Mechanical Equipment & Tool Parts

Hairpin vs. Traditional Winding: Key Technical Differences in Modern Stator Manufacturing

https://www.gwinsys.com/hairpin-vs-traditional-winding.html

As electric motor technology advances—especially in the era of high-efficiency EV powertrains—manufacturers are increasingly shifting from conventional round-wire windings to hairpin winding technology. A modern hairpin stator production line enables highly automated, repeatable, and high-precision manufacturing, making hairpin stators a preferred solution for next-generation traction motors. Understanding the technical differences between hairpin winding and traditional winding methods helps illustrate why this new approach is rapidly becoming an industry standard.

1. Conductor Shape: Rectangular vs. Round Wire

Hairpin Winding

Uses rectangular (flat) copper wire, which provides superior slot fill and lower electrical resistance.
Larger cross-section improves current-carrying capability and reduces heat generation.
Consistent geometry allows automated forming, insertion, and welding.

Traditional Winding

Uses round copper wire wound continuously into the stator slots.
Slot fill factor is limited by the circular geometry.
Electrical efficiency is lower due to increased copper losses.

Technical Impact: Hairpin conductors significantly reduce copper loss, improving motor efficiency and thermal performance.

2. Manufacturing Process and Automation Level

Hairpin Winding

Highly compatible with automation.
Production steps—cutting, bending, insertion, twisting, laser welding, and insulation—are performed by a fully automated hairpin stator production line.
Ensures tight tolerances and consistent quality.

Traditional Winding

Relies more on manual or semi-automated coil winding processes.
Quality can vary with operator skill.
More difficult to guarantee precise conductor placement.

Technical Impact: Hairpin technology enables mass production with better repeatability, fewer defects, and higher efficiency.

3. Slot Fill Factor and Power Density

Hairpin Winding

Rectangular wire packs more efficiently, achieving up to 70–80% slot fill.
Better electromagnetic performance increases torque density and motor output.

Traditional Winding

Slot fill typically ranges 40–55% depending on wire diameter and winding method.
Lower fill results in reduced performance potential.

Technical Impact: Higher slot fill equals higher torque density, making hairpin stators ideal for EV traction motors.

4. End-Turn Geometry and Thermal Behavior

Hairpin Winding

Short, uniform end turns reduce copper usage and minimize I²R losses.
Excellent thermal conduction between conductors and stator core.

Traditional Winding

Long, irregular end turns reduce efficiency.
More hotspots due to uneven conductor distribution.

Technical Impact: Hairpin stators support higher continuous power and improved thermal stability.

5. Electrical Performance and NVH Characteristics

Hairpin Winding

Lower resistance and more uniform electromagnetic fields.
Reduced motor noise and vibration due to consistent geometry.

Traditional Winding

Higher AC losses, less predictable electromagnetic distribution.
NVH performance depends strongly on winding quality.

Technical Impact: Hairpin windings often deliver smoother, quieter motor operation—critical for EVs.

6. Flexibility and Application Scope

Hairpin Winding

Best suited for high-power, high-efficiency motors:

EV traction motors
Hybrid motors
High-performance industrial drives

Traditional Winding

More flexible for motors requiring:

Lower cost
Smaller scale
Irregular slot geometries

Technical Impact: Hairpin technology excels in applications where efficiency, density, and durability matter most.

Hairpin winding technology represents a major leap forward in electric motor manufacturing. With superior slot fill, lower losses, improved thermal characteristics, and high automation potential, hairpin stators deliver performance levels unmatched by traditional round-wire windings. A fully automated hairpin stator production line enables manufacturers to reduce labor costs, increase production throughput, and achieve consistent high-precision results—making it the ideal solution for next-generation electric motor production.

https://www.gwinsys.com/Hairpin-Stator-Assembly-Line.html

https://www.gwinsys.com/hairpin-vs-traditional-winding.html
Jieyun Intelligent Equipment (Suzhou) Co., Ltd.