PSTB720-600-70 720 A 208...600 V AC Softstarter

The ABB PSTB720-600-70 is a Switch for industrial control and automation applications.

ABB PSTB720-600-70 is a softstarter rated 720 A for in-line connection and 1247 A for inside delta connection, with a main circuit range of 208 ... 600 V AC. The PSTB720-600-70 combines a 100 ... 250 V AC control supply with built-in electronic overload protection and a FieldBusPlug interface for system integration.

What are the key specifications of This unit softstarter?

This softstarter operates from a main circuit of 208 ... 600 V AC at 50/60 Hz. Its control supply accepts 100 ... 250 V AC, while the control circuit operates at 24 V DC. In in-line connection, the rated operational current is 720 A, supporting 400 kW at 400 V and 500 kW at 500 V. Inside delta connection raises the rated operational current to 1247 A, with 710 kW at 400 V and 880 kW at 500 V. The service factor is 115 %, and the starting capacity reaches 3xIe for 15 s. Ramp time is adjustable from 0 ... 120 s, and current limit is settable from 1.5 ... 7xIe.

How does This unit handle protection and control?

Integrated electronic overload protection is standard, with a dedicated overload signal relay. Four signal relays are provided: run, by-pass, fault, and overload. Analog outputs include 0…10 volts, 0…20 mA, and 4…20 mA. LED indication covers ready-to-start/standby (green), protection (yellow), and fault (red). A switch for inside delta connection is included, along with a FieldBusPlug(Standard) communication interface. The main terminals are bars with a hole diameter of 12.5 mm and a width and thickness of 40x6 mm. Control circuit connecting capacity is rigid 1 x 2.5 mm² or 2 x 1.5 mm², with a tightening torque of 0.5 N·m; main circuit torque is 45 N·m.

Comparison with other softstarter configurations

• In-line vs. inside delta: In-line connection provides 720 A and up to 500 kW at 500 V; inside delta raises current to 1247 A and power to 880 kW at 500 V.
• Control supply flexibility: The 100 ... 250 V AC control supply accommodates a wide range of control voltages, unlike fixed-voltage units.
• Integrated protection: Built-in electronic overload protection eliminates the need for separate overload relays in many installations.
• Communication: FieldBusPlug(Standard) enables network integration, whereas basic softstarters often lack a communication interface.

What are the physical and environmental specifications?

The unit measures 436 mm wide, 515 mm high, and 381 mm deep, with a net weight of 55 kg. It operates in ambient air temperatures from 0 ... +50 °C and stores from -25 ... +70 °C. Main terminals are rated IP00 according to IEC 60529, IEC 60947-1, and EN 60529. The package level 1 gross weight is 67 kg.

How does This unit integrate into a motor control system?

FieldBusPlug(Standard) communication allows connection to industrial networks. Wiring into such networks may require an external gateway or connection module; confirm cables and gateways with AutoDCSTech. The analog outputs and signal relays support monitoring and interlocking with PLCs or control systems. For precise matching of accessories and integration components, contact AutoDCSTech with your exact requirements.

What maintenance and reliability considerations apply?

Periodic inspection of main terminal torque (45 N·m) and control terminal torque (0.5 N·m) helps maintain reliable connections. The built-in electronic overload protection reduces wear on motor and starter components. Operating within the specified ambient temperature range of 0 ... +50 °C supports consistent performance. The service factor of 115 % provides margin for demanding applications.