A soft starter can be explained as a device used with motors to reduce the inrush current and torque during startup for a temporary period. It makes use of a gradually increasing voltage to the motors which often results in smooth acceleration of the motor and coupled load. It offers a linear power slope which also enables smooth acceleration, which in turn, reduces in rush currents along with the excessive wear on mechanical driven elements. The starter also contains a valuable provision to adjust the starting torque and acceleration time. This can be chosen to suit different applications.
The industries which commonly use soft starters include –
- Steel industries (Rolling mills and processing lines)
- Rubber and plastic
- Paper and pulp
- Sugar plants
- Water supply scheme
- Machine tool applications
- Cement industries
- Textile industries
Their main applications include – pumps, compressors, fans, conveyors, others (crushers, mixers, grinders, etc)
The benefits of soft starters can be elaborated on as follows –
- A soft starter ensures smooth and uniform starting by torque control for gradual acceleration of the drive system which goes on to help in preventing jerks (in the case of phase 3 control starters). This extends the life of mechanical components and reduces their maintenance requirements.
- A significant reduction in starting current to achieve break-away, along with holding back the current during acceleration. Soft starters also play significant roles in preventing mechanical, electrical, thermal weakening of the electrical equipment such as motors, transformers & switchgear.
- The microprocessor version of the soft starter possesses a software controlled response at full speed which helps in monitoring energy.
- Soft starters facilitate power factor correction as well – it is a self monitoring inbuilt feature. When the motor is operating at less than full load, the relative reactive component of current drawn by the motor is redundantly excessive due to magnetizing and associated losses. Therefore the voltage dependent losses are negligible with the load proportional active current component and as a result the power factor also improves side-by-side.
#Schneider Electric is a leading brand manufacturing soft starters along with other motor control devices. The brand has established its presence all across the globe with offerings in the realms of electrical management, motor control, home automation, smart technology, and electrical protection. Some other prominent offerings include electrical switchgear – medium voltage switchgears, MCB’s, PLC’s, and HMI’s.