High Power Winding

12-strand parallel helical construction for very high current capacity. Precise transposition control between principals guarantees equal current sharing and magnetic symmetry up to 165 MVA.

Design Rationale

At 165 MVA and Ø1,322 mm, the RF winding represents the upper limit of our production capability and one of the most demanding winding geometries in industrial transformer manufacturing. Carrying rated currents at this power level requires 12 parallel flat copper strands wound simultaneously in a multi-start helical arrangement – 12×7 turns for a total of 84 distributed across 12 conductors. Managing 12 parallel current paths introduces a critical challenge: any asymmetry in the flux linkage between principals generates circulating currents that unbalance the load and generate additional losses. Transposition control between the 12 strands is therefore not a secondary consideration but a primary design constraint, solved by precisely sequencing the relative positions of the principals over the winding height.

Technical Specifications

Power Range Up to 165 MVA
Winding Diameter Ø 1,322 mm
Conductor Flat copper strip
Winding Type 12-strand helical
Turns 12 × 7 = 84 turns

Key Engineering Features

165 MVA Capability

12-strand parallel architecture enables current-carrying capacity that reaches the upper range of large power and heavy metallurgical transformer applications.

Magnetic Symmetry

Uniform distribution of the 12 conductors around the winding circumference maintains magnetic symmetry of the complete winding, critical for accurate impedance and stray loss prediction.

Principal Transposition

Controlled transposition sequence across the 12 parallel strands equalises total flux linkage per principal, ensuring even current distribution and eliminating inter-principal circulating currents.

Skin Effect Control

Multi-strand conductor subdivision reduces individual strand cross-section below the skin depth threshold at 50/60 Hz, suppressing skin effect losses in high-current applications.

Technical Note

Production Infrastructure – Winding at Ø1,322 mm with 12 simultaneous principals requires a dedicated large-bore CNC winding machine and an experienced crew with specific competency in multi-start helical geometry. C.E.M.’s winding shop is equipped and staffed for this class of work. Handling, transfer and pre-assembly of these windings is managed entirely in-house with dedicated lifting gear.