3.1.25 Frequency converter vs. soft start – what is the difference?
A frequency converter and a soft starter differ mainly in function, controllability and application area:
frequency converter
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Continuously regulates speed and torque
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Changes the frequency and voltage of the motor
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Enables stepless speed control, direction of rotation change and braking functions
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Ideal for applications with variable speed (e.g. conveyor belts, pumps)
soft start device
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Only reduces the starting current and starting torque.
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Only works during start and stop
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No speed control during continuous operation
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Suitable for constant speed motors (e.g., pumps, fans)
In short
Frequency converter = Starting and control
Soft start device = only gentle starting
