Hi guys,

Just looking for some feedback with respect to Soft Staring a drive as compared to Start-Delta starting it.

Assume a relatively small size of 15kW.

The aim is to reduce starting current.
Factors to consider: Cost, wear and tear, reliability due to feeder surges etc...

What would be recommended ?

Hello cpapas

I would never recommend a star/delta (wye/delta) starter except for some extreme cases. The problem is that the starting torque is fixed and can not be altered to suit the load, it is often too low to accelerate the motor to full speed, and the transition to full voltage ia an open transition and causes major torque and current transients to occur. These transients can result in a high level of damage to the supply, motor and driven load. A DOL starter may draw a higher continuous current for a longer period of time than the star/delta starter, but does not have the open transition transient that causes most of the damage and interference.

A good soft starter will enable the current to be limited to only what is needed to start the load, it will eliminate transient damage and wear and tear.

Best regards,