PSTX1050-600-70 | ABB 1050 A 208-600 V AC Softstarter

What causes motor starting stress in heavy-duty applications?

Direct-on-line starting subjects medium and large three-phase motors to high inrush currents and mechanical shock. The ABB PSTX1050-600-70 softstarter addresses this by controlling voltage or torque ramp during start and stop. It is rated for 1050 A in-line connection and 1810 A inside delta connection, with an operational voltage span of 208...600 V AC.

Key features and precise electrical specifications

• Rated operational current (in-line): 1050 A for continuous service.
• Rated operational current (inside delta): 1810 A for higher capacity without oversizing.
• Rated operational voltage: 208...600 V AC, 50/60 Hz.
• Rated control supply voltage: 100...250 V AC at 50/60 Hz.
• Rated control circuit voltage: 24 V DC.
• Starting capacity: 4xIe for 10 s, with ramp time 1...120 s.
• Current limit function: 1.5...7.5 xIe, adjustable.
• Analog outputs: 0…10 V, 0…20 mA, 4…20 mA.
• Communication: Modbus RTU built in; optional ANYBUS modules for Profinet, Profibus, Modbus TCP, Ethernet IP, and others.
• Degree of protection: Main terminals IP00 according to IEC 60529.

These verified parameters support engineering-grade precision in motor starting design. The built-in bypass reduces energy losses during run, while electronic overload protection with time-to-cool prevents thermal damage.

How does the PSTX1050-600-70 handle different motor starting profiles?

The softstarter offers voltage or torque ramp control, current limit, and kickstart for high-friction loads. Dual current limit and step-down voltage special ramp (100...10%) accommodate complex starting sequences. For pump applications, pump cleaning and motor heating functions help maintain performance. The three-phase control ensures balanced currents, and auto phase sequence detection simplifies commissioning.

Integration and communication options

Hardwire inputs for Start/Stop/Reset of fault and three programmable digital inputs provide basic control. Built-in Modbus RTU enables direct network connection. For other protocols, optional ANYBUS modules support Profinet, Profibus, Modbus TCP, Ethernet IP, EtherCAT, DeviceNet, CANopen, BACnet-IP, and BACnet-MSTP. A detachable full graphic display with IP66 and 4x outdoor rating allows local configuration and monitoring. Integration note: wiring into fieldbus networks may require an external gateway or connection module; confirm cables and gateways with AutoDCSTech.

Typical applications and installation guidance

Pumps, fans, compressors, and conveyors benefit from controlled starting. The inside delta connection allows 1810 A rating for large motors without increasing panel size. Install the softstarter vertically with adequate clearance for heat dissipation. Main circuit bars require 45 N·m tightening torque. Control circuit rigid conductors up to 2.5 mm² connect to the terminals. Ambient operating temperature range is -25...60 °C; ensure enclosure ventilation matches the 62.3 kg unit's thermal load.

Reliability and protection functions

Built-in electronic overload protection, current imbalance, underload, earth fault, locked rotor, and over/under voltage protections safeguard the motor and starter. The event log and diagnostics simplify troubleshooting. Periodic inspection of cooling fans and terminal torque is recommended. The service factor is 100%, and the starting capacity of 4xIe for 10 s suits most industrial duty cycles.

Technical specifications summary

• Rated operational voltage: 208 ... 600 V AC
• Rated operational current (in-line): 1050 A
• Rated operational current (inside delta): 1810 A
• Rated control supply voltage: 100 ... 250 V AC
• Rated control circuit voltage: 24 V DC
• Rated frequency: 50/60 Hz
• Starting capacity: 4xIe for 10 s
• Ramp time: 1 ... 120 s
• Analog outputs: 0…10 V, 0…20 mA, 4…20 mA
• Degree of protection: Main terminals IP00

Contact AutoDCSTech with your exact requirements for precise matching of this softstarter to your application.