When to choose a soft starter over a variable frequency drive ( VFD )
ELECTRICAL & ELECTRONICS SOFT STARTER AND A VARIABLE FREQUENCY DRIVE ( VFD )
WEG
When to choose a soft starter over a variable frequency drive ( VFD )
In industrial settings , choosing between a soft starter and a variable frequency drive ( VFD ) can be pivotal in optimising motor performance , efficiency and cost-effectiveness . Both technologies serve the purpose of controlling motors , but their application , benefits and limitations vary significantly . Here Ali Khalil , development sales manager for high voltage solutions at industrial equipment manufacturer WEG explains that deciding when to use a soft starter instead of a VFD involves assessing four key factors : speed control , price , size and energy efficiency .
The motor starter market is poised to reach USD 13 billion by the end of 2026 , growing at a CAGR of five per cent during this period . While VFDs are versatile and suitable for almost all applications , soft starters are more specific in their use cases . This doesn ’ t mean that VFDs are easier to specify , install and commission — it simply means they are applicable to a wider variety of scenarios . Let ’ s explore when you should choose a soft starter over a VFD .
When smooth starts are enough The primary distinction between a soft starter and a VFD is to the way they control speed . A soft starter gradually ramps up the voltage to allow the motor to start smoothly , minimising torque and mechanical stress during the startup phase . However , once the motor reaches full speed , a soft starter cannot provide any additional speed control . This makes soft starters ideal for applications in conveyors , pumps and fans , where motors only need to operate at full speed and the primary concern is reducing inrush current and mechanical stress during startup .
60 PECM Issue 72