Why Use a Soft Start?

Are you experiencing mechanical or electrical problems?

The financial consequences are considerable; every technical problem and every breakdown costs money in terms of repairs as well as lost production.

Electrical problems due to voltage and current transient arising from Direct-On-Line or Star-Delta starts. Such transients may overload the local supply network and cause unacceptable voltage variations that interfere with other electrical equipment connected to the network.

Mechanical problems that address the entire drive chain,from motor to driven equipment, causing a big need for service and repair as well as unwanted down time.

Operational problems, such as damage to products on conveyor belts.

Water hammering and pressure surges in pipe systems when starting and stopping pumps.

The easy solution to all of these problems is to install an ABB Softstarter type PSR, PSS, PSE or PST(B). With ABB Softstarters, it is possible to start and stop smoothly while keeping mechanical and electrical stresses to a minimum.

Differences between different starting methods


Graphs showing the basic differences between Direct-On-Line starting (DOL),
star-delta starting and soft starting in terms of the motor voltage (U), motor current (I) and motor torque (T).