Key Differences between and Inverter Drive and a Soft Start expanded

There are quite fundamental differences between both the operation and the application of an inverter drive and a soft starter. The key differences are shown below,

A soft start gradually increases the voltage at the motor input terminals, at a fixed frequency, to limit starting current, which increases starting time and gives a soft start for the motor. With a soft Start there is no available speed control for the motor. While an Inverter Drive varies its output frequency, output voltage and current to the motor to allow precise control of both speed and torque. The Inverter Drive also has a built in adjustable soft start for the motor so has the best of both worlds.
Functionally the soft start is only used for starting and stopping the motor only, the inverter allows full speed and torque control of the motor. With the inverter drive actually having the ability to give the motor a more precise and controllable soft start than the soft start itself.
A soft start does not provide increased motor efficiency, the inverter drive can offer real reductions in energy consumption. This is however, application dependant, mainly fan and pump type loads.
The inverter drive offers extensive motor protection including, motor overload, short circuit, phase loss and earth faults in some circumstances, the soft starter offers only basic motor protection, which will be model dependant.
Inverter drives are generally more expensive the equivalent kW rated soft start, as a rule of thumb inverter drives tend to be roughly twice the price.
Inverter drives are almost always larger than the equivalent kW rated soft start.
Inverter dives almost always generate more heat than an equivalent rated soft start, due to fast switching output semiconductors compared to the slower switching versions in the soft start.

Key Differences between and Inverter Drive and a Soft Start expanded

There are quite fundamental differences between both the operation and the application of an inverter drive and a soft starter. The key differences are shown below,

Functionally the soft start is only used for starting and stopping the motor only, the inverter allows full speed and torque control of the motor. With the inverter drive actually having the ability to give the motor a more precise and controllable soft start than the soft start itself.

A soft start does not provide increased motor efficiency, the inverter drive can offer real reductions in energy consumption. This is however, application dependant, mainly fan and pump type loads.

The inverter drive offers extensive motor protection including, motor overload, short circuit, phase loss and earth faults in some circumstances, the soft starter offers only basic motor protection, which will be model dependant.

Inverter drives are generally more expensive the equivalent kW rated soft start, as a rule of thumb inverter drives tend to be roughly twice the price.

Inverter drives are almost always larger than the equivalent kW rated soft start.

Inverter dives almost always generate more heat than an equivalent rated soft start, due to fast switching output semiconductors compared to the slower switching versions in the soft start.