A soft starter eliminates the undesired side effects. Several types based on control of the supply voltage or mechanical devices such as slip clutches were developed. The list provides an overview of the various electric start-up types. The current and torque characteristic curves show the behavior of the respective starter solution. Torque surges entail high mechanical stress on the machine, which results in higher service costs and increased wear. High currents and current peaks lead to high fixed costs charged by the power supply companies (peak current calculation) and to increased mains and generator loads.A soft starter continuously controls the three-phase motors voltage supply during the start-up phase. This way, the motor is adjusted to the machines load behavior. Mechanical operating equipment is accelerated smoothly. This lengthens service life, improves operating behavior, and smooths work flows. Electrical soft starters can use solid state devices to control the current flow and therefore the voltage applied to the motor. They can be connected in series with the line voltage applied to the motor, or can be connected inside the delta (Î”) loop of a delta-connected motor, controlling the voltage applied to each winding. Solid state soft starters can control one or more phases of the voltage applied to the induction motor with the best results achieved by three-phase control. Typically, the voltage is controlled by reverse-parallel-connected silicon-controlled rectifiers (thyristors), but in some circumstances with three-phase control, the control elements can be a reverse-parallel-connected SCR and diode.