counter is incremented.
If the counter displays ahigh number of discharges it means
that there are many discharges occurring in the bearing and
mitigation measures have to be taken to prevent the early
wear out of the bearing. This instrument can be used for
experimentally determining the exact number of cores
needed to reduce bearing currents. Start with a set of 2
cores. If the discharges are not eliminated, or drastically
reduced, add more cores. The number of cores presented in
the table above is a guiding value that should cover most
applications with a generous safety margin. If the cores are
installed on the drive terminals and you experiment core
saturation because of long motor cables (the cores have no
effect on bearing currents), check the correctness of the
installation. If cores keep saturating after the installation is
made according to EMC best practice, consider moving the
cores to the motor terminals.
129
50 - 200
MHz
130BB729.10
130B8000
Illustration 3.6 Electrical Discharge Detector
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Level in dBµV
Frequency in Hz
130BT119.10
Illustration 3.7 Mains Line Conducted Noise, No Filter
Illustration 3.8 Mains Line Conducted Noise, Sine-wave Filter
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3.6 Which Filter for which Purpose
Table 3.2 shows acomparison of dU/dt, Sine-wave filter, and HF-CMperformance. It can be used to determine which filter to use
with your application.
Performance criteria dU/dt filters Sine-wave filters High-frequency common-mode filters
Motor insulation
stress
Up to 150m cable (screened/
unscreened) complies with the
requirements of IEC 60034-171
(general purpose motors). Above
this cable length the risk of “double
pulsing” (two time mains network
voltage) increases.
Provides a sinusoidal phase-to-phase
motor terminal voltage. Complies with
IEC 60034-17 1and NEMA-MG1
requirements for general purpose
motors with cables up to 500m (1km for
VLT frame size D and above).
Does not reduce motor insulation stress
Motor bearing stress Slightly reduced, only in high-
power motors.
Reduces bearing currents caused by
circulating currents. Does not reduce
common-mode currents (shaft
currents).
Reduces bearing stress by limiting
common-mode high-frequency
currents
EMC performance Eliminates motor cable ringing.
Does not change the emission class.
Does not allow longer motor cables
as specified for the frequency
converter’s built-in RFI filter.
Eliminates motor cable ringing. Does
not change the emission class. Does not
allow longer motor cables as specified
for the frequency converter’s built-in
RFI filter.
Reduces high-frequency emissions
(above 1MHz). Does not change the
emission class of the RFI filter. Does not
allow longer motor cables as specified
for the frequency converter.
Max. motor cable
length
100m ... 150m
With guaranteed EMC performance:
150m screened.
Without guaranteed EMC
performance: 150m unscreened.
With guaranteed EMC performance:
150m screened and 300m unscreened.
Without guaranteed EMC performance:
up to 500m (1km for VLT frame size D
and above)
150m screened (frame size A, B, C), 300
m screened (frame size D, E, F), 300 m
unscreened
Acoustic motor
switching noise
Does not eliminate acoustic
switching noise.
Eliminates acoustic switching noise
from the motor caused by magneto-
striction.
Does not eliminate acoustic switching
noise.
Relative size 15-50% (depending on power size) 100% 5 - 15%
Voltage drop 0.5% 4-10% none
Table 3.2 Comparison of dU/dt and Sine-wave Filters
1) Not 690V.
2) See general specification for formula.
3.6.1 dU/dt Filters
The dU/dt filters consist of inductors and capacitors in alow
pass filter arrangement and their cut off frequency is above
the nominal switching frequency of the frequency converter.
The inductance (L) and capacitance (C) values are shown in
the tables in 4.2 Electrical Data - dU/dt Filters. Compared to
Sine-wave filters they have lower L and C values, thus they
are cheaper and smaller. With adU/dt filter the voltage wave
form is still pulse shaped but the current is sinusoidal - see
following illustrations.
Features and benefits
dU/dt filters reduce the voltage peaks and dU/dt of the
pulses at the motor terminals. The dU/dt filters reduce dU/dt
to approx. 500V/μs.
Advantages
•Protects the motor against high dU/dt values and
voltage peaks, hence prolongs the lifetime of the
motor
•Allows the use of motors which are not specifically
designed for converter operation, for example in
retrofit applications
Application areas
Danfoss recommends the use of dU/dt filters in the following
applications:
•Applications with frequent regenerative braking
•Motors that are not rated for frequency converter
operation and not complying with IEC 600034-25
•Motors placed in aggressive environments or
running at high temperatures
•Applications with risk of flash over
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•Installations using old motors (retrofit) or general
purpose motors not complying with IEC 600034-17
•Applications with short motor cables (less than
15m)
•690V applications
Voltage and current with and without dU/dt filter:
Illustration 3.9 Without Filter
Illustration 3.10 With dU/dt Filter
130BB113.11
Upeak [kV]
15m dv/dt filter
rise time [µs]
150m dv/dt filter
50m dv/dt filter
Illustration 3.11 Measured dU/dt values (rise time and peak
voltages) with and without dU/dt filter using 15m, 50m and 150m
cable lengths on a 400V, 37kW induction motor.
The dU/dt value decreases with the motor cable length
whereas the peak voltage increases (see Illustration 3.11). The
Upeak value depends on the Udc from the frequency converter
and as Udc increases during motor braking (generative) Upeak
can increase to values above the limits of IEC 60034-17 and
thereby stress the motor insulation. Danfoss therefore
recommends dU/dt filters in applications with frequent
braking. Furthermore the illustration above shows how the
Upeak increases with the cable length. As the cable length
increases, the cable capacitance rises and the cable behaves
like alow-pass filter. That means longer rise-time trfor longer
cables. Therefore it is recommended to use dU/dt filters only
in applications with cable lengths up to 150m. Above 150m
dU/dt filters have no effect. If further reduction is needed,
use a sine-wave filter.
Filter features
•IP00 and IP20/23/54 enclosure in the entire power
range
•Side by side mounting with the drive
•Reduced size, weight and price compared to the
sine-wave filters
•Possibility of connecting screened cables with
included decoupling plate
•Compatible with all control principles including
flux and VVCPLUS
•Filters wall mounted up to 177A and floor mounted
above that size
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Illustration 3.12 525V - With and Without dU/dt Filter
Illustration 3.13 690V - With and Without dU/dt Filter
Source: Test of 690V 30kW VLT FC 302 with MCC 102 dU/dt
filter
Illustration 3.12 and Illustration 3.13 show how Upeak and rise
time behaves as a function of the motor cable length. In
installations with short motor cables (below 5-10m) the rise
time is short which causes high dU/dt values. The high dU/dt
can cause adamaging high potential difference between the
windings in the motor which can lead to breakdown of the
insulation and flash-over. Danfoss therefore recommends
dU/dt filters in applications with motor cable lengths shorter
than 15m.
3.6.2 Sine-wave Filters
Sine-wave filters are designed to let only low frequencies
pass. High frequencies are consequently shunted away
which results in a sinusoidal phase to phase voltage
waveform and sinusoidal current waveforms. With the
sinusoidal waveforms the use of special frequency converter
motors with reinforced insulation is no longer needed. The
acoustic noise from the motor is also damped as a
consequence of the sinusoidal wave condition. The sine-
wave filter also reduces insulation stress and bearing
currents in the motor, thus leading to prolonged motor
lifetime and longer periods between services. Sine-wave
filters enable use of longer motor cables in applications
where the motor is installed far from the frequency
converter. As the filter does not act between motor phases
and ground, it does not reduce leakage currents in the
cables. Therefore the motor cable length is limited - see
Table 3.2.
The Danfoss Sine-wave filters are designed to operate with
the VLT®FC 100/200/300. They replace the LC-filter product
range and are backwards compatible with the VLT
5000-8000 Series Drives. They consist of inductors and
capacitors in a low-pass filter arrangement. The inductance
(L) and capacitance (C) values are shown in tables in
4.3 Electrical Data - Sine-wave Filters.
Features and benefits
As described above, Sine-wave filters reduce motor
insulation stress and eliminate switching acoustic noise from
the motor. The motor losses are reduced because the motor
is fed with a sinusoidal voltage, as shown in Illustration 3.12.
Moreover, the filter eliminates the pulse reflections in the
motor cable thus reducing the losses in the frequency
converter.
Advantages
•Protects the motor against voltage peaks hence
prolongs the lifetime
•Reduces the losses in the motor
•Eliminates acoustic switching noise from the motor
•Reduces semiconductor losses in the drive with
long motor cables
•Decreases electromagnetic emissions from motor
cables by eliminating high frequency ringing in the
cable
•Reduces electromagnetic interference from
unscreened motor cables
•Reduces the bearing current thus prolonging the
lifetime of the motor
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Voltage and current with and without Sine-wave filter
Illustration 3.14 Without Filter
Illustration 3.15 With Sine-wave Filter
Application areas
Danfoss recommends the use of Sine-wave filters in the
following applications.
•Applications where the acoustic switching noise
from the motor has to be eliminated
•Retrofit installations with old motors with poor
insulation
•Applications with frequent regenerative braking
and motors that do not comply with IEC 60034-17
•Applications where the motor is placed in
aggressive environments or running at high
temperatures
•Applications with motor cables above 150m up to
300m (with both screened and unscreened cable).
The use of motor cables longer than 300m
depends on the specific application
•Applications where the service interval on the
motor has to be increased
•690V applications with general purpose motors
•Step up applications or other applications where
the frequency converter feeds a transformer
Example of relative motor sound pressure level
measurements with and without Sine-wave filter
Features
•IP00 and IP20 enclosure in the entire power range
(IP23 for floor standing filters)
•Compatible with all control principle including flux
and VVCPLUS
•Side by side mount with the frequency converter
up to 75A
•Filter enclosure matching the frequency converter
enclosure
•Possibility of connecting unscreened and screened
cables with included decoupling plate
•Filters wall mounted up to 75A and floor mount
above
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•Parallel filter installation is possible with
applications in the high power range
3.6.3 High-Frequency Common-Mode Core
Kits
High-frequency common-mode (HF-CM) core kits are one of
the mitigation measures to reduce bearing wear. However,
they should not be used as the sole mitigation measure.
Even when HF-CM cores are used, the EMC-correct instal-
lation rules must be followed. The HF-CM cores work by
reducing the high-frequency common-mode currents that
are associated with the electric discharges in the bearing.
They also reduce the high-frequency emissions from the
motor cable which can be used, for example, in applications
with unshielded motor cables.
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4 Selection of Output Filters
4.1 How to Select the Correct Output Filter
An output filter is selected based on the nominal motor current. All filters are rated for 160% overload for 1 minute, every 10
minutes.
4.1.1 Product Overview
To simplify the Filter Selection Table 4.1 shows which Sine-wave filter to use with aspecific frequency converter. This is based on
the 160% overload for 1 minute every 10 minutes and is to be considered guideline.
Mains supply 3 x 240 to 500V
Rated filter
current at 50Hz
Minimum
switching
frequency [kHz]
Maximum output
frequency [Hz] With
derating
Code number
IP20
Code number
IP00
Frequency converter size
200-240V 380-440V 441-500V
2.5 5 120 130B2439 130B2404 PK25 - PK37 PK37 - PK75 PK37 - PK75
4.5 5 120 130B2441 130B2406 PK55 P1K1 - P1K5 P1K1 - P1K5
8 5 120 130B2443 130B2408 PK75 - P1K5 P2K2 - P3K0 P2K2 - P3K0
10 5 120 130B2444 130B2409 P4K0 P4K0
17 5 120 130B2446 130B2411 P2K2 - P4K0 P5K5 - P7K5 P5K5 - P7K5
24 4 100 130B2447 130B2412 P5K5 P11K P11K
38 4 100 130B2448 130B2413 P7K5 P15K - P18K P15K - P18K
48 4 100 130B2307 130B2281 P11K P22K P22K
62 3 100 130B2308 130B2282 P15K P30K P30K
75 3 100 130B2309 130B2283 P18K P37K P37K
115 3 100 130B3181 130B3179 P22K - P30K P45K - P55K P55K - P75K
180 3 100 130B3183 130B3182 P37K - P45K P75K - P90K P90K - P110
260 3 100 130B3185 130B3184 P110 - P132 P132
410 3 100 130B3187 130B3186 P160 - P200 P160 - P200
510 3 100 130B3189 130B3188 P250 P250
660 2 70 130B3192 130B3191 P315 - P355 P315 - P355
800 2 70 130B3194 130B3193 P400 P400 - P450
1020 2 70 2 x 130B3189 2 x 130B3188 P450 - P500 P500 - P560
1320 2 70 2 x 130B3192 2 x 130B3191 P560 - P630 P630 - P710
1530 2 70 3 x 130B3189 3 x 130B3188 P710 - P800 P800
1980 2 70 3 x 130B9192 3 x 130B3191 P1M0
Table 4.1 Filter Selection
Selection of Output Filters Output Filters Design Guide
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Mains supply 3 x 525 to 600/690V
Rated filter
current at 50Hz
Minimum
switching
frequency [kHz]
Maximum output
frequency [Hz] With
derating
Code number
IP20
Code number
IP00
Frequency converter size
525-600V 525-690V
13 2 70 130B3196 130B3195 PK75 - P7K5
28 2 100 130B4113 130B4112 P11K - P18K
45 2 100 130B4115 130B4114 P22K - P30K P37K
76 2 100 130B4117 130B4116 P37K - P45K P45K - P55K
115 2 100 130B4119 130B4118 P55K - P75K P75K - P90K
165 2 70 130B4124 130B4121 P110 - P132
260 2 100 130B4126 130B4125 P160 - P200
303 2 70 130B4151 130B4129 P250
430 1.5 60 130B4153 130B4152 P315 - P400
530 1.5 100 130B4155 130B4154 P500
660 1.5 100 130B4157 130B4156 P560 - P630
868 1.5 60 2 x 130B4153 2 x 130B4152 P710
1060 1.5 100 2 x 130B4155 2 x 130B4154 P800 - P900
1590 1.5 60 3 x 130B4155 3 x 130B4154 P1M0
Table 4.2 Filter Selection
Generally the output filters are designed for the nominal
switching frequency of the frequency converter.
NOTE
Sine-wave filters can be used at switching frequencies higher
than the nominal switching frequency, but should never be
used at switching frequencies with less than 20% lower than
the nominal switching frequency.
NOTE
dU/dt filters, unlike Sine-wave filters, can be used at lower
switching frequency than the nominal switching frequency,
but higher switching frequency will cause the overheating of
the filter and should be avoided.
Selection of Output Filters Output Filters Design Guide
18 MG.90.N5.02 - VLT®is a registered Danfoss trademark
44

4.1.2 HF-CM Selection
The cores can be installed at the frequency converter’s
output terminals (U, V, W) or in the motor terminal box.
When installed at the frequency converter’s terminals the
HF-CM kit reduces both bearing stress and high-frequency
electromagnetic interference from the motor cable. The
number of cores depends on the motor cable length and
frequency converter voltage and a selection table is shown
below.
Cable
length
[m]
A- and B
frame
C frame D frame E- F frame
T5 T7 T5 T7 T5 T7 T5 T7
50 2 4 2 2 2 4 2 2
100 4 4 2 4 4 4 2 4
150 4 6 4 4 4 4 4 4
300 4 6 4 4 4 6 4 4
When installed in the motor terminal box the HF-CM kit
reduces only bearing stress and has no effect on the electro-
magnetic interference from the motor cable. Two cores are
sufficient in most cases, independent of the motor cable
length.
Danfoss provides the HF-CM cores in kits of two pieces/kit.
The cores are oval shaped for the ease of installation and are
available in four sizes: for Aand Bframes, for Cframes, for D
frames, for Eand Fframes. For Fframe frequency converters,
one core kit shall be installed at each inverter module
terminals. Mechanical mounting can be made with cable ties.
There are no special requirements regarding mechanical
mounting.
W
w
Hh
d
130BB728.10
In normal operation the temperature is below 70°C.
However, if the cores are saturated they can get hot, with
temperatures above 70°C. Therefore it is important to use
the correct number of cores to avoid saturation. Saturation
can occur if the motor cable is too long, motor cables are
paralleled or high capacitance motor cables, not suitable for
frequency converter operation, are used. Always avoid motor
cables with sector-shaped cores. Use only cables with round-
shaped cores.
CAUTION
Check the core temperature during commissioning. A
temperature above 70°C indicates saturation of the cores. If
this happens add more cores. If the cores still saturate it
means that the cable capacitance is too large because of: too
long cable, too many parallel cables, cable type with high
capacitance.
Applications with parallel cables
When parallel cables are used the total cable length has to
be considered. For example 2 x 100m cables are equivalent
with one 200m cable. If many paralleled motors are used a
separate core kit should be installed for each individual
motor.
The ordering numbers for the core kits (2 cores/package) are
given in the following table.
VLT
frame
size
Danfoss
part no.
Core dimension [mm] Weight Packaging
dimension
W w H h d [kg] [mm]
A and B 130B3257 60 43 40 25 22 0.25 130x100x70
C 130B3258 102 69 61 28 37 1.6 190x100x70
D 130B3259 189 143 126 80 37 2.45 235x190x
140
E and F 130B3260 305 249 147 95 37 4.55 290x260x
110
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