Jump to content

Star Delta Starter


Recommended Posts

Welcome to the Forum

Yes, it is possible to run the delta designed motor on Star but without load. I am assuming that your motor is designed for 380V. Now if you run the motor at star, the voltage would be 1/rout3 = 380/1.73 = 220V (58%). But this motor would not run under load because the current would be reduced 0.58*0.58 = 0.33 (33%) and the torque would be reduced at 1/3. Thus the slip would be increased and motor burn after some time.


"Don't assume any thing, always check/ask and clear yourself".

Link to comment
Share on other sites

Hello NCT


When you connect a delta designed motor in star, you reduce the voltage across the windings to 1/rt(3) of the rated voltage.

This reduces the flux in the iron and reduces the maximum torque that the motor can produce.

In effect, you are reducing the rating of the motor to one third of it's design rating.

You can run the motor in star provided that the shaft torque is less than on third of the rated torque, or you increase the line voltage by rt(3)


Best regards,

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...