New features for softstarter
April 1st 2007

ABB has added two new features to its PST softstarter range; torque control and analog output.With torque control users can now select between normal voltage ramp and torque ramp for starting and stopping motors. By selecting the torque ramp for starting, the torque of the motor follows a predefined optimal curve.This ensures an even smoother start, leading to a more linear acceleration of the motor speed. For stopping motors using torque control, the voltage is adjusted so that the torque decreases from an operational level down to a value matching the preset end voltage, ensuring a smooth stop.

Torque control is especially useful for stopping pumps.Using the torque ramp a motor can now be brought to almost a complete stop without any watyer hammering or back flow occurring.

The PST softstarter is now also fitted with a programmable analog output signal, and can be set for a 0- 10V, 0-20mA or 4-20mA output. By having analog output available on the softstarter itself, there is no need to use a separate current transformer to connect the panel meter.

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