PSTX300-600-70 Softstarter 300 A 208-600 V AC

Reliable Motor Starting with the ABB PSTX300-600-70

The ABB PSTX300-600-70 is a three-phase softstarter rated at 300 A operational current and 208...600 V AC operational voltage. It provides voltage or torque ramp control for medium to large motors, with built-in bypass for energy saving and simplified installation.

Key Specifications and Protection Features

• Input voltage: 208...600 V AC main circuit; 100...250 V AC control supply at 50/60 Hz.
• Output current: 300 A in-line connection; 515 A inside delta connection.
• Isolation: Main terminals IP00 per IEC 60529; control circuit rated 24 V DC.
• Built-in electronic overload protection with service factor 100%.
• Starting capacity: 4xIe for 10 seconds; ramp time 1...120 seconds.
• Analog outputs: 0…10 V, 0…20 mA, 4…20 mA.
• Relay outputs for RUN, TOR, and Event signals (NO).
• Detachable full graphic display with IP66 and 4x outdoor rating.

Maintenance and Reliability Perspective

From a maintenance engineer's view, This unit simplifies service through its detachable display and comprehensive diagnostics. The built-in bypass reduces heat dissipation in the cabinet, extending component life. Electronic overload protection with time-to-cool and event logging supports predictive maintenance. The limp mode maintains two-phase motor control if one thyristor set shorts, allowing controlled shutdown. Ambient operating temperature range of -25...+60 °C suits demanding environments.

Communication and Integration

The softstarter includes built-in Modbus RTU and supports optional ANYBUS modules for Profinet, Profibus, Modbus TCP, Ethernet IP, and others. Hardwire inputs Start/Stop/Reset and three programmable digital inputs provide flexible control. Integration note: wiring into fieldbus networks may require an external gateway or connection module; confirm cables and gateways with AutoDCSTech.

Applications and Use Cases

Typical applications include pumps, fans, compressors, and conveyors. The auto phase sequence detection and pump cleaning function reduce commissioning time. Torque control ramps minimize mechanical stress on belts and gearboxes, while the stand-still brake holds loads securely.

Installation and Setup

Mount the softstarter vertically with adequate clearance for airflow. Main circuit bars accept hole diameter 10.2 mm and require 25 N·m tightening torque. Control circuit rigid conductors up to 2.5 mm² connect via spring terminals. Verify control supply voltage within 100...250 V AC before energizing.