Check the star point contactor in the Y-D starter. If that's dead then it won't work. Obviously the two main contactors should pull in when expected too. Are the timers set correctly (if used?) or is the transfer from Y to D based on current draw?
----------------------------------
If we learn from our mistakes I'm getting a great education!
It most likely is a problem in the starter as ScottyUK says. Either the control circuit has been altered to forgo the Star step and just immediately go to Delta, or timer is set incorrectly and the Star step is so short that you don't notice it.
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376
You aren't related to this user by chance are you? Incredible coincidence that you are both having similar problems at the same time.
thread238-298383
"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376
Check that current is flowing on all three phases in the star connection.
If this is true, the current should be about 2 x the rated current of the motor, then the problem is probably that you are trying to start a load that requires a high starting torque and the star/delta starter is not correct for this application.
