Danfoss VLT HVAC Basic Drive FC 101 Guide

MAKING MODERN LIVING POSSIBLE
Design Guide
VLT®HVAC Basic Drive FC 101
vlt-drives.danfoss.com

Contents
1 Introduction 6
1.1 Purpose of the Design Guide 6
1.2 Document and Software Version 6
1.3 Safety Symbols 6
1.4 Abbreviations 6
1.5 Additional Resources 7
1.6 Denitions 7
1.7 Power Factor 9
1.8 Regulatory Compliance 9
1.8.1 CE Mark 9
1.8.2 UL Compliance 10
1.8.3 RCM Mark Compliance 10
2 Safety 11
2.1 Qualied Personnel 11
2.2 Safety Precautions 11
3 Product Overview 13
3.1 Advantages 13
3.1.1 Why use a Frequency Converter for Controlling Fans and Pumps? 13
3.1.2 The Clear Advantage - Energy Savings 13
3.1.3 Example of Energy Savings 13
3.1.4 Comparison of Energy Savings 14
3.1.5 Example with Varying Flow over 1 Year 15
3.1.6 Better Control 15
3.1.7 Star/Delta Starter or Soft Starter not Required 16
3.1.8 Using a Frequency Converter Saves Money 16
3.1.9 Without a Frequency Converter 17
3.1.10 With a Frequency Converter 18
3.1.11 Application Examples 19
3.1.12 Variable Air Volume 19
3.1.13 The VLT Solution 19
3.1.14 Constant Air Volume 20
3.1.15 The VLT Solution 20
3.1.16 Cooling Tower Fan 21
3.1.17 The VLT Solution 21
3.1.18 Condenser Pumps 22
3.1.19 The VLT Solution 22
3.1.20 Primary Pumps 23
3.1.21 The VLT Solution 23
Contents Design Guide
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3.1.22 Secondary Pumps 25
3.1.23 The VLT Solution 25
3.2 Control Structures 26
3.2.1 Control Structure Open Loop 26
3.2.2 PM/EC+ Motor Control 26
3.2.3 Local (Hand On) and Remote (Auto On) Control 26
3.2.4 Control Structure Closed Loop 27
3.2.5 Feedback Conversion 28
3.2.6 Reference Handling 29
3.2.7 Tuning the Drive Closed-loop Controller 30
3.2.8 Manual PI Adjustment 30
3.3 Ambient Running Conditions 30
3.4 General Aspects of EMC 36
3.4.1 Overview of EMC Emissions 36
3.4.2 Emission Requirements 37
3.4.3 EMC Emission Test Results 39
3.4.4 Overview of Harmonics Emission 40
3.4.5 Harmonics Emission Requirements 40
3.4.6 Harmonics Test Results (Emission) 40
3.4.7 Immunity Requirements 42
3.5 Galvanic Isolation (PELV) 42
3.6 Earth Leakage Current 43
3.7 Extreme Running Conditions 43
3.7.1 Motor Thermal Protection (ETR) 44
3.7.2 Thermistor Inputs 44
4 Selection and Ordering 46
4.1 Type Code 46
4.2 Options and Accessories 47
4.2.1 Local Control Panel (LCP) 47
4.2.2 Mounting of LCP in Panel Front 47
4.2.3 IP21/NEMA Type 1 Enclosure Kit 48
4.2.4 Decoupling Plate 49
4.3 Ordering Numbers 50
4.3.1 Options and Accessories 50
4.3.2 Harmonic Filters 51
4.3.3 External RFI Filter 52
5 Installation 53
5.1 Electrical Installation 53
5.1.1 Electrical Installation in General 54
Contents VLT®HVAC Basic Drive FC 101
2 Danfoss A/S © 04/2016 All rights reserved. MG18C702

5.1.2 Mains and Motor Connection 55
5.1.3 EMC-compliant Electrical Installation 60
5.1.4 Control Terminals 62
6 Programming 63
6.1 Introduction 63
6.2 Local Control Panel (LCP) 63
6.3 Menus 64
6.3.1 Status Menu 64
6.3.2 Quick Menu 64
6.3.3 Main Menu 78
6.4 Quick Transfer of Parameter Settings between Multiple Frequency Converters 78
6.5 Readout and Programming of Indexed Parameters 79
6.6 Initialization to Default Settings 79
7 RS485 Installation and Set-up 80
7.1 RS485 80
7.1.1 Overview 80
7.1.2 Network Connection 80
7.1.3 Frequency Converter Hardware Set-up 81
7.1.4 Parameter Settings for Modbus Communication 81
7.1.5 EMC Precautions 82
7.2 FC Protocol 82
7.2.1 Overview 82
7.2.2 FC with Modbus RTU 82
7.3 Parameter Settings to Enable the Protocol 83
7.4 FC Protocol Message Framing Structure 83
7.4.1 Content of a Character (Byte) 83
7.4.2 Telegram Structure 83
7.4.3 Telegram Length (LGE) 83
7.4.4 Frequency Converter Address (ADR) 83
7.4.5 Data Control Byte (BCC) 83
7.4.6 The Data Field 83
7.4.7 The PKE Field 84
7.4.8 Parameter Number (PNU) 84
7.4.9 Index (IND) 84
7.4.10 Parameter Value (PWE) 85
7.4.11 Data Types Supported by the Frequency Converter 85
7.4.12 Conversion 85
7.4.13 Process Words (PCD) 85
7.5 Examples 85
Contents Design Guide
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7.5.1 Writing a Parameter Value 85
7.5.2 Reading a Parameter Value 86
7.6 Modbus RTU Overview 86
7.6.1 Introduction 86
7.6.2 Overview 86
7.6.3 Frequency Converter with Modbus RTU 87
7.7 Network Conguration 87
7.8 Modbus RTU Message Framing Structure 87
7.8.1 Introduction 87
7.8.2 Modbus RTU Telegram Structure 87
7.8.3 Start/Stop Field 88
7.8.4 Address Field 88
7.8.5 Function Field 88
7.8.6 Data Field 88
7.8.7 CRC Check Field 88
7.8.8 Coil Register Addressing 88
7.8.9 Access via PCD write/read 90
7.8.10 How to Control the Frequency Converter 91
7.8.11 Function Codes Supported by Modbus RTU 91
7.8.12 Modbus Exception Codes 91
7.9 How to Access Parameters 92
7.9.1 Parameter Handling 92
7.9.2 Storage of Data 92
7.9.3 IND (Index) 92
7.9.4 Text Blocks 92
7.9.5 Conversion Factor 92
7.9.6 Parameter Values 92
7.10 Examples 92
7.10.1 Read Coil Status (01 hex) 92
7.10.2 Force/Write Single Coil (05 hex) 93
7.10.3 Force/Write Multiple Coils (0F hex) 94
7.10.4 Read Holding Registers (03 hex) 94
7.10.5 Preset Single Register (06 hex) 94
7.10.6 Preset Multiple Registers (10 hex) 95
7.10.7 Read/Write Multiple Registers (17 hex) 95
7.11 Danfoss FC Control Prole 96
7.11.1 Control Word According to FC Prole (8–10 Protocol = FC Prole) 96
7.11.2 Status Word According to FC Prole (STW) 97
7.11.3 Bus Speed Reference Value 98
8 General Specications 100
Contents VLT®HVAC Basic Drive FC 101
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8.1 Mechanical Dimensions 100
8.1.1 Side-by-side Installation 100
8.1.2 Frequency Converter Dimensions 101
8.1.3 Shipping Dimensions 103
8.1.4 Field Mounting 104
8.2 Mains Supply Specications 105
8.2.1 3x200–240 V AC 105
8.2.2 3x380–480 V AC 106
8.2.3 3x525–600 V AC 110
8.3 Fuses and Circuit Breakers 111
8.4 General Technical Data 113
8.4.1 Mains Supply (L1, L2, L3) 113
8.4.2 Motor Output (U, V, W) 113
8.4.3 Cable Length and Cross-section 113
8.4.4 Digital Inputs 114
8.4.5 Analog Inputs 114
8.4.6 Analog Output 114
8.4.7 Digital Output 114
8.4.8 Control Card, RS485 Serial Communication 115
8.4.9 Control Card, 24 V DC Output 115
8.4.10 Relay Output 115
8.4.11 Control Card, 10 V DC Output 115
8.4.12 Ambient Conditions 115
8.5 dU/Dt 116
Index 119
Contents Design Guide
MG18C702 Danfoss A/S © 04/2016 All rights reserved. 5

1 Introduction
1.1 Purpose of the Design Guide
This design guide is intended for project and systems
engineers, design consultants, and application and product
specialists. Technical information is provided to understand
the capabilities of the frequency converter for integration
into motor control and monitoring systems. Details
concerning operation, requirements, and recommendations
for system integration are described. Information is proved
for input power characteristics, output for motor control,
and ambient operating conditions for the frequency
converter.
Also included are:
•Safety features.
•Fault condition monitoring.
•Operational status reporting.
•Serial communication capabilities.
•Programmable options and features.
Also provided are design details such as:
•Site requirements.
•Cables.
•Fuses.
•Control wiring.
•Unit sizes and weights.
•Other critical information necessary to plan for
system integration.
Reviewing the detailed product information in the design
stage enables developing a well-conceived system with
optimal functionality and eciency.
VLT®is a registered trademark.
1.2 Document and Software Version
This manual is regularly reviewed and updated. All
suggestions for improvement are welcome.
Edition Remarks Software version
MG18C7xx Update to new software version 2.8x
Table 1.1 Document and Software Version
1.3 Safety Symbols
The following symbols are used in this guide:
WARNING
Indicates a potentially hazardous situation that could
result in death or serious injury.
CAUTION
Indicates a potentially hazardous situation that could
result in minor or moderate injury. It can also be used to
alert against unsafe practices.
NOTICE
Indicates important information, including situations that
can result in damage to equipment or property.
1.4 Abbreviations
°CDegrees Celsius
°FDegrees Fahrenheit
A Ampere/AMP
AC Alternating current
AMA Automatic motor adaptation
AWG American wire gauge
DC Direct current
EMC Electro magnetic compatibility
ETR Electronic thermal relay
FC Frequency converter
fM,N Nominal motor frequency
kg Kilogram
Hz Hertz
IINV Rated inverter output current
ILIM Current limit
IM,N Nominal motor current
IVLT,MAX The maximum output current
IVLT,N The rated output current supplied by the
frequency converter
kHz Kilohertz
LCP Local control panel
m Meter
mA Milliampere
MCT Motion control tool
mH Millihenry inductance
min Minute
ms Millisecond
nF Nanofarad
Nm Newton meters
nsSynchronous motor speed
Introduction VLT®HVAC Basic Drive FC 101
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PM,N Nominal motor power
PCB Printed circuit board
PELV Protective extra low voltage
Regen Regenerative terminals
RPM Revolutions per minute
s Second
TLIM Torque limit
UM,N Nominal motor voltage
V Volts
Table 1.2 Abbreviations
1.5 Additional Resources
•VLT
®
HVAC Basic Drive FC 101 Quick Guide provides
basic information on mechanical dimensions,
installation, and programming.
•VLT
®
HVAC Basic Drive FC 101 Programming Guide
provides information on how to program, and
includes complete parameter descriptions.
•Danfoss VLT®Energy Box software. Select PC
Software Download at www.danfoss.com/Busines-
sAreas/DrivesSolutions.
VLT®Energy Box software allows energy
consumption comparisons of HVAC fans and
pumps driven by Danfoss frequency converters
and alternative methods of ow control. Use this
tool to accurately project the costs, savings, and
payback of using Danfoss frequency converters
on HVAC fans, pumps, and cooling towers.
Danfoss technical literature is available in electronic form
on the documentation CD that is shipped with the
product, or in print from your local Danfoss sales oce.
MCT 10 Set-up Software support
Download the software from www.danfoss.com/Busines-
sAreas/DrivesSolutions/Software+MCT10/
MCT10+Downloads.htm.
During the installation process of the software, enter
access code 81463800 to activate FC 101 functionality. A
licence key is not required for using FC 101 functionality.
The latest software does not always contain the latest
updates for frequency converters. Contact the local sales
oce for the latest frequency converter updates (in the
form of *.upd les), or download the frequency converter
updates from www.danfoss.com/BusinessAreas/DrivesSo-
lutions/fc101driveupdates.
1.6 Denitions
Frequency converter
IVLT, MAX
The maximum output current.
IVLT,N
The rated output current supplied by the frequency
converter.
UVLT, MAX
The maximum output voltage.
Input
The connected motor can start and stop via LCP and
digital inputs. Functions are divided into 2 groups, as
described in Table 1.3. Functions in group 1 have higher
priority than functions in group 2.
Group 1 Reset, coast stop, reset and coast stop, quick
stop, DC brake, stop, and [O].
Group 2 Start, pulse start, reversing, start reversing, jog,
and freeze output.
Table 1.3 Control Commands
Motor
fJOG
The motor frequency when the jog function is activated
(via digital terminals).
fM
The motor frequency.
fMAX
The maximum motor frequency.
fMIN
The minimum motor frequency.
fM,N
The rated motor frequency (nameplate data).
IM
The motor current.
IM,N
The rated motor current (nameplate data).
nM,N
The nominal motor speed (nameplate data).
PM,N
The rated motor power (nameplate data).
UM
The instantaneous motor voltage.
UM,N
The rated motor voltage (nameplate data).
Introduction Design Guide
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11

Break-away torque
175ZA078.10
Pull-out
rpm
Torque
Illustration 1.1 Break-away Torque
ηVLT
The eciency of the frequency converter is dened as the
ratio between the power output and the power input.
Start-disable command
A stop command belonging to the group 1 control
commands, see Table 1.3.
Stop command
See Table 1.3.
Analog reference
A signal transmitted to the analog inputs 53 or 54. It can
be voltage or current.
•Current input: 0–20 mA and 4–20 mA
•Voltage input: 0–10 V DC
Bus reference
A signal transmitted to the serial communication port (FC
port).
Preset reference
A dened preset reference to be set from -100% to +100%
of the reference range. Selection of 8 preset references via
the digital terminals.
RefMAX
Determines the relationship between the reference input at
100% full scale value (typically 10 V, 20 mA) and the
resulting reference. The maximum reference value set in
parameter 3-03 Maximum Reference.
RefMIN
Determines the relationship between the reference input at
0% value (typically 0 V, 0 mA, 4 mA) and the resulting
reference. The minimum reference value is set in
parameter 3-02 Minimum Reference.
Analog inputs
The analog inputs are used for controlling various
functions of the frequency converter.
There are 2 types of analog inputs:
•Current input: 0–20 mA and 4–20 mA
•Voltage input: 0–10 V DC
Analog outputs
The analog outputs can supply a signal of 0–20 mA, 4–
20 mA, or a digital signal.
Automatic motor adaptation, AMA
The AMA algorithm determines the electrical parameters
for the connected motor at standstill and compensates for
the resistance based on the length of the motor cable.
Digital inputs
The digital inputs can be used for controlling various
functions of the frequency converter.
Digital outputs
The frequency converter provides 2 solid-state outputs that
can supply a 24 V DC (maximum 40 mA) signal.
Relay outputs
The frequency converter provides 2 programmable relay
outputs.
ETR
Electronic thermal relay is a thermal load calculation based
on present load and time. Its purpose is to estimate the
motor temperature and prevent overheating of the motor.
Initializing
If initializing is carried out (parameter 14-22 Operation
Mode), the programmable parameters of the frequency
converter return to their default settings.
Parameter 14-22 Operation Mode does not initialize
communication parameters, fault log, or re mode log.
Intermittent duty cycle
An intermittent duty rating refers to a sequence of duty
cycles. Each cycle consists of an on-load and an o-load
period. The operation can be either periodic duty or none-
periodic duty.
LCP
The local control panel (LCP) makes up a complete
interface for control and programming of the frequency
converter. The control panel is detachable on IP20 units
and xed on IP54 units. It can be installed up to 3 m (9.8
ft) from the frequency converter, that is, in a front panel
with the installation kit option.
Lsb
Least signicant bit.
MCM
Short for mille circular mil, an American measuring unit for
cable cross-section. 1 MCM = 0.5067 mm2.
Msb
Most signicant bit.
On-line/O-line parameters
Changes to on-line parameters are activated immediately
after the data value is changed. Press [OK] to activate o-
line parameters.
Introduction VLT®HVAC Basic Drive FC 101
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PI controller
The PI controller maintains the desired speed, pressure,
temperature, and so on, by adjusting the output frequency
to match the varying load.
RCD
Residual current device.
Set-up
Parameter settings in 2 set-ups can be saved. Change
between the 2 parameter set-ups and edit 1 set-up, while
another set-up is active.
Slip compensation
The frequency converter compensates for the motor slip by
giving the frequency a supplement that follows the
measured motor load keeping the motor speed almost
constant.
Smart logic control (SLC)
The SLC is a sequence of user-dened actions executed
when the associated user-dened events are evaluated as
true by the SLC.
Thermistor
A temperature-dependent resistor placed where the
temperature is to be monitored (frequency converter or
motor).
Trip
A state entered in fault situations, for example, if the
frequency converter is subject to an overtemperature or
when the frequency converter is protecting the motor,
process, or mechanism. Restart is prevented until the cause
of the fault does not exist and the trip state is canceled by
activating reset or, sometimes, by being programmed to
reset automatically. Do not use trip for personal safety.
Trip lock
A state entered in fault situations when the frequency
converter is protecting itself and requiring physical
intervention, for example, if the frequency converter is
subject to a short circuit on the output. A locked trip can
only be canceled by cutting o mains, removing the cause
of the fault, and reconnecting the frequency converter.
Restart is prevented until the trip state is canceled by
activating reset or, sometimes, by being programmed to
reset automatically. Do not use trip lock for personal safety.
VT characteristics
Variable torque characteristics used for pumps and fans.
VVC+
If compared with standard voltage/frequency ratio control,
voltage vector control (VVC+) improves the dynamics and
the stability, both when the speed reference is changed
and in relation to the load torque.
1.7 Power Factor
The power factor indicates to which extent the frequency
converter imposes a load on the mains supply. The power
factor is the ratio between I1and IRMS, where I1is the
fundamental current, and IRMS is the total RMS current
including harmonic currents. The lower the power factor,
the higher the IRMS for the same kW performance.
Powerfactor =3 × U×I1 × COSϕ
3 × U×IRMS
The power factor for 3-phase control:
Powerfactor =I1×cosϕ1
IRMS
=I1
IRMS
sincecosϕ1 = 1
IRMS =I1
2+I5 2+I7 2 +  .  .  + In 2
A high-power factor indicates that the dierent harmonic
currents are low.
The frequency converters built-in DC coils produce a high-
power factor, which minimizes the imposed load on the
mains supply.
1.8 Regulatory Compliance
Frequency converters are designed in compliance with the
directives described in this section.
1.8.1 CE Mark
The CE mark (Communauté Européenne) indicates that the
product manufacturer conforms to all applicable EU
directives. The EU directives applicable to the design and
manufacture of frequency converters are listed in Table 1.4.
NOTICE
The CE mark does not regulate the quality of the
product. Technical specications cannot be deduced from
the CE mark.
NOTICE
Frequency converters with an integrated safety function
must comply with the machinery directive.
EU directive Version
Low Voltage Directive 2014/35/EU
EMC Directive 2014/30/EU
ErP Directive
Table 1.4 EU Directives Applicable to Frequency Converters
Declarations of conformity are available on request.
Introduction Design Guide
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11

1.8.1.1 Low Voltage Directive
The low voltage directive applies to all electrical
equipment in the 50–1000 V AC and the 75–1600 V DC
voltage ranges.
The aim of the directive is to ensure personal safety and
avoid property damage, when operating electrical
equipment that is installed and maintained correctly, in its
intended application.
1.8.1.2 EMC Directive
The purpose of the EMC (electromagnetic compatibility)
directive is to reduce electromagnetic interference and
enhance immunity of electrical equipment and instal-
lations. The basic protection requirement of the EMC
Directive 2014/30/EU states that devices that generate
electromagnetic interference (EMI), or whose operation
could be aected by EMI, must be designed to limit the
generation of electromagnetic interference and shall have
a suitable degree of immunity to EMI when properly
installed, maintained, and used as intended.
Electrical equipment devices used alone or as part of a
system must bear the CE mark. Systems do not require the
CE mark, but must comply with the basic protection
requirements of the EMC directive.
1.8.1.3 ErP Directive
The ErP directive is the European Ecodesign Directive for
energy-related products. The directive sets ecodesign
requirements for energy-related products, including
frequency converters. The directive aims at increasing
energy eciency and the level of protection of the
environment, while increasing the security of the energy
supply. Environmental impact of energy-related products
includes energy consumption throughout the entire
product life cycle.
1.8.2 UL Compliance
UL-listed
Illustration 1.2 UL
NOTICE
IP54 units are not certied for UL.
The frequency converter complies with UL 508C thermal
memory retention requirements. For more information,
refer to the section Motor Thermal Protection in the
product-specic design guide.
1.8.3 RCM Mark Compliance
Illustration 1.3 RCM Mark
The RCM Mark label indicates compliance with the
applicable technical standards for Electromagnetic Compat-
ibility (EMC). An RCM Mark label is required for placing
electrical and electronic devices on the market in Australia
and New Zealand. The RCM Mark regulatory arrangements
only deal with conducted and radiated emission. For
frequency converters, the emission limits specied in
EN/IEC 61800-3 apply. A declaration of conformity can be
provided on request.
Introduction VLT®HVAC Basic Drive FC 101
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11

2 Safety
2.1 Qualied Personnel
Correct and reliable transport, storage, installation,
operation, and maintenance are required for the trouble-
free and safe operation of the frequency converter. Only
qualied personnel are allowed to install or operate this
equipment.
Qualied personnel are dened as trained sta, who are
authorized to install, commission, and maintain equipment,
systems, and circuits in accordance with pertinent laws and
regulations. Also, the personnel must be familiar with the
instructions and safety measures described in this guide.
2.2 Safety Precautions
WARNING
HIGH VOLTAGE
Frequency converters contain high voltage when
connected to AC mains input, DC supply, or load sharing.
Failure to perform installation, start-up, and maintenance
by qualied personnel can result in death or serious
injury.
•Only qualied personnel must perform instal-
lation, start-up, and maintenance.
WARNING
UNINTENDED START
When the frequency converter is connected to AC mains,
DC supply, or load sharing, the motor may start at any
time. Unintended start during programming, service, or
repair work can result in death, serious injury, or
property damage. The motor can start with an external
switch, a eldbus command, an input reference signal
from the LCP or LOP, via remote operation using MCT 10
Set-up Software, or after a cleared fault condition.
To prevent unintended motor start:
•Press [O/Reset] on the LCP before
programming parameters.
•Disconnect the frequency converter from the
mains.
•Completely wire and assemble the frequency
converter, motor, and any driven equipment
before connecting the frequency converter to
AC mains, DC supply, or load sharing.
WARNING
DISCHARGE TIME
The frequency converter contains DC-link capacitors,
which can remain charged even when the frequency
converter is not powered. High voltage can be present
even when the warning LED indicator lights are o.
Failure to wait the specied time after power has been
removed before performing service or repair work can
result in death or serious injury.
•Stop the motor.
•Disconnect AC mains and remote DC-link power
supplies, including battery back-ups, UPS, and
DC-link connections to other frequency
converters.
•Disconnect or lock PM motor.
•Wait for the capacitors to discharge fully. The
minimum duration of waiting time is specied
in Table 2.1.
•Before performing any service or repair work,
use an appropriate voltage measuring device to
make sure that the capacitors are fully
discharged.
Voltage [V] Power range [kW (hp)] Minimum waiting time
(minutes)
3x200 0.25–3.7 (0.33–5) 4
3x200 5.5–11 (7–15) 15
3x400 0.37–7.5 (0.5–10) 4
3x400 11–90 (15–125) 15
3x600 2.2–7.5 (3–10) 4
3x600 11–90 (15–125) 15
Table 2.1 Discharge Time
WARNING
LEAKAGE CURRENT HAZARD
Leakage currents exceed 3.5 mA. Failure to ground the
frequency converter properly can result in death or
serious injury.
•Ensure the correct grounding of the equipment
by a certied electrical installer.
Safety Design Guide
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22

WARNING
EQUIPMENT HAZARD
Contact with rotating shafts and electrical equipment
can result in death or serious injury.
•Ensure that only trained and qualied personnel
perform installation, start-up, and maintenance.
•Ensure that electrical work conforms to national
and local electrical codes.
•Follow the procedures in this manual.
CAUTION
INTERNAL FAILURE HAZARD
An internal failure in the frequency converter can result
in serious injury when the frequency converter is not
properly closed.
•Ensure that all safety covers are in place and
securely fastened before applying power.
Safety VLT®HVAC Basic Drive FC 101
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22

3 Product Overview
3.1 Advantages
3.1.1 Why use a Frequency Converter for
Controlling Fans and Pumps?
A frequency converter takes advantage of the fact that
centrifugal fans and pumps follow the laws of propor-
tionality for such fans and pumps. For further information,
see chapter 3.1.3 Example of Energy Savings.
3.1.2 The Clear Advantage - Energy Savings
The clear advantage of using a frequency converter for
controlling the speed of fans or pumps lies in the
electricity savings.
When comparing with alternative control systems and
technologies, a frequency converter is the optimum energy
control system for controlling fan and pump systems.
130BA780.11
SYSTEM CURVE
FAN CURVE
PRESSURE %
A
B
C
0
20
40
60
80
100
120
20 40 60 80 100 120 140 160 180
VOLUME %
Illustration 3.1 Fan Curves (A, B, and C) for Reduced Fan
Volumes
120
100
80
60
40
20
020 40 60 80 100 120 140 160 180
120
100
80
60
40
20
0 20 40 60 80 100 120 140 160 180
Volume %
Volume %
INPUT POWER % PRESSURE %
SYSTEM CURVE
FAN CURVE
A
B
C
130BA781.11
ENERGY
CONSUMED
Illustration 3.2 Energy Savings with Frequency Converter
Solution
When using a frequency converter to reduce fan capacity
to 60% - more than 50% energy savings may be obtained
in typical applications.
3.1.3 Example of Energy Savings
As shown in Illustration 3.3, the ow is controlled by
changing the RPM. By reducing the speed by only 20%
from the rated speed, the ow is also reduced by 20%.
This is because the ow is directly proportional to the
RPM. The consumption of electricity, however, is reduced
by 50%.
If the system in question only needs to be able to supply a
ow that corresponds to 100% a few days in a year, while
the average is below 80% of the rated ow for the
remainder of the year, the amount of energy saved is even
more than 50%.
Illustration 3.3 describes the dependence of ow, pressure,
and power consumption on RPM.
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33

n
100%
50%
25%
12,5%
50% 100%
80%
80%
175HA208.10
Power ~n
3
Pressure ~n
2
Flow ~n
Illustration 3.3 Laws of Proportionally
Flow:  Q1
Q2
=n1
n2
Pressure: H1
H2
 =  n1
n2
2
Power:  P1
P2
= n1
n2
3
Q = Flow P = Power
Q1= Rated ow P1= Rated power
Q2= Reduced ow P2= Reduced power
H = Pressure n = Speed control
H1= Rated pressure n1= Rated speed
H2= Reduced pressure n2= Reduced speed
Table 3.1 The Laws of Proportionality
3.1.4 Comparison of Energy Savings
The Danfoss frequency converter solution oers major
savings compared with traditional energy saving solutions
such as discharge damper solution and inlet guide vanes
(IGV) solution. This is because the frequency converter is
able to control fan speed according to thermal load on the
system, and the frequency converter has a built-in facility
that enables the frequency converter to function as a
building management system, BMS.
Illustration 3.3 shows typical energy savings obtainable
with 3 well-known solutions when fan volume is reduced
to 60%.
As the graph shows, more than 50% energy savings can be
achieved in typical applications.
130BA782.10
Discharge
damper
Less energy savings
IGV
Costlier installation
Maximum energy savings
Illustration 3.4 The 3 Common Energy Saving Systems
130BA779.12
0 60 0 60 0 60
0
20
40
60
80
100
Discharge Damper Solution
IGV Solution
VLT Solution
Energy consumed
Energy consumed
Energy consumed
Input power %
Volume %
Illustration 3.5 Energy Savings
Discharge dampers reduce power consumption. Inlet guide
vanes oer a 40% reduction, but are expensive to install.
The Danfoss frequency converter solution reduces energy
consumption with more than 50% and is easy to install. It
also reduces noise, mechanical stress, and wear-and-tear,
and extends the life span of the entire application.
Product Overview VLT®HVAC Basic Drive FC 101
14 Danfoss A/S © 04/2016 All rights reserved. MG18C702
33

3.1.5 Example with Varying Flow over 1
Year
This example is calculated based on pump characteristics
obtained from a pump datasheet.
The result obtained shows energy savings of more than
50% at the given ow distribution over a year. The
payback period depends on the price per kWh and the
price of frequency converter. In this example, it is less than
a year when compared with valves and constant speed.
Energy savings
Pshaft = Pshaft output
500
[h] t
1000
1500
2000
200100 300 [m
3
/h]
400
Q
175HA210.11
Illustration 3.6 Flow Distribution over 1 Year
175HA209.11
60
50
40
30
20
10
Hs
0 100 200 300 400
(mwg)
B
C
A
750rpm
1050rpm
1350rpm
1650rpm
0
10
20
30
(kW)
40
50
60
200100 300 (m
3
/h)
(m
3
/h)
400
750rpm
1050rpm
1350rpm
1650rpm
Pshaft
C
1
B
1
A
1
Illustration 3.7 Energy
m3/
h
Distri-
bution Valve regulation Frequency converter control
% Hours Power Consump-
tion Power Consump- tion
A1- B1kWh A1- C1kWh
350 5 438 42.5 18.615 42.5 18.615
300 15 1314 38.5 50.589 29.0 38.106
250 20 1752 35.0 61.320 18.5 32.412
200 20 1752 31.5 55.188 11.5 20.148
150 20 1752 28.0 49.056 6.5 11.388
100 20 1752 23.0 40.296 3.5 6.132
Σ100 8760 – 275.064 – 26.801
Table 3.2 Result
3.1.6 Better Control
If a frequency converter is used for controlling the ow or
pressure of a system, improved control is obtained.
A frequency converter can vary the speed of the fan or
pump, obtaining variable control of ow and pressure.
Furthermore, a frequency converter can quickly adapt the
speed of the fan or pump to new ow or pressure
conditions in the system.
Simple control of process (ow, level, or pressure) utilizing
the built-in PI control.
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MG18C702 Danfoss A/S © 04/2016 All rights reserved. 15
33

3.1.7 Star/Delta Starter or Soft Starter not
Required
When larger motors are started, it is necessary in many
countries to use equipment that limits the start-up current.
In more traditional systems, a star/delta starter or soft
starter is widely used. Such motor starters are not required
if a frequency converter is used.
As illustrated in Illustration 3.8, a frequency converter does
not consume more than rated current.
Full load
% Full-load current
& speed
500
100
0
0 12,5 25 37,5 50Hz
200
300
400
600
700
800
4
3
2
1
175HA227.10
1VLT®HVAC Basic Drive FC 101
2 Star/delta starter
3 Soft starter
4 Start directly on mains
Illustration 3.8 Start-up Current
3.1.8 Using a Frequency Converter Saves
Money
The example in chapter 3.1.9 Without a Frequency Converter
shows that a frequency converter replaces other
equipment. It is possible to calculate the cost of installing
the 2 dierent systems. In the example, the 2 systems can
be established at roughly the same price.
Use the VLT®Energy Box software that is introduced in
chapter 1.5 Additional Resources to calculate the cost
savings that can be achieved by using a frequency
converter.
Product Overview VLT®HVAC Basic Drive FC 101
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33

3.1.9 Without a Frequency Converter
M
- +
M
M
x6 x6
x6
175HA205.12
Valve
posi-
tion
Starter
Fuses
LV
supply
P.F.C
Flow
3-Port
valve
Bypass
Return Control
Supply
air
V.A.V
outlets
Duct
P.F.C
Mains
Fuses
Starter
Bypass
supply
LV
Return
valve
3-Port
Flow Control
Valve
posi-
tion
Starter
Power
Factor
Correction
Mains
IGV
Mechanical
linkage
and vanes
Fan
Motor
or
actuator
Main
B.M.S
Local
D.D.C.
control
Sensors
PT
Pressure
control
signal
0/10V
Temperature
control
signal
0/10V
Control
Mains
Cooling section Heating section Fan sectionInlet guide vane
Pump Pump
D.D.C. Direct digital control
E.M.S. Energy management system
V.A.V. Variable air volume
Sensor P Pressure
Sensor T Temperature
Illustration 3.9 Traditional Fan System
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33

3.1.10 With a Frequency Converter
175HA206.11
Pump
Flow
Return
Supply
air
V.A.V
outlets
Duct
Mains
Pump
Return Flow
Mains
Fan
Main
B.M.S
Local
D.D.C.
control
Sensors
Mains
Cooling section Heating section Fan section
Pressure
control
0-10V
or
0/4-20mA
Control
temperature
0-10V
or
0/4-20mA
Control
temperature
0-10V
or
0/4-20mA
VLT
M
- +
VLT
M
M
PT
VLT
x3 x3
x3
D.D.C. Direct digital control
E.M.S. Energy management system
V.A.V. Variable air volume
Sensor P Pressure
Sensor T Temperature
Illustration 3.10 Fan System Controlled by Frequency Converters
Product Overview VLT®HVAC Basic Drive FC 101
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33