Technology
E-Motor

Form Litz Winding

Most innovative winding technology for unprecedented efficiency in e-motors and entire powertrain systems
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25%
less power loss in e-motors
20%
higher continuous power
Smaller & lighter
e-motors and reduced overall system packaging
Technology leadership
with 5 years of development progress
The power of Form Litz Winding:
The next step in electric motor winding technology
Form Litz Winding surpasses the performance of current technologies on the market. Studies have shown that the hofer powertrain Form Litz Winding technology combines the benefits of other technologies and simultaneously breaks their boundaries.
Increased efficiency
Form Litz Winding (FLW) significantly reduces the losses inside the electric motor while also reducing its size and weight, increasing the driving range of electric vehicles.
Higher sustained performance
FLW has a proven better heat transfer than other winding technologies, allowing the e-motor to maintain constant high power. FLW reduces the gap between continuous and peak power.
Optimization on system level
Reduced heat generation, higher efficiency and increased electric motor performance have numerous benefits and savings for the complete system.
Application Areas
Motor Sport Vehicles
Delivers more energy to the road with reduced weight, maximum efficiency, and consistent performance
High-Performance Cars
Provides top-notch driving experience with extended driving range
Commercial Vehicle
Wide electrification of buses and trucks for more efficiency and CO2 reduction in light and heavy duty sectors
eVTOL
Allows to realize ultralight-weight, high-safety solutions for electric Vertical Take-Off and Landing applications

About the technology

What is Form Litz Winding

Form Litz Wire consists of parallel wires packed into a highly compact form winding found in the stator of high power density electric motors. Its better heat transfer goes beyond the potential of current winding solutions, which is needed in modern designs and even more so in future automotive powertrain solutions. This is the best solution for high-power applications since its copper filling density reaches up to 65%, making it comparable to Hairpin winding. At the same time, its high-frequency performance is as good as pull-ins.

Mitigation of proximity and skin effects

The proximity effect is one of those power loss factors that is often largely overlooked. However, this phenomenon can be several times more significant than the skin effect since it causes other nearby conductors' non-uniform distribution of AC current. It is one of the most critical factors in controlling losses within the winding solutions. Another notable effect is the so-called "skin effect." When current flows through a single wire conductor, the current is increasingly pushed toward the surface "skin" of the conductor as frequency increases—using Litz Wire winding helps to reduce the skin effects significantly. The current flows through nearly the entire cross-section of each wire, thus minimizing AC resistance and heat losses.

Reduction of footprint and weight

Developing e-motors, stators, and rotors requires a high use of rare earth metals, among other materials. Using hofer powertrain Form Litz Winding technology helps considerably reduces these amounts. Reduced material usage in the entire housing minimizes its overall package size and weight.

Effortless industrialization

No complex tools or time-consuming and error-prone manual production steps are required in the manufacturing process since the technology can use the existing Hairpon equipment. One of the benefits here is the ability to achieve high quality with short cycle times. On top of that, industrialization proves highly scalable with high reproducibility and smaller manufacturing tolerances.

Extended driving range up to 2%

Depending on the e-motor, the solution can significantly increase the driving range of batteries while improving their life and durability. Both energy consumption and energy losses are reduced compared to solutions with Hairpin winding.

Advantages of Form Litz Winding

  • Meets increasing demand for innovative quality technology in e-motors
  • High cost reduction potentials in series production
  • High continuous power output for an extended driving range
  • Decrease of eddy current losses especially with increased current frequency
  • Quick incorporation into all types of e-motors
  • Reduced input of materials including rare earth metals

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