Week 07
Three-Phase Transformers
I revisit magnetic circuits, transformers, and rotating machines around my transformer report and calculation sheets.
What I connect in this unit
Wye and delta connections create different phase-to-line voltage and current relations and impose a phase displacement. Whether three single-phase units form a bank or one three-phase core is used, rating follows line voltage and line current, and connection also determines neutral and harmonic-current paths.
Concept map
- Wye and delta connections
- Phase displacement
- Transformer banks
- Rating calculations
Technical anchor
Balanced three-phase rating is S_3phi = sqrt(3) V_LL I_L; in wye, V_phase = V_LL/sqrt(3), while in delta, I_phase = I_L/sqrt(3).
How I review it
Redraw vector-group clock notation with dot polarity as phasors, then verify that phase voltage and current on each winding remain within individual winding ratings.
Connection to the full course
Unit 7 of 12. Unit numbers expand the saved report and calculations into a reading sequence rather than an attendance record.