Calculation
Iline = √3 · Iphase
In delta, two phase currents offset by 120° add geometrically to the line current; the factor between them is always √3.
Busch 2006, Abschnitt 5.11.3, Gl. (5.98) und (5.99)
Delta connection: line current from phase current
In delta, two phase currents offset by 120° add geometrically to the line current; the factor between them is always √3.
MINTSI
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Result
Select a target and calculate.
Understand the inputs
- Line current Iline — RMS current in each of the three line conductors of the delta-connected load.
- Phase current Iphase — RMS current through a single phase of the delta connection.
Example
Iphase=10 A gives Iline=√3·10≈17.32 A.
Assumptions and limits
Balanced delta connection with equal phase currents and 120° phase offset; imbalance is excluded.
Understand Delta connection: line current from phase current
This calculator converts between phase and line current of a balanced delta connection, the current-side counterpart to the wye connection.
What does this quantity describe?
In a delta connection, each phase sits between two line conductors. At each node, two phase currents offset by 120° meet and add geometrically to the line current: Iline=√3·Iphase.
Formula and variables
Iline = √3 · Iphase
Iline = √3 · IphaseIphase = Iline / √3
| Symbol / input | Meaning |
|---|---|
| Line current Iline | RMS current in each of the three line conductors of the delta-connected load. |
| Phase current Iphase | RMS current through a single phase of the delta connection. |
Choose the inputs correctly
Iphase is the current through a single phase of the delta connection, Iline the current in each line conductor.
How to use the calculator
Take one of the two quantities from a nameplate, calculation or measurement; the other follows directly from the factor √3.
Worked example
Iphase=10 A gives Iline=√3·10≈17.32 A.
Understand the result and units
Line current always exceeds phase current; conversely, for a given power, phase current is lower than line current.
Iphase and Iline are currents.
Typical applications
Converting between supply current and winding current for delta-connected motors and transformers, e.g. in star-delta starting.
Assumptions, limits and common mistakes
Balanced delta connection with equal phase currents and exact 120° offset; imbalance is excluded.
Common mistake: Do not confuse line current with phase current when sizing a winding for the smaller phase current.
Frequently asked questions
What is “Delta connection: line current from phase current” used for?
Converting between supply current and winding current for delta-connected motors and transformers, e.g. in star-delta starting.
Where do the input values come from?
Iphase is the current through a single phase of the delta connection, Iline the current in each line conductor.
What does the result not cover?
Balanced delta connection with equal phase currents and exact 120° offset; imbalance is excluded.