Yes you are correct Lionel, by wiring in a n/c stop button contact into both star and delta contactors.This is the benefit of have three contactors in a star/delta system, but where a standard DOL motor contactor seizes it becomes more difficult and dangerous to stop the motor.
Normal conditions...Main contactor closes at start and remains closed whilst motor is running. The star contactor closes with the main at start (star and the delta are electrically interlocked with main contactor IE main must be closed)and is timed (nominally 10 secs)to open and when open allows...
