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3 key differences between variable-speed drives and soft starters

When it comes to electric motor control, variable-speed drives and soft starters are two of the options available to users. There are some crucial differences between these pieces of equipment, and we’ll take a quick look at three of them here.

Energy savings

A soft starter allows the electric motor to start with reduced voltage, meaning full speed is achieved smoothly. While this offers reasonable energy savings, the fact that a variable-speed drive allows electric motor speed control beyond the starting phase means its potential for energy efficiency is much greater.


Soft starters usually require only basic maintenance such as ensuring fan vents are clean and free of debris. For drives (especially those in constant operation), regular inspection of cooling fans, motors and connections should be carried out to ensure the equipment maintains its reliability.

Full torque at zero speed

Soft starters cannot provide full torque at zero speed as they run on a fixed frequency; however, variable-speed drives are able to achieve this which removes the need for a mechanical brake. This means applications such as inclined conveyors can be held in position when stopped rather than moving backwards.

Gibbons are a founder member of the Authorized Value Provider network, which means we’re approved to supply and service ABB drives for a wide range of applications, including pumps, fans and conveyors. For more information, contact our Drives Manager Alan Roberts on 07966 468430 or email

Variable-Speed Drives

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