Dear All,
This is my first time using auto transformer in motor system design.
From my reading, the sequence of starting auto transformer is (using 3 magnetic contactors in system design) :
1) Initially, The Star Switch is closed
2) Then, The Start Switch is closed to energize the autotransformer
3) The motor is connected at a selected reduced voltage tap on the autotransformer and start to turn and accelerate.
4) After a predetermined period the Star Switch will open.
5) After a mili-sec delay, the Run Switch will close, connecting full line voltage to the motor.
6) The Start Switch will then open and the motor will be at operational speed.
My question is,
1) how to to determine value of step no 4?
2) what the ideal delay timer for step no 5?
Autotransfomer that I'm working is for start up run of motor compressor . All the sequence control by PLC.
Thanks a lot for ur reply.
This is my first time using auto transformer in motor system design.
From my reading, the sequence of starting auto transformer is (using 3 magnetic contactors in system design) :
1) Initially, The Star Switch is closed
2) Then, The Start Switch is closed to energize the autotransformer
3) The motor is connected at a selected reduced voltage tap on the autotransformer and start to turn and accelerate.
4) After a predetermined period the Star Switch will open.
5) After a mili-sec delay, the Run Switch will close, connecting full line voltage to the motor.
6) The Start Switch will then open and the motor will be at operational speed.
My question is,
1) how to to determine value of step no 4?
2) what the ideal delay timer for step no 5?
Autotransfomer that I'm working is for start up run of motor compressor . All the sequence control by PLC.
Thanks a lot for ur reply.