Alternative star-delta starter arrangement.

[ArikBY]

Jesper

From another view I think there is safety problem with your circuit
You need to connect the brekers together in a way when you shut down
one the second will shut too.

 

[JesperMP]

Arik,
thats a very good point !
Someone could mistakenly think that the motor terminals are safe when only one of the CBs is switched OFF.

Well that decides it. I cannot recommend the idea any more.

 

[Thomas Sullens]

I agree with ArikBy there could be a safety issue. If you change the way it`s been done for ever. Some of us old timers are slow to learn.
By the way I would think a Y delta starter would be considered a soft start sense it only developes 57% starting torque. Because of the low staring torque we`ve had trouble starting small chipper motors 250 Hp and less also bandmills. Sometimes it takes 30 seconds sometimes 200 the reason for the long start is that it trips the main breaker. As you know in the field you have to live with what ever the engineers design and send with the equipment.