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As far as I've seen, low voltage distribution lines (3-Phase 440 volts) have four wires - three phases and one neutral (Ignore the earth cable). What should I do with the neutral line if I want to run an induction motor with a Delta-Star starter? I know that the delta connection does not need neutral. But in Star connection, should I connect the Neutral with the common terminal of the Star?

Online documents and books have ignored the neutral line. As far as I know, the output of the distribution transformer (11KV Delta / 440 Wye) sometimes gets unbalanced.

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As far as I know, the output of the distribution transformer (11 kV Delta / 440 Wye) sometimes gets unbalanced.

That would be a very good reason not to connect the motor star / wye point to neutral. The motor - if all is well with the windings - will have its star / wye point centred between the three phases. Connecting this to neutral may result in uneven voltages applied to the motor's three windings.

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N is not used from the source in a Squirrel Cage Motor (SCM) .

Rather a 3P2T transfer switch is used only from the 3Ph Delta source to boost the voltage per windings in Star Mode with <50% rated load torque for starting then switched to Delta across each pair for Run mode to reduce excitation currents and improve PF.

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There are plenty of Youtube video explanations too.

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