How does soft start compare with star/delta starting?

Compared with star/delta starters, soft starters are much more flexible and provide a smooth start with no risk of transients.
Star/delta starters offer limited performance because:

• Start torque cannot be adjusted to accommodate motor and load characteristics.
• There is an open transition between star and delta connection that results in damaging torque and current transients.
• They cannot accommodate varying load conditions (eg loaded or unloaded starts).
• They cannot provide soft stop.

The main advantages of star/delta starters are:

• They may be cheaper than a soft starter.
• When used to start an extremely light load, they may limit the start current to a lower level than a soft starter. However, severe current and torque transients may still occur.