Static or Soft-Starter

The advancement of electronics has allowed for the creation of the electronic starter which focuses on a set of thyristor pairs, one on each power terminal of the electric motor. In addition to the advantage of voltage and current control during startup, the electronic switch offers the advantage of having no moving parts or an electric arc generator, such as mechanical switches. This is one of the favorable points of the electronic keys, because their useful life is longer, allowing up to hundreds of millions of maneuvers.

The firing angle of each pair of thyristors is controlled electronically for a variable voltage to the motor terminals during acceleration. This behavior is called softstarter – “soft start”. At the end of the starting period, adjustable according to the utilization, the voltage reaches its total value after a gentle acceleration, instead of being subjected to sudden increments or “jumps”, as with the autotransformer starting and star-delta connection methods . With this, it is possible to keep the starting current within the stipulated limit and with smooth variation and the current limit value allowed in the electric motor is a function of the application and the design of the motor.