Soft starters.

WEG has recently launched the SSW900 series of soft starters. These compact soft starters, which replace the current SSW06 soft starter series, are designed for industrial and commercial applications. As high-performance top-end devices with integrated PLC functionality, they provide fully programmable algorithms for regulating induction motors as well as fully flexible torque control.

The new series covers output currents from 10 A to 412 A in the wide voltage range of 220 to 575 V AC (three-phase) with four case sizes. Thanks to soft starting and integrated protection functions, the SSW900 ensures energy-efficient and reliable operation of electric motors. The device is suitable for a broad range of applications, including blowers and ventilation fans, axial, radial and centrifugal pumps, metering pumps, stirrers and mixers, conveyor belts, extruders, dryers and industrial ovens, turntables, and ball or hammer mills.

Johannes Schwenger, Head of Product Management Low Voltage and Medium Voltage Drive Systems Europe at WEG, comments: “The SSW900 series of soft starters expands our portfolio in an area which was previously not a focus of our activities in Europe. The new SSW900 devices are easy to use, and the integrated PLC allows the output torque to be adapted to the load and the start-up current to be kept as low as possible. Numerous protection functions are also integrated to ensure reliable operation of electric motors.”

The soft starter supports direct motor connection in wye or delta configuration, as well as wye/delta switching with six motor leads. This allows the three motor phases to be wired directly to the three thyristor pairs of the SSW900. As a result, the soft starter only has to provide 58% of the rated motor current (corresponding to the phase current), allowing a smaller device to be used for the same power level. The device has an integrated bypass contactor for longer service life, optimal space utilisation and lower heat dissipation (nearly zero) in the switchgear cabinet. Ease of use is further enhanced by a real-time clock as well as diagnostic and status query functions. Three different stop methods and a kick-start function expand the scope of potential applications.

The LCD display and a new user interface simplify operation and make programming changes quick and easy for users. Commissioning and programming are assisted by wizard functions. USB functionality integrated in the user interface enables configuration of the soft start parameters using the free Windows-based WPS software, as well as programming of the internal SoftPLC using the free WLP software.

The user interface language options include English, German, Portuguese and Spanish. Users can choose from Modbus RTU, Profibus DP, DeviceNet, Ethernet/IP, Modbus TCP and Profinet I/O industrial communication protocols for device connectivity.

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Profile for motor starters

CiA (CAN in Automation) has released the CiA 442 CANopen profile for IEC 61915-2 compatible motor starters. The IEC standard specifies a bus-independent profile for motor starters, soft starters, and motor management starters. The CiA profile is functional compatible and adds just the mapping to the CANopen application layer (CiA 301). In particular, it specifies the format of the commands and status information as well as the PDO parameters.

The motor (soft) starter continuously controls the three-phase motor’s voltage supply during the start-up phase. They limit the torque. This way, the motor is adjusted to the machine’s load behavior. Mechanical operating equipment is accelerated in a gentle manner.

The benefit of the bus-independent, international standardized profile is that the user saves its software investment, if suppliers or network technologies are changed. The finite state machine is standardized as well as the functional behavior. Of course, the mapping to messages depends on the used network. The CANopen profile pre-defines all PDOs as event-triggered. Synchronous transmission is optionally possible.

Intelligent softstarter

Automatic settings deliver correct starting current regardless of load

Carlo Gavazzi has launched the RSBS single phase, plug ‘n’ play Softstart motor controller that delivers a smooth start and long term reliability for single phase high pressure scroll compressors typically used in the growing heat pump market. 

The RSBS has been developed to reduce high inrush currents and associated effects to prolong compressor life.  The compact design features a self-adapting algorithm that will automatically react to changing load conditions to ensure that a wide range of compressors are started with the correct current and within the required ramp-up time of 600ms.

This self-adaptation feature eliminates light flickering and voltage disturbances, while reducing mechanical stresses on the compressor, and minimises the number of alarms during start-up, resulting in fewer service calls and reduced system downtime.  The RSBS features integrated protection against short-cycling, with an internal delay to ensure a maximum of ten starts per hour is observed.

To address the issue of weak power supplies in remote locations, the under voltage alarm is only active during bypass mode.  Other alarms such as Locked Rotor and End of Ramp protect the system during start up, leading to a reduction in system stoppage and service calls.

Alarm indication is provided through a red LED which signals the type of alarm via a user friendly flashing sequence.  The RSBS can also be supplied with an optional auxiliary alarm relay to interface additional alarm systems to the external panel.  Featuring compact dimensions of 137 x 84 x 60mm, the RSBS is easy to fit in any existing panel design via DIN rail or panel mount.

Smart soft starters optimise energy use

Carlo Gavazzi is introducing three new ranges of soft-starters designed to optimise energy consumption in industrial applications. The RSQK, RSXK and RSDR series’ provide soft-starting capability for three-phase motors up to 1050kW, with high-end models offering intelligent plug-and-play setup to ensure optimal starting profiles.

Automatic features such as auto end start/stop, soft stop smoothing auto pedestal are built into the RSQK and RSXK soft-starters. They continually adjust their settings to optimise operation, saving time and money in maintenance as well as commissioning.

RSQK series starters are rated for motor currents from 23 to 1800A at operating voltages 230 -460/400-575/500-690 VAC, whilst the RSXK is rated 5-1673A, 230-690VAC. Soft-starting/soft-stopping time is adjustable up to 255s, ensuring that even the toughest applications can be started and stopped in the correct manner.

Both RSQK and RSXK soft starters can control heavy duty loads (Trip Class 30) such as crushers. A user-friendly soft starter selection tool provides a quick and easy selection of the correct configuration for any particular application. In addition, they have pre-set starting and stopping parameters specifically for pump applications, which reduce water hammering by making start and stop actions as smooth as possible.

In addition, the RSQK provides an inductive load feature, which controls voltage across the transformer winding to ensure the transformer stays within current limits throughout the heating cycle.

For smaller motors, the new RSDR series offers power ratings up to 280kW. Maximum current ratings range from 55 to 500A. As well as over current and short-circuit protection, the RSDR has internal bypassing to reduce heat dissipation in tight control panels.

The RSDR soft starters provide ramp- up time setting capabilities starting from 0.5s, making them suitable for applications where start up time needs to be limited. Ramp- up and -down times can be set up to 30s, ensuring reliable soft-starting and stopping to deliver smoother start-up and shutdown of high inertia applications. Front-panel dimensions range from 135 x 140mm 203 x 165mm, providing space-saving solutions with high power capability.

Set up is simple through rotary controls on the RSDR front panel.  Two normally-open auxiliary relay contacts are provided for indication of top-of-ramp status and fault alarms.

As well as new applications where soft-starting is deployed inline to ensure lower inrush current, lower peak-demand energy costs and longer compressor lifetimes, these three new series’ offer easy replacement of star-delta starters. Their six-wire connection option means that there is no need to change the wiring configuration, providing a lower cost alternative with reduced maintenance requirements, lower down-times and less stress on auxiliary components.

All the new devices are IP20 protected against dust and moisture ingress up to 55kW, operate over the 0-40°C temperature range and carry UL certification and CE markings.