Delta Line and Phase Current
Worked example: 10 A per winding → 17.32 A line — press Try an example to run it live, then adjust anything.
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Wye and delta systems →
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Delta Line and Phase Current explained
Delta is wye's mirror image: the windings sit directly across the lines, so phase voltage equals line voltage, but each line conductor collects current from two windings that are 120° apart — giving the same √3, this time on the current. A delta motor winding carrying 10 A per coil draws 17.32 A in each line lead.
This is exactly why a wye-delta starter works. Started in wye, each winding sees only VL/√3, so the winding current drops by √3 and the line current by three; the motor starts on about a third of its delta inrush and a third of the torque, then switches to delta for full running duty. The trap in the field is the six-lead terminal box: reconnect a 400 V delta motor as wye and it runs at 58% voltage and stalls under load.
Delta Line and Phase Current formula
- = Line current (A)
- = Phase (winding) current (A)
Missing one of these? Work it out first, then come back
- Line current — Three-Phase Real Power, Single-Phase Real Power with Power Factor
- Phase (winding) current — Current Divider, Current Sharing Between Parallel Conductors