Overview - ABB PST30 Installation And Maintenance Manual

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3.2
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Chapter 3 - Description
This chapter describes the softstarter in general, specifications and available accessories and
spare parts.

3:1 Overview

The PST softstarter is a microprocessor-based softstarter designed with the latest technology for
the soft start and soft stop of squirrel cage motors. The softstarter has several advanced motor
protection features as standard.
The softstarter is designed to be used with or without a by-pass contactor except for the larger
sizes, PSTB370...1050 where the bypass contactor is integrated. In an emergency, it is possible
to start the motor across the line with the integrated bypass contactor. See Section 3:8.4 for AC3
ratings.
The keypad on the front is designed to be as user-friendly as possible, with a clear text display. It
is possible to choose between twelve different languages (default is English).
The softstarter can be controlled in four ways:
• Hardware inputs
• Keypad control (local)
• Fieldbus communication interface
• Remote keypad (option)
The integrated fans for cooling are operated only during ramping (start/stop) and when the tem-
perature of the heat sink is too high. The temperature is monitored by a thermistor.
Only one type of control method can be enabled simultaneously.
Default selection is hardware inputs.
Information!
Keypad control has the highest priority and overrides all other control methods.
3:2 Functions
The PST softstarter has several integrated protection and warning functions. Almost any type of
fault can be detected and displayed.
All available protections, warnings and fault indications are listed below.
Start/Stop functions
• Start ramp
• Stop ramp (also called soft stop or decel)
• Initial voltage
• Step down voltage
• Current limit
• Kick Start
• Extended start range
• Extended stop range
• Sequence start
Protection functions
• Motor overload protection
• Locked rotor protection
• Motor underload protection
• High current protection
• Phase imbalance protection
• Phase reversal protection
• SCR overload protection
• PTC input for motor protection
• Shorted SCR
Low Voltage Products & Systems
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