The principle of soft Starter

Soft starters (soft starters) is a set of motor soft start and soft stop, light energy saving and protection features in one of the new motor controls, abroad known as the Soft Starter. Three opposite parallel thyristor soft Starter used as voltage regulators, to access between power supply and motor. This circuit of three-phase full-bridge controlled rectifier. When using the start motor soft starter, thyristor output voltage increasing gradual acceleration of the motor until the thyristor turn-on, on the mechanical characteristics of motor operating at rated voltage, realize smooth start and reduce starting current, avoid over-current tripping. Motor rated speed is reached, the boot process ends, soft-start is automatically replaced by the bypass contactor thyristor for completed tasks, providing rated voltage for motor functioning, in order to reduce heat losses from the thyristor, extending the life of soft starter, to improve the efficiency and power avoided the harmonic pollution. Soft Starter-along with soft stop function soft start and soft stop process instead, voltage decrease, speed gradually drops to zero to avoid torque shocks due to free parking.