Soft starter ratings.

[Marke]

There are many different ways in which esigners determine the ratings that they will apply to soft starters. This results in a wide disparity in the reliability of products under equal conditions and leads to a lot of confusion for the end user. There are some standards, such as IEC60947-4-2 that decribe how soft starters will be rated, but these do not cover how the ratings should be derived. I have a small discussion at :

http://www.lmphotonics.com/forum/viewthread.php?tid=391

and I am interested in any ideas or information that you have.

Best regards,

Mark Empson

http://www.lmphotonics.com

 

[jbartos]

Comment: Often, a soft starter size is selected from the manufacturer literature or via the manufacturer tech support recommendation. To deviate from it or challenge it, it is necessary to have the better background than these sources, which is rarely the case for an application engineer dealing with other items than soft starter selections. Also, the soft starter principles may somewhat vary as well as switching devices, which somewhat impact the selection of software starter sizes.