Siemens SIRIUS 3RW44 User manual

Manual
3RW44
Soft Starters
Edition
Industrial Controls
siemens.com/industrial-controls
03/2017

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Industrial Controls
Soft starters and solid-state
switching devices
3RW44 soft starters
Manual
03/2017
NEB535219502000/RS
-AB/008
Important notes
1
Introduction
2
Configuration instructions
3
Installation, connection and
feeder configuration
4
Display, controls and device
interfaces
5
Commissioning
6
Device functions
7
Diagnostics and messages
8
PROFIBUS DP
communication module
9
Typical circuit diagrams
10
General technical data
11
Appendix
A

Siemens AG
Division Digital
Factory
Postfach 48 48
90026 NÜRNBERG
GERMANY
3ZX1012-0RW44-1AC1
Ⓟ
03/2017 Subject to change
Copyright © Siemens AG 2005.
All rights reserved
Legal information
Warning notice system
This manual contains notices you have to observe in order to ensure your personal safety, as well as to prevent
damage to property. The notices referring to your personal safety are highlighted in the manual by a safety alert
symbol, notices referring only to property damage have no safety alert symbol. These notices shown below are
graded according to the degree of danger.
DANGER
indicates that death or severe personal injury will result if proper precautions are not taken.
WARNING
indicates that death or severe personal injury may result if proper precautions are not taken.
CAUTION
indicates that minor personal injury can result if proper precautions are not taken.
NOTICE
indicates that property damage can result if proper precautions are not taken.
If more than one degree of danger is present, the warning notice representing the highest degree of danger will
be used. A notice warning of injury to persons with a safety alert symbol may also include a warning relating to
property damage.
Qualified Personnel
The product/system described in this documentation may be operated only by
personnel qualified
for the specific
task in accordance with the relevant documentation, in particular its warning notices and safety instructions.
Qualified personnel are those who, based on their training and experience, are capable of identifying risks and
avoiding potential hazards when working with these products/systems.
Proper use of Siemens products
Note the following:
WARNING
Siemens products may only be used for the applications described in the catalog and in the relevant technical
documentation. If products and components from other manufacturers are used, these must be recommended
or approved by Siemens. Proper transport, storage, installation, assembly, commissioning, operation and
maintenance are required to ensure that the products operate safely and without any problems. The permissible
ambient conditions must be complied with. The information in the relevant documentation must be observed.
Trademarks
All names identified by ® are registered trademarks of Siemens AG. The remaining trademarks in this publication
may be trademarks whose use by third parties for their own purposes could violate the rights of the owner.
Disclaimer of Liability
We have reviewed the contents of this publication to ensure consistency with the hardware and software
described. Since variance cannot be precluded entirely, we cannot guarantee full consistency. However, the
information in this publication is reviewed regularly and any necessary corrections are included in subsequent
editions.

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4Manual, 03/2017, NEB535219502000/RS-AB/008
Table of contents
1 Important notes.......................................................................................................................................... 9
1.1 Security information ............................................................................................................... 11
2 Introduction.............................................................................................................................................. 12
2.1 Basic physical principles of the three-phase asynchronous motor and operating
principle of the soft starter...................................................................................................... 12
2.1.1 Three-phase asynchronous motor......................................................................................... 12
2.1.2 Principle of operation of the 3RW44 electronic soft starter ................................................... 14
2.2 Application and use................................................................................................................ 17
2.3 Marginal conditions for storage and operation....................................................................... 19
3 Configuration instructions ........................................................................................................................ 20
3.1 Configuration.......................................................................................................................... 20
3.1.1 RS 232 serial PC interface and Soft Starter ES parameterizing and operating software...... 20
3.1.2 Simulation Tool for Soft Starters (STS) ................................................................................. 20
3.2 Startup class .......................................................................................................................... 21
3.2.1 Application examples for normal starting (CLASS 10)........................................................... 22
3.2.2 Application examples for heavy starting (CLASS 20)............................................................ 23
3.2.3 Application examples for very heavy starting (CLASS 30).................................................... 24
3.3 ON time and switching frequency .......................................................................................... 25
3.4 Installation altitude and ambient temperature........................................................................ 26
3.5 Factory settings...................................................................................................................... 27
3.6 Article number system for SIRIUS 3RW44 soft starters ........................................................ 28
4 Installation, connection and feeder configuration..................................................................................... 29
4.1 Installing the soft starter......................................................................................................... 29
4.1.1 Unpacking .............................................................................................................................. 29
4.1.2 Mounting position................................................................................................................... 29
4.1.3 Installation requirements........................................................................................................ 30
4.1.4 Mounting dimensions and clearances ................................................................................... 31
4.2 Design of the feeder............................................................................................................... 32
4.2.1 General information ............................................................................................................... 32
4.2.2 Soft starters in standard circuits............................................................................................. 33
4.2.3 Soft starters in inside-delta circuits ........................................................................................ 35
4.2.4 Soft starter with contactor disconnector (main contactor) ..................................................... 38
4.3 Protection of the soft starter against short-circuits (type of assignment 2)............................ 40
4.4 Capacitors for improving the power factor ............................................................................. 41
4.5 Generator operation with three-phase asynchronous motor ................................................. 42
4.6 Electrical connection .............................................................................................................. 42
4.6.1 Control and auxiliary circuit connection ................................................................................. 42

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Manual, 03/2017, NEB535219502000/RS-AB/008 5
4.6.2 Main circuit connection ...........................................................................................................42
4.6.3 Conductor cross-sections .......................................................................................................44
5 Display, controls and device interfaces.................................................................................................... 46
5.1 Display and controls................................................................................................................46
5.2 Device interfaces ....................................................................................................................47
5.2.1 Local device interface .............................................................................................................47
5.2.2 PROFIBUS/PROFINET interface (optional) ...........................................................................47
5.3 External display and control module (optional).......................................................................47
6 Commissioning ........................................................................................................................................ 48
6.1 Menu structure, navigation, changing parameters .................................................................48
6.1.1 Menu structure and navigation ...............................................................................................48
6.1.2 Changing parameters: for example motor data......................................................................49
6.2 Switching on for the first time..................................................................................................50
6.2.1 Recommended procedure for commissioning 3RW44...........................................................50
6.2.2 Quick start menu, when switching on for the first time ...........................................................51
6.2.3 Problems that can occur .........................................................................................................53
6.2.4 Quick Start menu ....................................................................................................................56
6.3 User-specific commissioning ..................................................................................................58
6.3.1 Settings main menu item ........................................................................................................59
6.4 Making settings in the selected parameter set .......................................................................60
6.4.1 Selecting the parameter set....................................................................................................60
6.4.2 Entering the motor data ..........................................................................................................61
6.4.3 Specifying the startup mode ...................................................................................................63
6.4.4 Specifying the coasting method..............................................................................................75
6.4.5 Setting slow speed parameters ..............................................................................................86
6.4.6 Specifying current limit values ................................................................................................88
6.4.7 Parameterizing the inputs .......................................................................................................89
6.4.8 Parameterizing the outputs.....................................................................................................92
6.4.9 Selecting motor protection settings.........................................................................................94
6.4.10 Selecting display settings .......................................................................................................97
6.4.11 Specifying the behavior of the protective functions ................................................................98
6.4.12 Specifying the names on the device display.........................................................................100
6.4.13 Activating the fieldbus interface (PROFIBUS DP/PROFINET IO)........................................101
6.4.14 Saving options ......................................................................................................................102
6.5 Other device functions ..........................................................................................................107
6.5.1 Measured values display ......................................................................................................107
6.5.2 Status display........................................................................................................................109
6.5.3 Motor control (assigning control priority)...............................................................................110
6.5.4 Statistics................................................................................................................................112
6.5.5 Safety (specifying the user level, parameterization protection)............................................118
7 Device functions .................................................................................................................................... 119
7.1 Various parameter sets.........................................................................................................119
7.1.1 Various parameter sets.........................................................................................................119
7.2 Startup modes.......................................................................................................................119
7.2.1 Voltage ramp.........................................................................................................................119
7.2.2 Torque control.......................................................................................................................121

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7.2.3 Breakaway pulse in combination with the voltage ramp or torque control startup mode .... 124
7.2.4 Current limitation in combination with the voltage ramp or torque control startup mode..... 125
7.2.5 Direct startup mode.............................................................................................................. 127
7.2.6 Motor heating startup mode................................................................................................. 127
7.3 Coasting methods ................................................................................................................ 128
7.3.1 Coasting down ..................................................................................................................... 129
7.3.2 Torque control and pump stop............................................................................................. 129
7.3.3 DC braking/combined braking.............................................................................................. 131
7.4 Slow speed function............................................................................................................. 134
7.5 Current limits for load monitoring......................................................................................... 135
7.6 Motor protection functions.................................................................................................... 136
7.7 Intrinsic device protection .................................................................................................... 139
7.7.1 Intrinsic device protection .................................................................................................... 139
8 Diagnostics and messages.................................................................................................................... 140
8.1 Diagnostics and messages.................................................................................................. 140
8.1.1 Status messages ................................................................................................................. 140
8.1.2 Warnings and group faults................................................................................................... 141
8.1.3 Device fault .......................................................................................................................... 147
9 PROFIBUS DP communication module................................................................................................. 149
9.1 Introduction .......................................................................................................................... 149
9.1.1 Definitions ............................................................................................................................ 151
9.2 Data transfer ........................................................................................................................ 152
9.2.1 Options for data transfer ...................................................................................................... 152
9.2.2 Communication principle...................................................................................................... 153
9.3 Installing the PROFIBUS DP communication module ......................................................... 153
9.3.1 Inserting the PROFIBUS DP communication module (fieldbus interface)........................... 154
9.4 Activating the PROFIBUS DP communication module (fieldbus interface) and setting
the station address............................................................................................................... 156
9.4.1 Introduction .......................................................................................................................... 156
9.4.2 Activating the PROFIBUS DP communication module via the display, setting the
station address and saving the settings............................................................................... 157
9.4.3 Activating the PROFIBUS DP communication module (fieldbus interface) and setting
the station address via the device interface using the "Soft Starter ES Premium" or the
"Soft Starter ES Smart + SP1" software .............................................................................. 160
9.5 Configuring soft starters....................................................................................................... 162
9.5.1 Introduction .......................................................................................................................... 162
9.5.2 Configuring with the GSD file............................................................................................... 162
9.5.3 Configuring with the Soft Starter ES Professional software ................................................ 163
9.5.4 Diagnostics package............................................................................................................ 163
9.5.5 Soft Starter ES parameterization software .......................................................................... 163
9.6 PROFIBUS DP commissioning using the GSD file in STEP 7 (example) ........................... 164
9.6.1 Introduction .......................................................................................................................... 164
9.6.2 Configuration using the Device Master Data (GSD) in STEP 7........................................... 165
9.6.3 Integration into the user program......................................................................................... 168
9.6.4 Switching on......................................................................................................................... 168

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9.6.5 Flow diagram: PROFIBUS DP starting the soft starter.........................................................169
9.7 Process data and process images........................................................................................170
9.8 Diagnosis via LED display ....................................................................................................171
9.9 Diagnosis with STEP 7 .........................................................................................................172
9.9.1 Reading out the diagnostic data ...........................................................................................172
9.9.2 Options for reading diagnostic data......................................................................................172
9.9.3 Structure of the slave diagnostics.........................................................................................173
9.9.4 Station status 1 to 3 ..............................................................................................................174
9.9.5 Master PROFIBUS address..................................................................................................176
9.9.6 Manufacturer ID ....................................................................................................................176
9.9.7 ID-related diagnostics ...........................................................................................................176
9.9.8 Module status........................................................................................................................177
9.9.9 Channel-related diagnostics .................................................................................................178
9.10 Data formats and data sets...................................................................................................180
9.10.1 Properties..............................................................................................................................180
9.11 Identification number (ID No.), error codes ..........................................................................184
9.11.1 Identification number (ID No.)...............................................................................................184
9.11.2 Error codes for negative data set acknowledgement ...........................................................184
9.12 Data sets (BS).......................................................................................................................186
9.12.1 Data set 68 - Reading/writing the process image of the outputs..........................................187
9.12.2 Data set 69 - Reading the process image of the inputs........................................................188
9.12.3 Data set 72 - Logbook - Reading device errors....................................................................189
9.12.4 Data set 73 - Logbook – Reading the trips ...........................................................................190
9.12.5 Data set 75 - Logbook - Reading events ..............................................................................192
9.12.6 Data set 81 - Reading the basic settings of data set 131.....................................................194
9.12.7 Data set 82 - Reading the basic settings of data set 132.....................................................194
9.12.8 Data set 83 - Reading the basic settings of data set 133.....................................................194
9.12.9 Data set 92 - Reading device diagnostics ............................................................................194
9.12.10 Data set 93 - Writing a command .........................................................................................201
9.12.11 Data set 94 - Reading measured values ..............................................................................202
9.12.12 Data set 95 - Reading statistical data...................................................................................203
9.12.13 Data set 96 - Reading the maximum pointer ........................................................................204
9.12.14 Data set 100 - Reading the device identification ..................................................................206
9.12.15 Data sets 131, 141, 151 - Technology parameters 2: Reading/writing sets 1, 2, 3..............207
9.12.16 Data sets 132, 142, 152 - Technology parameters 3:
Reading/writing sets 1, 2, 3 ..................................................................................................212
9.12.17 Data set 133 - Technology parameters 4: HMI module........................................................213
9.12.18 Data set 160 - Reading/writing communication parameters.................................................214
9.12.19 Data set 165 - Reading/writing comments............................................................................215
10 Typical circuit diagrams ......................................................................................................................... 216
10.1 Connection examples for main and control circuits..............................................................216
10.1.1 3RW44 in a standard circuit with control via keys ................................................................216
10.1.2 3RW44 in a standard circuit with line contactor and control via PLC...................................218
10.1.3 3RW44 in a standard circuit and DC braking stopping function for device types 3RW44
22 to 3RW44 25....................................................................................................................219
10.1.4 3RW44 in a standard circuit and DC braking stopping function for device types 3RW44
26 to 3RW44 66....................................................................................................................220
10.1.5 3RW44 in an inside-delta circuit ...........................................................................................221

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10.1.6 3RW44 in a standard circuit and control like a contactor .................................................... 223
10.1.7 3RW44 in a standard circuit with soft start/stop and additional slow speed function in
both directions of rotation with one parameter set............................................................... 224
10.1.8 Control via @PROFIBUS with switchover to manual local operation (e.g. on the
control cabinet)..................................................................................................................... 226
10.1.9 3RW44 in a standard circuit and reversing operation via main contactors with one
parameter set without soft stopping..................................................................................... 227
10.1.10 Reversing operation with soft stopping................................................................................ 229
10.1.11 Soft starter for pole-changing motor with separate windings and 2 parameter sets ........... 230
10.1.12 Soft starter for Dahlander motors with 2 parameter sets..................................................... 232
10.1.13 Parallel starting of 3 motors ................................................................................................. 233
10.1.14 Soft starter for serial starting with 3 parameter sets ............................................................ 235
10.1.15 Soft starter for serial starting with 3 parameter sets (deactivate soft stop and 3RW44
motor protection).................................................................................................................. 237
10.1.16 Soft starter for activation of a motor with a magnetic fixing brake....................................... 238
10.1.17 Safe disconnection according to IEC 62061 (SIL) and/or ISO 13849-1 (PL) ...................... 239
10.1.18 Soft starter with direct-on-line starting (DOL) as emergency start....................................... 240
10.1.19 Soft starter with star-delta starter as emergency start (3RW44 in a standard circuit)......... 241
10.1.20 Soft starter and frequency converter on one motor ............................................................. 242
11 General technical data........................................................................................................................... 243
11.1 Menu structure ..................................................................................................................... 243
11.2 Transport and storage conditions ........................................................................................ 252
11.3 Technical data...................................................................................................................... 253
11.3.1 Selection and ordering data................................................................................................. 253
11.3.2 Technical data of the power unit.......................................................................................... 259
11.3.3 Technical data of the control section ................................................................................... 264
11.3.4 Conductor cross-sections .................................................................................................... 268
11.3.5 Electromagnetic compatibility .............................................................................................. 269
11.3.6 Feeder component layout (standard circuit) ........................................................................ 270
11.3.7 Feeder component layout (inside-delta circuit).................................................................... 275
11.3.8 Accessories.......................................................................................................................... 277
11.3.9 Spare parts........................................................................................................................... 280
11.4 Tripping characteristics ........................................................................................................ 281
11.4.1 Motor protection tripping characteristics: 3RW44 with symmetry........................................ 281
11.4.2 Motor protection tripping characteristics: 3RW44 with asymmetry...................................... 282
11.5 Dimension drawings............................................................................................................. 283
11.5.1 Dimension drawings............................................................................................................. 283
A Appendix................................................................................................................................................ 288
Index...................................................................................................................................................... 291

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Manual, 03/2017, NEB535219502000/RS-AB/008 9
Important notes
1
Purpose of this manual
This manual contains fundamental information and practical tips for using SIRIUS 3RW44
soft starters. The SIRIUS 3RW44 soft starter is an electronic motor control device that
enables optimized starting and stopping of three-phase asynchronous motors.
This manual describes all the functions of the SIRIUS 3RW44 soft starter.
Target group
This manual is intended for any user involved in
●Commissioning
●Servicing and maintenance
●Planning and configuring systems
Basic knowledge required
A general knowledge of the field of electrical engineering is required to understand this
manual.
Validity
This manual is valid for SIRIUS 3RW44 soft starters. It contains a description of the
components that are valid at the time of publication of this manual. SIEMENS reserves the
right to include updated information about new components or new versions of components
in a Product Information.
Definitions
Where the short form 3RW44 is used in the text, it refers to the SIRIUS 3RW44 soft starter.
Standards and approvals
The SIRIUS 3RW44 soft starter is based on IEC/EN 60947-4-2.

Important notes
1.1 Security information
3RW44 soft starters
10 Manual, 03/2017, NEB535219502000/RS-AB/008
Disclaimer of liability
The manufacturer of the system or machine is responsible for ensuring the correct overall
functioning. SIEMENS AG, its regional offices, and associated companies (hereinafter
referred to as "SIEMENS") cannot guarantee all the properties of a system or machine not
designed by SIEMENS.
Nor can Siemens assume liability for recommendations given or implied by the following
description. No new guarantee, warranty, or liability claims beyond the scope of the
SIEMENS general terms and conditions of supply are to be derived or inferred from the
following description.
Access aids
To facilitate and speed up access to special information, the manual contains the following
aids:
●At the beginning of the manual you will find a table of contents.
●The individual chapters contain subheadings that provide an overview of the contents of
the section.
●At the end of the manual, there is an extensive index to enable you to quickly access the
required information.
Up-to-the-minute information at all times
Your regional contacts for communication-capable low-voltage controls will be pleased to
assist you with any queries you have regarding the motor starters. A list of contacts and the
latest version of the manual are available on the Internet
(http://www.siemens.com/softstarter).
For all technical queries, please contact:
Technical Assistance:
Telephone: [phone] (8°° - 17°° CET) Fax: [phone]
E-mail (mailto:technical-assist[email protected])
Internet (https://support.industry.siemens.com/my/ww/en/requests)
Technical Support:
Telephone: [phone]
Correction sheet
A correction sheet is included at the end of this manual. Please use it to record your
suggestions for improvements, additions, and corrections, and return the sheet to us. This
will help us to improve the next edition of the manual.

Important notes
1.1 Security information
3RW44 soft starters
Manual, 03/2017, NEB535219502000/RS-AB/008 11
1.1
Security information
Siemens provides products and solutions with industrial security functions that support the
secure operation of plants, systems, machines, and networks.
In order to protect plants, systems, machines and networks against cyber threats, it is
necessary to implement – and continuously maintain – a holistic, state-of-the-art industrial
security concept. Siemens’ products and solutions only form one element of such a concept.
Customer is responsible to prevent unauthorized access to its plants, systems, machines
and networks. Systems, machines and components should only be connected to the
enterprise network or the internet if and to the extent necessary and with appropriate security
measures (e.g. use of firewalls and network segmentation) in place.
Additionally, Siemens’ guidance on appropriate security measures should be taken into
account. For more information about industrial security, please visit:
http://www.siemens.com/industrialsecurity.
Siemens’ products and solutions undergo continuous development to make them more
secure. Siemens strongly recommends to apply product updates as soon as available and to
always use the latest product versions. Use of product versions that are no longer supported,
and failure to apply latest updates may increase customer’s exposure to cyber threats.
To stay informed about product updates, subscribe to the Siemens Industrial Security RSS
Feed under
http://www.siemens.com/industrialsecurity.

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12 Manual, 03/2017, NEB535219502000/RS-AB/008
Introduction
2
2.1
Basic physical principles of the three-phase asynchronous motor
and operating principle of the soft starter
2.1.1
Three-phase asynchronous motor
Application areas of the three-phase asynchronous motor
Three-phase asynchronous motors are used in a wide range of applications in commerce,
industry and trade owing to their simple, rugged design and their low-maintenance operation.
Problem
If a three-phase asynchronous motor is started directly, its typical current and torque
characteristics can cause disturbances in the supply system and the load machine.
Starting current
Three-phase asynchronous motors have a high direct starting current I (startup). Depending on
the motor version it can amount to between three times and fifteen times the rated
operational current. Seven to eight times the rated motor current can be taken as a typical
value.

Introduction
2.1 Basic physical principles of the three-phase asynchronous motor and operating principle of the soft starter
3RW44 soft starters
Manual, 03/2017, NEB535219502000/RS-AB/008 13
Disadvantage
This results in the following disadvantage:
●Higher load on the electrical supply system. This means that the supply system must be
dimensioned for this higher output during the motor startup.
Figure 2-1 Typical starting current characteristic of a three-phase asynchronous motor
Locked-rotor torque
The starting torque and the breakdown torque can usually be assumed to be between two
and four times the rated torque. For the load machine this means that the starting and
acceleration forces in relation to rated operation give rise to a higher mechanical load on the
machine and the conveyed material.

Introduction
2.1 Basic physical principles of the three-phase asynchronous motor and operating principle of the soft starter
3RW44 soft starters
14 Manual, 03/2017, NEB535219502000/RS-AB/008
Disadvantages
This results in the following disadvantages
●A higher load is placed on the machine's mechanical components
●Higher costs for replacing worn parts and maintaining the application
Figure 2-2 Typical starting torque characteristic of a three-phase asynchronous motor
Solution
The SIRIUS 3RW44 electronic soft starter allows the current and torque characteristics
during startup to be optimally adapted to the requirements of each application.
2.1.2
Principle of operation of the 3RW44 electronic soft starter
The 3RW44 soft starter features two antiparallel thyristors in each of the phases. There is
one thyristor for the positive and one thyristor for the negative half-wave.
The rms value of the motor voltage is increased (from an adjustable starting voltage or
starting torque) to the rated motor voltage within a definable starting time by means of the
leading-edge phase. This is achieved using various control methods.
The motor current changes in proportion to the voltage applied to the motor. The starting
current is thus reduced by the factor of the voltage applied to the motor.
The torque changes in squared proportion to the voltage applied to the motor. The starting
torque is thus reduced in squared proportion to the voltage applied to the motor.

Introduction
2.1 Basic physical principles of the three-phase asynchronous motor and operating principle of the soft starter
3RW44 soft starters
Manual, 03/2017, NEB535219502000/RS-AB/008 15
Example
SIEMENS 1LG4253AA motor (55 kW)
Rated data at 400
V
P
e
:
55 kW
I
e
:
100 A
I
direct starting
:
approx. 700 A
M
e:
355
Nm
Example:
n
e
:
1480 rpm
M
direct starting
:
approx. 700 Nm
Set starting voltage:
50 % (½ of line voltage)
=> Istarting ½ of direct-on-line starting switch-on current (approx. 350 A)
=> M
starting
¼ of direct-on-line starting torque (approx. 175 Nm)
The diagrams below show the starting current and torque characteristics for a three-phase
asynchronous motor in combination with a soft starter:
Figure 2-3 Reduced current characteristic of a three-phase asynchronous motor during startup with
a SIRIUS 3RW44 soft starter

Introduction
2.1 Basic physical principles of the three-phase asynchronous motor and operating principle of the soft starter
3RW44 soft starters
16 Manual, 03/2017, NEB535219502000/RS-AB/008
Figure 2-4 Reduced torque characteristic of a three-phase asynchronous motor during startup with
a SIRIUS 3RW44 soft starter
Startup
This means that, since the motor voltage is controlled by the electronic soft starter during the
startup process, the consumed starting current and the starting torque generated in the
motor are also controlled.
The same principle is applied during the stopping process. This way the torque generated in
the motor is slowly reduced, thus enabling a smooth ramp-down of the application.
The frequency remains constant during this process and corresponds to the line frequency,
in contrast to frequency-controlled startup and stopping of a frequency converter.
Once the motor has started up correctly, the thyristors are fully utilized, meaning that the
complete line voltage is applied to the motor terminals. As the motor voltage does not have
to be controlled during operation, the thyristors are bridged by integrated bypass contacts.
This minimizes the waste heat generated during continuous operation (which is caused by
the thyristor's power loss). Therefore the area around the switching devices heats up less.

Introduction
2.2 Application and use
3RW44 soft starters
Manual, 03/2017, NEB535219502000/RS-AB/008 17
The diagram below shows the method of operation of the 3RW44 soft starter:
Figure 2-5 Phase angle control and schematic diagram of a soft starter with internal bypass contacts
2.2
Application and use
Applications and selection criteria
3RW44 soft starters can be used as an alternative to star-delta (wye-delta) starters and
frequency converters.
Their main benefits are their ability to perform soft starting, soft stops, and uninterrupted
changeover without current peaks that put a strain on the system, as well as their compact
dimensions.
Many drives that could previously only be operated with frequency converters can be
changed over to soft starter operation using the 3RW44 soft starter, provided no speed
control, no particularly high starting torque, or startup with close to rated current, is required.

Introduction
2.2 Application and use
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Applications
Typical applications include:
●Conveyor belts
●Roller conveyors
●Compressor
●Ventilators, fans
●Pump
●Hydraulic pumps
●Stirrers
●Centrifuges
●Milling machines
●Mills
●Crushers
●Circular saws/bandsaws
●...
Advantages
Conveyor belts, conveyor systems:
●Smooth starting
●Smooth braking
Rotary pumps, piston pumps:
●No pressure surges
●Increased service life of the pipe system
Agitators, mixers:
●Reduced starting current
Fans:
●Reduced stress on gearbox and V belt

Introduction
2.3 Marginal conditions for storage and operation
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Manual, 03/2017, NEB535219502000/RS-AB/008 19
2.3
Marginal conditions for storage and operation
Permissible ambient temperature for
- Storage
-25 °C ... +80 °C
- Operation 0 °C ... +60 °C, from 40 °C with derating
(refer to chapter Technical data (Page 253))
Permissible relative humidity
10 ... 95 %
Permissible maximum installation altitude
5000 m, from 1000 m with derating
NOTICE
Risk of property damage.
Make sure no liquids, dust, or conductive objects can get inside the soft starter.

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Configuration instructions
3
3.1
Configuration
The 3RW44 electronic soft starters are designed for normal starting. In case of heavy
starting or increased starting frequency, a larger unit may have to be selected.
For long starting times it is recommended to have a PTC sensor in the motor. This also
applies to soft stop, pump stop and DC braking coasting methods because, during the coast-
down time in these modes, an additional current loading applies in contrast to coasting
down.
The motor feeder between the soft starter and motor must not contain any capacitive
elements (such as compensation systems). Active filters must not be operated in
combination with soft starters.
All elements of the main circuit (such as fuses and switching devices) should be
dimensioned for direct-on-line starting, following the local short-circuit conditions, and must
be ordered separately.
The harmonic component load for starting currents must be taken into consideration for the
selection of motor starter protectors (selection of trip unit).
3.1.1
RS 232 serial PC interface and Soft Starter ES parameterizing and operating
software
The electronic 3RW44 soft starters have a PC interface for communicating with the Soft
Starter ES smart software and an operating and monitoring module (display).
3.1.2
Simulation Tool for Soft Starters (STS)
With this software, you can simulate and select all Siemens soft starters, taking into account
various parameters such as line conditions, motor and load data, and special application
requirements, etc.
The Simulation Tool for Soft Starters (STS) can be downloaded from the Internet
(https://support.industry.siemens.com/cs/ww/en/view/101494917).