Auto-transformer Starters: How does soft start compare to auto-transformer starting? 

Compared with auto-transformer starters, soft starters are much more flexible and provide a much smoother start.
Auto-transformer starters offer limited performance because:
- they offer only limited ability to adjust start torque to accommodate motor and load characteristics.
- there are still current and torque transients associated with steps between voltages.
- they large and expensive.
- they are especially expensive if high start frequency is required.
- unable to accommodate changing load conditions. e.g. loaded or unloaded starts.
- unable to provide soft stop.