Siemens 3RW52 & 3RW55 Softstarts

Welcome to the world of Siemens 3RW52/55 Softstarts, today's solution to excessive input current demand and component stress.

Siemens 3RW52 and 3RW55 Softstarts

Siemens 3RW52 Softstarts

For applications that currently use star-delta starters, the 3RW52 is the ideal choice. As a general purpose soft start, it can be used on any drive and is a true all-rounder.

Sirius 3RW52 are available for drives from 5.5 to 560kW (at 400 V) optimal motor start is achieved by controlling all three phases. The general purpose drive offers electrical robustness and is the ideal solution for standard starting applications.

Communication to plant networks can be ensured using the PROFINET, PROFIBUS or Modbus bus plug-in communication modules thus ensuring your soft start is industry 4.0 ready. Sirius 3RW52 general performance soft starters are available with either an analogue output or thermistor motor protection. Parameterisation of the soft start can be achieved over the rotary setting elements, an optional HMI module is also available.

Hybrid switching technology ensures that the 3RW52 offers efficient long-term switching for energy saving possibilities.

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Siemens 3RW55 Softstarts

The 3RW55 is an intelligent soft starter that offers maximum functionality, it masters all difficult start-up and stopping processes. Sirius 3RW55 can confidently handle any difficult starting and stopping operations due to the inbuilt smart functions:

  • Pump Cleaning
  • Pump Stop
  • Automatic Parameterization
  • Condition Monitoring

The functions are integrated to support end users with the smooth running of their plant. Sirius 3RW55 are available for drives from 5.5 to 1200kW (at 400 V) and controls all three phases for optimal motor starting. Various communication options are available for integrating the soft starts into the plant network, ensuring 3RW55 are ready for industry 4.0. The plug-in communication modules are available in PROFINET, PROFIBUS and Modbus bus protocols.

With an integrated operator panel and display and electrical robustness, as well as offering configuration in the TIA portal via the Soft Starter ES software the 3RW55 is the perfect choice when a high-performance soft start is required.

With their modern hybrid switching technology, the SIRIUS 3RW55 soft starters offer efficient switching for long-term, energy-saving use.

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Most industrial applications run on core machinery such as compressors, pumps, blowers and conveyor belts. These all require a large voltage input when they start up, and can draw up to six times their normal operating current for the start-up process. This can put undue stress on motor components and cause problems for your entire electrical system, especially when dealing with larger motors. This is where the Softstart comes in.

Using a unique hybrid combination of semiconductors and mechanical switching systems, Siemens 3RW52/55 Softstarts allow the motor's input current to increase gradually until it reaches its stable operational state, thus reducing both start-up current demand and motor torque. They also incorporate several intelligent functions that will enhance the performance of almost any application, including integrated braking, automatic parameterisation and condition monitoring.

Condition Monitoring

Sample Use Case: Compressors

Condition Monitoring means that the active motor power and electrical data of the Siemens 3RW52/55 Softstart is under constant evaluation, offering you a new level of operational transparency. A continual supply of measured data allows you to see immediately if, for example, a mechanical component is exhibiting signs of wear or impending damage; if your compressor's lubricant is wearing thin, or if a pump is about to run dry.

Automatic Parameterisation

Sample Use Case: Conveyor Belts

When you soft start your conveyor belt, it must adjust itself continually to changes in conditions resulting from the altered starting weights. The Siemens 3RW52/55 uses its Automatic Parameterisation function to analyse and identify the load conditions. It can then set the appropriate values to start the belt at the optimal parameters for its load.

Integrated Brake Functions

Sample Use Case: Sawmill, Panel Cutter

Industrial sawing and cutting plants use slow, heavy blades that require soft starting in order to protect their mechanical and electrical systems. It must also be possible to effect a rapid stop, for example, in an emergency or when blades need changing. The Siemens 3RW55's Integrated Brake Function automatically supports reverse and DC braking, and also controls system components such as reversing contactors and braking contacts.

Pump Cleaning

Sample Use Case: Waste Water

All sorts of applications use pumps to convey liquids. In waste water treatment, particulates and dirt carried in the waste water can get deposited on the wheels of pump blades, which will reduce the pump's capacity and overall productivity. The Siemens 3RW52/55's Pump Cleaning function is designed to detect dirt and deposits with its integrated measurement technology. As soon as these exceed the defined limit values, a change is made in the pump’s rotational direction.

Pump Stop

Sample Use Case: Water Supply

Shutting down a pumping station is a challenge when the pumps are controlling a large volume of water, for example, in the municipal water supply. An unscheduled or abrupt stop can lead to 'water hammering' in pipes, valves, couplings and seals, if the kinetic energy of the accumulated water is allowed to build up. The Siemens 3RW52/55's Pump Stop function provides a controlled soft stop, so that the threat of water hammering damage is prevented.

Electrical Robustness

Sample Use Case: Fans

Industrial scale air conditioning systems generally use very big and heavy fans, that often take a long time to start up. This sometimes results in a dip in the supply voltage, which can cause knock-on problems in the electrical network. The Siemens 3RW52/55 Softstarts incorporate a wide voltage range, from 110 to 250V AC, so that even if the voltage dips occasionally, the Softstart unit, the motor, the network and your given application are still guaranteed to operate.