ABB PSTX570-600-70 570A Soft Starter for Three-Phase Motors

The ABB PSTX570-600-70 is a high-performance soft starter from the PSTX series, designed for smooth starting and stopping of three-phase induction motors in industrial applications. With a rated maximum operational current of 570 A and an operating voltage range from 208 to 600 V AC, this soft starter is suitable for controlling medium to large three-phase motors in applications such as pumps, fans, compressors, and conveyors. The PSTX570-600-70 incorporates a built-in bypass for energy savings and easy installation, along with comprehensive protection functions to extend motor life and reduce electrical stress during starting and stopping.

Key Specifications

• Model: PSTX570-600-70 Soft Starter

• Brand: ABB (1SFA898117R7000)

• Rated Operational Current: 570 A (inline connection)

• Maximum Current (Inside Delta): 814 A

• Operating Voltage: 208 to 690 V AC, 50/60 Hz

• Control Voltage: 100 to 250 V AC, 50/60 Hz

• Control Method: Voltage ramp or torque ramp

• Built-in Bypass: Standard for energy saving

• Degree of Protection: IP00, NEMA 1

• Weight: 27 kg

• Country of Origin: Sweden

Soft Start and Soft Stop Capabilities

The PSTX570-600-70 provides smooth motor starting and stopping through voltage ramp or torque ramp control methods. Traditional across-the-line starting applies full voltage immediately, causing high inrush currents (typically 600-800% of full load current) and mechanical shock to the driven load. The soft starter gradually increases voltage during startup, reducing starting current and minimizing mechanical stress on motors, belts, gears, and couplings. Soft stop functionality gradually reduces voltage during stopping, preventing water hammer in pumping systems and load shock in conveyor applications. These features extend equipment life and improve operational reliability.

Built-in Bypass for Energy Efficiency

The PSTX570-600-70 incorporates a standard built-in bypass contactor that eliminates the power losses associated with continuous thyristor operation. After the motor reaches full speed, the internal bypass closes, conducting current directly to the motor while the thyristors are turned off. This bypass operation reduces heat dissipation, eliminates the need for external bypass contactors, and improves overall system efficiency. The built-in bypass simplifies panel design, reduces wiring requirements, and saves valuable enclosure space compared to external bypass configurations.

Motor Protection Functions

The soft starter integrates multiple motor protection functions to safeguard the motor and driven equipment. Overload protection uses electronic thermal modeling to prevent motor overheating. Current limiting restricts starting current to user-defined levels, protecting the power supply and reducing voltage drop on the distribution system. Kickstart provides an initial voltage boost to break away stuck or high-friction loads. Pump cleaning function periodically operates the pump to prevent sediment buildup. The built-in protection eliminates the need for separate overload relays in many applications, reducing panel complexity and component count.

Graphic Display and User Interface

The PSTX570-600-70 features a detachable full graphic display with IP66 and outdoor rating, providing intuitive access to parameters, monitoring data, and diagnostics. The display shows motor current, voltage, power, and temperature in real time, allowing operators to verify proper operation at a glance. The menu-driven interface simplifies parameter configuration, with wizards guiding users through setup for different application types. The display can be mounted remotely on the enclosure door for convenient access, with the main unit installed inside the control cabinet.

Fieldbus Communication and Integration

The PSTX570-600-70 supports multiple communication options for integration into automation networks. Built-in Modbus RTU provides standard serial communication for connection to PLCs, SCADA systems, and building management systems. Optional ANYBUS modules enable communication protocols including Profinet, Profibus DP, Modbus TCP, and Ethernet IP. The communication capabilities allow the soft starter to be monitored and controlled remotely, with parameters adjustable, status monitored, and faults acknowledged from a central control room. The fieldbus connectivity supports Industry 4.0 and IIoT applications for predictive maintenance and process optimization.

Advanced Control Functions

The PSTX570-600-70 includes advanced control functions as standard features. Jog operation allows inching of the motor for positioning or setup purposes. Braking provides controlled stopping for applications requiring rapid deceleration. Stand-still brake holds the motor stationary when stopped, preventing load creep. Sequence start coordinates multiple soft starters to start in sequence, reducing total inrush current on the power supply. Emergency/fire pump mode overrides certain protection functions to maintain operation of critical pumps during fire conditions. These advanced functions expand the application range of the soft starter beyond basic starting and stopping.

Programmable Digital and Analog I/O

The PSTX570-600-70 provides three programmable digital inputs for connection to PLC outputs, pushbuttons, selector switches, and other control devices. These inputs can be configured for start, stop, reset, local/remote selection, and other functions. Relay outputs provide RUN, TOR (Top of Ramp), and event status signals in normally open configuration, allowing the PLC to monitor soft starter status. An analog output provides a 0-20mA or 4-20mA signal proportional to motor current, enabling remote monitoring of motor load from a PLC analog input module.

Diagnostic and Event Logging

The PSTX570-600-70 includes comprehensive diagnostic capabilities for system monitoring and troubleshooting. Event logging records soft starter operations, parameter changes, and fault events with timestamps, supporting root cause analysis and predictive maintenance. The end-of-life (EOL) prediction function estimates remaining life of the internal bypass contactor, allowing proactive replacement before failure. The diagnostic data can be accessed via the graphic display or through fieldbus communication, enabling remote monitoring and maintenance planning.

Industrial Applications

The ABB PSTX570-600-70 soft starter is deployed across a wide range of industrial motor control applications. In pumping systems, it provides smooth starts and stops to prevent water hammer and pipe stress. In fan and blower applications, it reduces starting current and eliminates belt slippage. In compressor applications, it limits inrush current and reduces mechanical stress on drive components. In conveyor systems, it provides controlled acceleration and deceleration to prevent product damage. The soft starter's high current rating makes it suitable for motors up to approximately 315 kW (400V) depending on load characteristics.

Conclusion

The ABB PSTX570-600-70 soft starter delivers smooth starting and stopping for three-phase motors with 570A rating, 208-600VAC operation, built-in bypass, and comprehensive protection functions. Its graphic display, fieldbus communication options, and advanced control features make it a versatile solution for demanding industrial motor control applications.