Soft starters score with simple setup

An ABB Automation Tech (LV Products) product story

Edited by the Engineeringtalk editorial team Sep 23, 2003

A new range of IndustrialIT-enabled soft starters for motor currents from 30 to 1050A (inline) are claimed to be as easy to set up and operate as a mobile phone.

ABB's new PST range of IndustrialIT-enabled soft starters for motor currents from 30 to 1050A (inline) matches the latest power electronics with smart circuitry and interactive software which makes them as easy to set up and operate as a mobile phone.

The main function of a soft starter is to control AC motors to ensure smooth starting by providing a gradual, controlled increase of voltage.

This reduces voltage drops, minimising the starting current and eliminating current spikes as well as reducing mechanical stress on couplings, gearboxes and bearings and improving motor life.

ABB has pioneered the design and manufacture of soft starters since the early 1980s and this wealth of experience and extensive customer feedback has been incorporated in the development of the new state-of-the-art PST soft starter range.

The new PST soft starter has an LCD with four pushbuttons on the keypad and is just as simple to operate as a mobile phone.

The display presents all the information needed for the setup, adjustments and troubleshooting.

All information is shown in plain text and the user can choose between almost a dozen available languages.

Which means there are no coded messages to be translated or interpreted.

If desired, the user can set a password to prevent unauthorised changing of the settings.

Standard settings are available for many common applications such as pumps, conveyors, mixers and crusher drives.

It is also very simple for a customer to tailor their own settings with start/stop profiles, sequence starting of up to three motors, advanced warning profiles and other specific functions.

In addition, the display is used to present the current status of the motor and an event log, which lists the last 20 events.

In common with ABB's existing PSS range, the PST soft starters can be connected either in line with the motor or inside the delta circuit of a motor like a star-delta starter.

Inside delta connection exposes the starter to just 58% of the inline current.

A smaller starter can then be selected, which saves both space and money.

The PST automatically detects the connection mode, which means that no special settings are necessary.

The PST incorporates an advanced electronic motor overload protection that can be set to four different tripping classes.

It is also possible to set a dual overload protection so that one tripping class applies during the start-up and another one during continuous running.

If required, underload protection can also be set.

Furthermore, the starter provides protection against locked rotor, phase imbalance, phase reversal and high current.

PST is designed to handle continuously a 15% overcurrent, so it has a service factor of 115%.

In addition to the advanced motor protection, the PST has its own built-in self-protection and fault detection which allows users to design their own specific early warning system to indicate potential problems before they occur, enabling preventive action to be taken to avoid unnecessary downtime.

The PST has three output signal relays programmed to signal run, top of ramp and event.

Each of these relays can be individually programmed for any of these functions.

The event function provides a series of alternative protection, fault and warning signals that can be individually switched on and off.

The PST has three communication modes: keypad, hard-wired and bus connection.

Bus connection uses ABB's sophisticated FieldBusPlug (FBP), which ensures simple and quick connection to the bus.

The PST softstarter has a "neutral", fieldbus-independent interface that facilitates its connection to any existing protocol within the FieldBusPlug range, such as Profibus DP and DeviceNet.

The PST softstarters are ABB IndustrialIT enabled.

As IndustrialIT components they constitute "building blocks" for use in larger systems and incorporate functionalities that permit seamless integration into real-time automation systems.

The largest sizes PSTB for 370-1050A are provided with an integrated bypass contactor as standard, which reduces power losses and saves costs.

Thanks to its compact design and integrated features, the PST soft starter does not require any additional equipment, which leads to simpler installation and troubleshooting.

The PST complements ABB's existing PSS range of soft starters for 3 to 515A.