3 replies to this topic

[mrmediumvoltage]

Does anyone have experience applying soft starters on synchronous motors? How is proper field protection and application achieved?

[marke]

Hello mrmediumvoltage

My experience is limited and very old!
The applications that I was accociated with many years ago, the motors were started as induction motors and then swiched to synchronous motor control. In this case, we applied a soft starter to the stator, and bridged the soft starter at full speed. The synchronous excitation etc were applied once at full speed, in the traditional manner.

Best regards,

[marke]

Hello mrmediumvoltage

My experience is limited and very old!
The applications that I was accociated with many years ago, the motors were started as induction motors and then swiched to synchronous motor control. In this case, we applied a soft starter to the stator, and bridged the soft starter at full speed. The synchronous excitation etc were applied once at full speed, in the traditional manner.

Best regards,

[jraef]

We do it all the time. As Marke described it, the starting function is no different than using any other starting method on the ammortisseur winding, it is just imperitive that the soft starter be in Bypass before the field is energized. We just interlock the Field Application Relay control to an Auxiliary contact of the Bypass Contactor. The excitation system can be / is the same. In many cases users will reuse the existing exciter system if it is relatively new and in good working order.