ABB’s PST Series Soft Starters – Product Spotlight

ABB’s PST Series Soft starters are microprocessor-based products designed for the soft start and soft stop of squirrel cage motors. The soft starter has several advanced motor protection features as standard. With their start and stop functions, they are able to control the acceleration or deceleration of a motor, while also maintaining an optimal voltage for the motor during start up.



ABB’s PST series of softstarters, available at! This unit featured is the PST series softstarter (item number pst105-600-70)


The PST series also offer current limit, which can be switched off with the kick start option for when there might be initial friction preventing the motor from turning right away.  The start and stop range can also be extended.

The units can also offer protection for pumps with a torque control function developed for pump stop to prevent water hammering and pressure surges.  Other protection that the softstarts offer is motor over and underload, locked rotor, overcurrent, phase imbalance and reversal,  and SCR overload protection.

The PST softstarters are equipped with extra terminals making the connection of an external by-pass contactor easier and allowing all protections to be active during by-pass. On the PST softstarters, an ABB AF-contactor is already built-in, ensuring a compact starting solution with minimal wiring during installation. By-passing the softstarter after reaching full voltage will save energy and reduce heat generation.

The analog output terminals can be connected to an analog current meter to show the current during operation and thereby eliminating the need for an additional current transformer. The analog output signal can also be used as an analog input to a PLC.

The PST softstarter is equipped with a full text display to make set-up easier and to provide accurate information. There are standard settings for many common applications, such as centrifugal pump that is selectable in the software. Selecting this will automatically provide all required settings including torque control when stopping.


For more information on ABB’s PST series of softstarters  contact our experts today!


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