Starter Automation

[vinay1277]

I am new to this field. I have to devise automation mechanism for DOL starters. Logically i plan to use one relay to make momentary contact like green start button and another relay to break circuit in place of red stop button. Since motors in question are 15 to 20 HP i do not want to take chance by doing trial on them .So i request you all to help me on this . Control circuitary to operate relay mechanism is not an issue as i have full control on hardware and software part of microcontrollers . My area of concern is how to identify points where NO contacts for starting and NC contact for stopping operation are to be connected . Since architechure and working of starters is new to me i am little doubtful and not so confident . Please help.

[jraef]

Here is a NEMA version. The concepts are the same, just IEC symbology is a little different. Yours would be the "3-Wire Control" version on the right.

 

http://polk-burnett.apogee.net/pd/graphics/pdjpg/3v.jpg