star-delta start up

[Anton85]

Iv got a star-delta start up in place,however the motor isn't starting in star but is kicking in at full speed on delta. what could cause this?

 

[Pumpsonly]

Check your connection at the motor terminal box. You need 6 wires for star-delta.

 

[Anton85]

thanks, connections are ok, do you think i could have a problem with my windings or any other suggestions? thanks

 

[ScottyUK]

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?


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If we learn from our mistakes I'm getting a great education!

 

[jraef]

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

 

[jraef]

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

 

[Marke]

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.

What is the load that you are trying to start?

Best regards,
Mark.

Mark Empson
Advanced Motor Control Ltd

 

[krsh]

Connect the motor only on star an see if it works. After that you will now what to do.