Introduction
This article explains the benefits of thin copper strip for transformer windings. Copper strip is rolled to precise thickness tolerances for electrical, thermal and industrial applications where sheet products are too thick or too wide. It is the base material for transformer windings, bus bar laminations, lead frames, heat spreaders and a wide range of stamped components.
Production and Tolerances
Copper strip is produced by hot rolling, cold rolling and annealing to the required temper, with the final passes controlling thickness, width, edge condition and surface finish. Modern strip is supplied with thickness tolerances measured in microns, which allows consistent stamping, coiling and lamination in automated processes.
Grades and Properties
The strip is available in oxygen-free grades such as C10100 and C10200 for high-conductivity and brazing service, tough-pitch C11000 for general electrical work, phosphorus-deoxidized grades for formed and brazed parts, and copper-iron alloys such as C19200 for strength-critical components. Conductivity, temper and formability are selected for the final application.
| Grade | Conductivity | Typical Use |
|---|---|---|
| C10100 | 101% IACS | Brazed assemblies, electronics |
| C11000 | 101% IACS | General electrical strip |
| C19200 | 85 - 90% IACS | Lead frames, connectors |
| C12200 | About 85% IACS | Formed and brazed parts |
Applications
Typical uses are transformer strip and foil, motor windings, bus bars, heat sinks and heat spreaders, lead frames, terminals, flexible connectors and shielding. In transformers, thin copper strip reduces eddy-current losses and improves the packing factor of the winding.
Standards and Verification
Strip is covered by standards such as ASTM B152 for sheet and strip and B465 for alloy strip. Verify the grade, temper, thickness tolerance and surface condition on the certificate, and check the edge condition for coil-fed stamping lines.
