Does a soft starter on fixed speed motor better than VFD?

We see that the market is changing and clients are looking to optimize their process rather than just fit a VFD for all applications. Fitting a VFD on a fix speed motor will not give any benefits and using a soft starter will be more economical for the client and the process.

There are many real world examples of soft starters with an energy saving algorithm reducing the energy consumption of a lightly loaded motor but please be aware that not all soft starters have this feature.

The energy saving system reduces energy consumption by directly matching the amount of energy supplied to the motor to the amount of energy required by the motor at that specific load.

The amount of savings possible depends heavily on the type of application, the amount of load, the specific motor and specific load. It is impossible to give an estimated saving without detailed information on both the application, motor and site information.

However, if a motor is lightly loaded and depending on the type of application we could expect to see savings of between 8 and 32% saving on the energy consumed by the motor. While this seems obvious to those of us in the soft starter industry, it seems many end users still use VFDs for fixed speed applications when a soft starter would be a more cost effective, efficient and reliable choice.