Soft Starters vs. DOL Starters

Dear Sirs,
I have a 120 KW AC motor that is being started / run by using DOL Starter.
I want to change the starter by a Soft Starters cum Energy Saver.
Can someone suggest me the following -
1. Advantages of using a soft starter
2.Effect on Life of the motor
3. Tentative Power saving (approx)
Erric Ravi
120Kw seems rather high for a DOL unless it is MV/HV.
If it were 20Kw (LV) Soft Start would be an addition to the existing DOL starter.
It would be very useful in reducing starting currents for motors that have almost
no starting load such as extract fans - or any other type of fan for that matter.

Reduced starting currents would have a marginal effect on motor life and believe difficult to calculate
Reducing mechanical shock on pumps depends on type of pump and the media involved.
My extensive experience in the water industry hasn't seen many companies opt for soft starts.
Having said that, most large pumps justify variable speed drives.

Reduced starting currents could improve both power factor and peak current tarrifs for small factories.
The only times I have seen peak current/power factor tarrifs being an issue for starting several large motors is to
have sequential start up.
As to the "energy savings", that is something that is often over sold on Soft Starters and in fact many manufacturers have ceased offering it as a feature. It only worked on UNLOADED motors, by reducing a small amount of the energy used to magnetize the windings since torque was not needed. In reality, why would you be running a motor that is not doing anything? The ultimate "energy saver" in that circumstance is the OFF button. In addition, it cannot function if you use a Bypass Contactor on the Soft Starter, which means the enclosure must be ventilated to prevent over heating. Most Soft Starters are sold with Bypass Contactors now, so the energy saver function was pointless. There is not energy savings from just soft starting alone. The energy it takes to accelerate a load from full stop to full speed is ALWAYS the same; it's a function of physics. All a soft starter does is exchange the PEAK for TIME; lower peak, longer time. But the area under the curve representing the total energy input is exactly the same.

Anyone who is trying to sell you on there being energy savings with a soft starter is scamming you.