3 phase star delta motor

Thread Starter


Joined Feb 1, 2014
I am using 3 phase induction motor (quarter hp) and i have to use star delta starter (by using 3 to 5 contactors) that is my project condition.
Issue is that the motor i bought is (200Vac delta/380Vac star) specification. And i have 1 phase available .

What should i do ?
Do i need to purchase 1 phase to 3 phase converter ?
And if i purchase converter how i provide 380vac starter at star network and then 220vac at delta network.


Joined Jan 8, 2017
The idea of using a star/delta starter is to reduce the initial starting current. This would not normally be done with such a small motor as 0.25 HP. You motor is designed to be run directly from the three phase mains supply (220 volts neutral to phase, 380 volts phase to phase.) when connected in star configuration. Lower cost single to three phase converters only give 220 volts phase to phase voltage so to use your motor with this type of converter it would be configured as delta. (Converters with 380 volts phase to phase voltage are available to run motors that cannot be changed for 220 volt operation but they are more expensive.) Going back to star/delta starting it would be used with a 380 volt (Phase to phase.) mains supply. The motor would be rated for 380 volt (In delta.) but the starter would initially connect it in star to reduce the starting current and after a delay switch it to delta. NOTE an electronic thee phase converter (Normally called a VFD) must NOT have any switching between it's output and the motor so this would rule out the use of star/delta starting.


Thread Starter


Joined Feb 1, 2014
Thanks for your reply!

So what should I do to implement star delta starter what i need?

Motor with what specs?(380vac star/ 220vac delta)?(380vac star & delta)?

Secondly how i cam implement this attached circuit diagram and what specs needed?

What i need kindly guide me for example: do i need proper 3 phase/2 phase/1 phase or motor with what specifications ?

And sorry for the silly questions.