Danfoss VLT Flow Drive FC 111 Guide

Design Guide
VLT® Flow Drive FC 111
vlt-drives.danfoss.com

1
1.1
1.2
1.2.1
1.2.2
1.3
1.4
1.4.1
1.4.2
2
2.1
2.2
2.3
3
3.1
3.1.1
3.1.1.1
3.1.1.2
3.1.1.3
3.1.1.4
3.1.1.5
3.1.1.6
3.1.1.7
3.1.1.8
3.1.1.9
3.1.2
3.1.2.1
3.1.2.2
3.1.2.3
3.1.2.4
3.1.2.5
3.1.2.6
3.1.3
3.1.4
3.1.5
Contents
Introduction 10
Purpose of this Design Guide 10
Additional Resources 10
Other Resources 10
MCT 10 Set-up Software Support 10
Document and Software Version 10
Regulatory Compliance 10
Introduction 10
CE Mark 10
Safety 12
Safety Symbols 12
Qualified Personnel 12
Safety Precautions 12
Product Overview 14
Advantages 14
Why Use a Drive for Controlling Fans and Pumps? 14
The Clear Advantage - Energy Savings 14
Example of Energy Savings 15
Comparison of Energy Savings 15
Example with Varying Flow over 1 Year 17
Better Control 18
Star/Delta Starter or Soft Starter not Required 18
Using a Drive Saves Money 18
Traditional Fan System without a Drive 19
Fan System Controlled by Drives 20
Application Examples 20
Variable Air Volume 20
Constant Air Volume 21
Cooling Tower Fan 22
Condenser Pumps 23
Primary Pumps 24
Secondary Pumps 25
Check Valve Monitoring 26
Dry Pump Detection 26
End of Curve Detection 26
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Contents
VLT® Flow Drive FC 111
Design Guide

3.1.6
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
3.2.7
3.2.8
3.2.9
3.3
3.3.1
3.3.2
3.3.2.1
3.3.2.2
3.3.3
3.4
3.4.1
3.4.2
3.4.3
3.4.4
3.4.4.1
3.4.4.2
3.4.5
3.4.6
3.4.7
3.5
3.6
3.6.1
3.7
3.7.1
3.7.2
3.7.3
3.7.3.1
3.7.3.2
Time-based Functions 26
Control Structures 26
Introduction 26
Control Structure Open Loop 27
PM/EC+ Motor Control 27
Local (Hand On) and Remote (Auto On) Control 27
Control Structure Closed Loop 28
Feedback Conversion 28
Reference Handling 28
Tuning the Drive Closed-loop 29
Adjusting the Manual PI 29
Ambient Running Conditions 30
Air Humidity 30
Acoustic Noise or Vibration 30
Acoustic Noise 30
Vibration and Shock 31
Aggressive Environments 31
General Aspects of EMC 31
Overview of EMC Emissions 31
Emission Requirements 32
EMC Emission Test Results 33
Harmonics Emission 34
Harmonics Emission Requirements 34
Harmonics Test Results (Emission) 35
Harmonics Emission Requirements 34
Harmonics Test Results (Emission) 36
Immunity Requirements 37
Galvanic Isolation (PELV) 37
Ground Leakage Current 38
Using a Residual Current Device (RCD) 40
Extreme Running Conditions 41
Introduction 41
Motor Thermal Protection (ETR) 42
Thermistor Inputs 42
Example with Digital Input and 10 V Power Supply 43
Example with Analog Input and 10 V Power Supply 43
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Contents
VLT® Flow Drive FC 111
Design Guide

4
4.1
4.2
4.2.1
4.2.2
4.2.3
4.3
4.3.1
4.3.2
4.3.3
5
5.1
5.2
5.2.1
5.3
5.3.1
5.3.2
5.3.3
5.3.4
5.3.5
5.3.6
5.4
5.4.1
5.4.2
5.4.3
5.4.4
6
6.1
6.2
6.3
6.4
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5
6.5
Selection and Ordering 45
Type Code 45
Options and Accessories 46
Local Control Panel (LCP) 46
IP21 Enclosure Kit 46
Decoupling Plate 48
Ordering Numbers 49
Options and Accessories 49
Harmonic Filters 50
External RFI Filter 51
Mechanical Installation Considerations 53
Power Ratings, Weights, and Dimensions 53
Mechanical Installation H1-H8 55
Side-by-side Installation 55
Mechanical Installation H13-H14 56
Tools Needed 56
Installation and Cooling Requirements 56
Lifting the Drive 57
Wall Mounting the Drive 58
Creating Cable Openings 59
Back-channel Cooling 59
Derating 60
Manual Derating and Automatic Derating 60
Derating for Low-speed Operation 60
Derating for Low Air Pressure and High Altitudes 60
Derating for Ambient Temperature and Switching Frequency 60
Electrical Installation Considerations 63
Safety Instructions 63
Electrical Wiring 64
EMC-compliant Electrical Installation 64
Relays and Terminals 66
Relays and Terminals on Enclosure Sizes H1–H5 66
Relays and Terminals on Enclosure Size H6 67
Relays and Terminals on Enclosure Size H7 67
Relays and Terminals on Enclosure Size H8 68
Relays and Terminals on Enclosure Size H13–H14 69
View of Control Shelf 69
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Contents
VLT® Flow Drive FC 111
Design Guide

6.6
6.7
6.8
6.8.1
6.8.2
6.8.3
6.8.4
6.9
6.9.1
6.9.2
6.9.3
6.9.4
6.9.5
6.10
6.11
6.11.1
6.11.2
6.11.3
6.12
6.12.1
6.12.2
6.12.3
6.12.4
7
7.1
7.2
7.2.1
7.2.2
7.2.2.1
7.2.2.2
7.2.2.3
7.2.2.4
7.2.2.5
7.2.2.6
7.2.2.7
7.2.2.8
7.2.3
Fastener Tightening Torques 70
IT Mains 71
Mains and Motor Connection 72
Introduction 72
Connecting to the Ground 72
Connecting the Motor 73
Connecting the AC Mains 73
Fuses and Circuit Breakers 73
Branch Circuit Protection 73
Short-circuit Protection 73
Overcurrent Protection 74
CE Compliance 74
Recommendation of Fuses and Circuit Breakers 74
Control Terminals 75
Efficiency 76
Efficiency of the Drive 76
Efficiency of the Motor 77
Efficiency of the System 77
dU/dt Conditions 77
dU/dt Overview 77
dU/dt Test Results for H1–H8 77
High-power Range 80
dU/dt Test Results for H13–H14 80
Programming 81
Local Control Panel (LCP) 81
Menus 82
Status Menu 82
Quick Menu 82
Quick Menu Introduction 82
Setup Wizard Introduction 83
Setup Wizard for Open-loop Applications 84
Setup Wizard for Closed-loop Applications 89
Motor Setup 94
Changes Made Function 97
Changing Parameter Settings 98
Accessing All Parameters via the Main Menu 98
Main Menu 98
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Contents
VLT® Flow Drive FC 111
Design Guide

7.3
7.3.1
7.3.2
7.4
7.5
7.5.1
7.5.2
8
8.1
8.1.1
8.1.2
8.1.3
8.1.4
8.1.5
8.2
8.2.1
8.2.2
8.3
8.4
8.4.1
8.4.2
8.4.3
8.4.4
8.4.5
8.4.6
8.4.7
8.4.8
8.4.9
8.4.10
8.4.11
8.4.12
8.4.13
8.5
8.5.1
8.5.2
8.6
8.6.1
Quick Transfer of Parameter Settings between Multiple Drives 98
Transferring Data from the Drive to the LCP 98
Transferring Data from the LCP to the Drive 98
Readout and Programming of Indexed Parameters 99
Initialization to Default Settings 99
Recommended Initialization 99
Two-finger Initialization 99
RS485 Installation and Set-up 101
RS485 101
Overview 101
Connecting the Drive to the RS485 Network 102
Hardware Set-up 102
Parameter Settings for Modbus Communication 103
EMC Precautions 103
FC Protocol 104
Overview 104
FC with Modbus RTU 104
Network Configuration 105
FC Protocol Message Framing Structure 105
Content of a Character (byte) 105
Telegram Structure 105
Telegram Length (LGE) 105
Drive Address (ADR) 106
Data Control Byte (BCC) 106
The Data Field 106
The PKE Field 107
Parameter Number (PNU) 108
Index (IND) 108
Parameter Value (PWE) 108
Data Types Supported by the Drive 109
Conversion 109
Process Words (PCD) 110
Examples 110
Writing a Parameter Value 110
Reading a Parameter Value 110
Modbus RTU 111
Prerequisite Knowledge 111
AJ363928382091en-000101/130R0983 | 7Danfoss A/S © 2021.04
Contents
VLT® Flow Drive FC 111
Design Guide

8.6.2
8.6.3
8.7
8.8
8.8.1
8.8.2
8.8.3
8.8.4
8.8.5
8.8.6
8.8.7
8.8.8
8.8.8.1
8.8.8.2
8.8.8.3
8.8.8.4
8.8.8.5
8.8.9
8.8.10
8.8.10.1
8.8.10.2
8.8.10.3
8.9
8.9.1
8.9.2
8.9.3
8.9.4
8.9.5
8.9.6
8.10
8.10.1
8.10.2
8.10.3
8.10.4
8.10.5
8.10.6
8.10.7
8.10.8
Modbus RTU Overview 111
Drive with Modbus RTU 111
Network Configuration 112
Modbus RTU Message Framing Structure 112
Modbus RTU Message Byte Format 112
Modbus RTU Telegram Structure 113
Start/Stop Field 113
Address Field 113
Function Field 113
Data Field 113
CRC Check Field 113
Coil Register Addressing 114
Introduction 114
Coil Register 114
Drive Control Word (FC Profile) 114
Drive Status Word (FC Profile) 115
Address/Registers 115
Access via PCD Write/read 116
How to Control the Drive 117
Introduction 117
Function Codes Supported by Modbus RTU 117
Modbus Exception Codes 118
How to Access Parameters 118
Parameter Handling 118
Storage of Data 118
IND (Index) 119
Text Blocks 119
Conversion Factor 119
Parameter Values 119
Examples 119
Introduction 119
Read Coil Status (01 hex) 119
Force/Write Single Coil (05 hex) 120
Force/Write Multiple Coils (0F hex) 121
Read Holding Registers (03 hex) 122
Preset Single Register (06 hex) 122
Preset Multiple Registers (10 hex) 123
Read/Write Multiple Registers (17 hex) 124
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Contents
VLT® Flow Drive FC 111
Design Guide

8.11
8.11.1
8.11.2
8.11.3
8.11.4
8.11.5
9
9.1
9.1.1
9.2
9.2.1
9.2.2
9.2.3
9.2.4
9.2.5
9.2.6
9.2.7
9.2.8
9.2.9
9.2.10
9.2.11
9.2.12
9.2.13
9.2.14
10
10.1
10.2
10.2.1
10.2.2
10.2.3
10.2.4
10.2.5
Danfoss FC Control Profile 125
Control Word According to FC Profile (8-10 Protocol = FC Profile) 125
Explanation of Each Control Bit 126
Status Word According to FC Profile (STW) 128
Explanation of Each Status Bit 128
Bus Speed Reference Value 130
General Specifications 131
Mains Supply 131
3x380–480 V AC 131
General Technical Data 133
Protection and Features 133
Mains Supply 133
Motor Output (U, V, W) 133
Cable Length and Cross-section 134
Digital Inputs 134
Analog Inputs 134
Analog Outputs 135
Digital Output 135
RS485 Serial Communication 135
24 V DC Output 135
Relay Output 135
10 V DC Output 136
Ambient Conditions (H1–H8) 136
Ambient Conditions (H13–H14) 137
Appendix 138
Abbreviations 138
Definitions 139
AC Drive 139
Input 139
Motor 139
References 141
Miscellaneous 141
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Contents
VLT® Flow Drive FC 111
Design Guide

•
•
•
•
•
•
1 Introduction
1.1 Purpose of this Design Guide
This Design Guide is intended for qualified personnel, such as:
Project and systems engineers.
Design consultants.
Application and product specialists.
The Design Guide provides technical information to understand the capabilities of the VLT® Flow Drive FC 111 for integration into
motor control and monitoring systems. Its purpose is to provide design considerations and planning data for integration of the
drive into a system. It caters for selection of drives and options for a diversity of applications and installations. Reviewing the de-
tailed product information in the design stage enables developing a well-conceived system with optimal functionality and efficien-
cy.
This manual is targeted at a worldwide audience. Therefore, wherever occurring, both SI and imperial units are shown.
VLT®is a registered trademark for Danfoss A/S.
1.2 Additional Resources
1.2.1 Other Resources
Other resources are available to understand advanced drive functions and programming.
VLT® Flow Drive FC 111 Operating Guide provides basic information on mechanical dimensions, installation, and programming.
VLT® Flow Drive FC 111 Programming Guide provides information on how to program, and includes complete parameter de-
scriptions.
Danfoss VLT® Energy Box software. Select PC Software Download at www.danfoss.com.
VLT® Energy Box software allows energy consumption comparisons of HVAC fans and pumps driven by Danfoss drives and alterna-
tive methods of flow control. Use this tool to accurately project the costs, savings, and payback of using Danfoss drives on HVAC
fans, pumps, and cooling towers.
Supplementary publications and manuals are available from Danfoss website www.danfoss.com.
1.2.2 MCT 10 Set-up Software Support
Download the software from the service and support section on www.danfoss.com.
During the installation process of the software, enter access code 81462700 to activate the VLT® Flow Drive FC 111 functionality. A
license key is not required for using the VLT® Flow Drive FC 111 functionality.
The latest software does not always contain the latest updates for drives. Contact the local sales office for the latest drive updates (in
the form of *.OSS files).
1.3 Document and Software Version
This guide is regularly reviewed and updated. All suggestions for improvement are welcome.
The original language of this manual is English.
Table 1: Document and Software Version
Edition
Remarks
Software version
AJ363928382091, version 0101
First edition.
65.00
1.4 Regulatory Compliance
1.4.1 Introduction
AC drives are designed in compliance with the directives described in this section.
1.4.2 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 drives are listed in the following table.
AJ363928382091en-000101 / 130R098310 | Danfoss A/S © 2021.04
Introduction
VLT® Flow Drive FC 111
Design Guide

NOTICE
The CE mark does not regulate the quality of the product. Technical specifications cannot be deduced from the CE mark.
NOTICE
Drives with an integrated safety function must comply with the machinery directive.
Table 2: EU Directives Applicable to Drives
EU directive
Version
Low Voltage Directive
2014/35/EU
EMC Directive
2014/30/EU
ErP Directive
Declarations of conformity are available on request.
1.4.2.1 Low Voltage Directive
The aim of the Low Voltage Directive is to protect persons, domestic animals and property against dangers caused by the electrical
equipment, when operating electrical equipment that is installed and maintained correctly, in its intended application. The directive
applies to all electrical equipment in the 50–1000 V AC and the 75–1500 V DC voltage ranges.
1.4.2.2 EMC Directive
The purpose of the EMC (electromagnetic compatibility) Directive is to reduce electromagnetic interference and enhance immunity
of electrical equipment and installations. The basic protection requirement of the EMC Directive states that devices that generate
electromagnetic interference (EMI), or whose operation could be affected by EMI, must be designed to limit the generation of elec-
tromagnetic 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.
1.4.2.3 ErP Directive
The ErP Directive is the European Ecodesign Directive for energy-related products. The directive sets ecodesign requirements for
energy-related products, including drives, and aims at reducing the energy consumption and environmental impact of products by
establishing minimum energy-efficiency standards.
AJ363928382091en-000101 / 130R0983 | 11Danfoss A/S © 2021.04
Introduction
VLT® Flow Drive FC 111
Design Guide

•
•
•
•
-
-
-
-
2 Safety
2.1 Safety Symbols
The following symbols are used in this manual:
DANGER
Indicates a hazardous situation which, if not avoided, will result in death or serious injury.
WARNING
Indicates a hazardous situation which, if not avoided, could result in death or serious injury.
CAUTION
Indicates a hazardous situation which, if not avoided, could result in minor or moderate injury.
NOTICE
Indicates information considered important, but not hazard-related (for example, messages relating to property damage).
2.2 Qualified Personnel
To allow trouble-free and safe operation of the unit, only qualified personnel with proven skills are allowed to transport, store, as-
semble, install, program, commission, maintain, and decommission this equipment.
Persons with proven skills:
Are qualified electrical engineers, or persons who have received training from qualified electrical engineers and are suitably
experienced to operate devices, systems, plant, and machinery in accordance with pertinent laws and regulations.
Are familiar with the basic regulations concerning health and safety/accident prevention.
Have read and understood the safety guidelines given in all manuals provided with the unit, especially the instructions given in
the Operating Guide.
Have good knowledge of the generic and specialist standards applicable to the specific application.
2.3 Safety Precautions
WARNING
HAZARDOUS VOLTAGE
AC drives contain hazardous voltage when connected to the AC mains or connected on the DC terminals. Failure to perform
installation, start-up, and maintenance by skilled personnel can result in death or serious injury.
Only skilled personnel must perform installation, start-up, and maintenance.
WARNING
UNINTENDED START
When the drive 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. Start the motor with an external
switch, a fieldbus command, an input reference signal from the local control panel (LCP), via remote operation using MCT 10
software, or after a cleared fault condition.
Disconnect the drive from the mains.
Press [Off/Reset] on the LCP before programming parameters.
Ensure that the drive is fully wired and assembled when it is connected to AC mains, DC supply, or load sharing.
AJ363928382091en-000101 / 130R098312 | Danfoss A/S © 2021.04
Safety
VLT® Flow Drive FC 111
Design Guide

-
-
-
-
-
-
-
-
-
WARNING
DISCHARGE TIME
The drive contains DC-link capacitors, which can remain charged even when the drive is not powered. High voltage can be
present even when the warning indicator lights are off.
Failure to wait the specified time after power has been removed before performing service or repair work could result in death or
serious injury.
Stop the motor.
Disconnect AC mains, permanent magnet type motors, and remote DC-link supplies, including battery back-ups, UPS, and
DC-link connections to other drives.
Wait for the capacitors to discharge fully. The minimum waiting time is specified in the table Discharge time and is also visible
on the nameplate on the top of the drive.
Before performing any service or repair work, use an appropriate voltage measuring device to make sure that the capacitors
are fully discharged.
Table 3: Discharge Time
Voltage [V]
Power range [kW (hp)]
Minimum waiting time (minutes)
3x400
0.37–7.5 (0.5–10)
4
3x400
11–90 (15–125)
15
3x400
110–315 (150–450)
20
WARNING
LEAKAGE CURRENT HAZARD
Leakage currents exceed 3.5 mA. Failure to ground the drive properly can result in death or serious injury.
Ensure that the minimum size of the ground conductor complies with the local safety regulations for high touch current
equipment.
WARNING
EQUIPMENT HAZARD
Contact with rotating shafts and electrical equipment can result in death or serious injury.
Ensure that only trained and qualified 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 drive can result in serious injury when the drive is not properly closed.
Ensure that all safety covers are in place and securely fastened before applying power.
AJ363928382091en-000101 / 130R0983 | 13Danfoss A/S © 2021.04
Safety
VLT® Flow Drive FC 111
Design Guide

3 Product Overview
3.1 Advantages
3.1.1 Why Use a Drive for Controlling Fans and Pumps?
A drive takes advantage of the fact that centrifugal fans and pumps follow the laws of proportionality for such fans and pumps. For
further information, see 3.1.1.2 Example of Energy Savings.
3.1.1.1 The Clear Advantage - Energy Savings
The clear advantage of using a drive for controlling the speed of fans or pumps lies in the electricity savings.
When comparing with alternative control systems and technologies, a drive is the optimum energy control system for controlling
fan and pump systems.
e30ba780.11
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 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
e30ba781.11
ENERGY
CONSUMED
Illustration 2: Energy Savings with Drive Solution
AJ363928382091en-000101 / 130R098314 | Danfoss A/S © 2021.04
Product Overview
VLT® Flow Drive FC 111
Design Guide

When using a drive to reduce fan capacity to 60% - more than 50% energy savings may be obtained in typical applications.
3.1.1.2 Example of Energy Savings
As shown in the following illustration, the flow is controlled by changing the RPM. By reducing the speed by only 20% from the
rated speed, the flow is also reduced by 20%. This is because the flow is directly proportional to the RPM. The consumption of elec-
tricity, however, is reduced by 50%.
If the system in question only needs to be able to supply a flow that corresponds to 100% a few days in a year, while the average is
below 80% of the rated flow for the remainder of the year, the amount of energy saved is even more than 50%.
The following illustration describes the dependence of flow, pressure, and power consumption on RPM.
n
100%
50%
25%
12,5%
50% 100%
80%
80%
e75ha208.10
P o w er ~n
3
P r essur e ~n
2
Fl
o
w ~n
Illustration 3: Laws of Proportionally
Flow: Q1
Q2=n1 n2
Pressure: H1
H2=n1 n2
2
Power: P1
P2=n1 n2
3
Table 4: The Laws of Proportionality
Q = Flow
P = Power
Q1= Rated flow
P1 = Rated power
Q2= Reduced flow
P2= Reduced power
H = Pressure
n = Speed control
H1= Rated pressure
n1= Rated speed
H2= Reduced pressure
n2= Reduced speed
3.1.1.3 Comparison of Energy Savings
The Danfoss drive solution offers major savings compared with traditional energy saving solutions such as discharge damper solu-
tion and inlet guide vanes (IGV) solution. This is because the drive is able to control fan speed according to thermal load on the
system, and the drive has a built-in facility that enables the drive to function as a building management system, BMS.
The illustration in 3.1.1.2 Example of Energy Savings 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.
AJ363928382091en-000101 / 130R0983 | 15Danfoss A/S © 2021.04
Product Overview
VLT® Flow Drive FC 111
Design Guide

e30ba782.10
1
2
3
4
5
Illustration 4: The 3 Common Energy Saving Systems
1
Discharge damper
2
Less energy savings
3
Maximum energy savings
4
IGV
5
Costlier installation
e30ba779.12
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 5: Energy Savings
Discharge dampers reduce power consumption. Inlet guide vanes offer a 40% reduction, but are expensive to install. The Danfoss
drive 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.
AJ363928382091en-000101 / 130R098316 | Danfoss A/S © 2021.04
Product Overview
VLT® Flow Drive FC 111
Design Guide

3.1.1.4 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 sav-
ings of more than 50% at the given flow distribution over a year. The payback period depends on the price per kWh and the price of
drive. 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 [m3/h] 400 Q
e75ha210.11
Illustration 6: Flow Distribution over 1 Year
e75ha209.11
60
50
40
30
20
10
H
s
0
100
200 300 400
(m w g)
B
C
A
750r pm
1050r pm
1350r pm
1650r pm
0
10
20
30
(kW
)
40
50
60
200
100
300 ( m
3
/h )
( m
3
/h )
400
750r
pm
1050r pm
1350r pm
1650r pm
P
shaf
t
C
1
B
1
A
1
Illustration 7: Energy
Table 5: Result
m3/h
Distribution
Valve regulation
Drive control
%
Hours
Power
Consumption
Power
Consumption
A1- B1
kWh
A1- C1
kWh
AJ363928382091en-000101 / 130R0983 | 17Danfoss A/S © 2021.04
Product Overview
VLT® Flow Drive FC 111
Design Guide

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
Σ
100
8760
–
275.064
–
26.801
3.1.1.5 Better Control
If a drive is used for controlling the flow or pressure of a system, improved control is obtained.
A drive can vary the speed of the fan or pump, obtaining variable control of flow and pressure. Furthermore, a drive can quickly
adapt the speed of the fan or pump to new flow or pressure conditions in the system.
Simple control of process (flow, level, or pressure) utilizing the built-in PI control.
3.1.1.6 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 tradi-
tional systems, a star/delta starter or soft starter is widely used. Such motor starters are not required if a drive is used.
As shown in the following illustration, a drive 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
e75ha227.10
Illustration 8: Start-up Current
1
VLT® Flow Drive FC 111
2
Star/delta starter
3
Soft starter
4
Start directly on mains
3.1.1.7 Using a Drive Saves Money
The example in 3.1.1.8 Traditional Fan System without a Drive and 3.1.1.9 Fan System Controlled by Drives shows that a drive repla-
ces other equipment. It is possible to calculate the cost of installing the 2 different 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 Additional Resources to calculate the cost savings that can be ach-
ieved by using a drive.
AJ363928382091en-000101 / 130R098318 | Danfoss A/S © 2021.04
Product Overview
VLT® Flow Drive FC 111
Design Guide

3.1.1.8 Traditional Fan System without a Drive
M
- +
M
M
x6 x6
x6
e75ha205.12
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
Illustration 9: Traditional Fan System without a Drive
D.D.C.
Direct digital control
E.M.S.
Energy management system
V.A.V.
Variable air volume
Sensor
P
Pressure
Sensor
T
Temperature
AJ363928382091en-000101 / 130R0983 | 19Danfoss A/S © 2021.04
Product Overview
VLT® Flow Drive FC 111
Design Guide

3.1.1.9 Fan System Controlled by Drives
e75ha206.11
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
MPT
VLT
x3 x3
x3
Illustration 10: Fan System Controlled by Drives
D.D.C.
Direct digital control
E.M.S.
Energy management system
V.A.V.
Variable air volume
Sensor
P
Pressure
Sensor
T
Temperature
3.1.2 Application Examples
The following sections give typical examples of applications.
3.1.2.1 Variable Air Volume
VAV or variable air volume systems, control both the ventilation and temperature to satisfy the requirements of a building. Central
VAV systems are considered to be the most energy efficient method to air condition buildings. By designing central systems instead
of distributed systems, a greater efficiency can be obtained.
The efficiency comes from utilizing larger fans and larger chillers which have much higher efficiencies than small motors and distrib-
uted air-cooled chillers. Savings are also seen from the decreased maintenance requirements.
The VLT Solution
While dampers and IGVs work to maintain a constant pressure in the ductwork, a drive solution saves much more energy and re-
duces the complexity of the installation. Instead of creating an artificial pressure drop or causing a decrease in fan efficiency, the
drive decreases the speed of the fan to provide the flow and pressure required by the system.
Centrifugal devices such as fans behave according to the centrifugal laws. This means that the fans decrease the pressure and flow
they produce as their speed is reduced. Their power consumption is thereby significantly reduced. The PI controller of the drive can
be used to eliminate the need for additional controllers.
AJ363928382091en-000101 / 130R098320 | Danfoss A/S © 2021.04
Product Overview
VLT® Flow Drive FC 111
Design Guide