Case Study
Switchtrack Braiding: Litz wire
Project challenges
- Exploring the machine's capabilities
- Determine the manufacturability of braided Litz wire
- Develop samples to be used in off-the-shelf motors
Business challenge
Process Innovation
Sector
Electrification
Technology or capability
Product Design
Process Design
Using the MTC’s switch-track braiding machine, samples of braided Litz wire were produced to explore the machine’s capabilities and understand the manufacturability of braided Litz wire. The samples proved effective when inserted into an off-the-shelf motor and demonstrate scope for further development.
Using Litz wire allows us to reduce electrical losses due to skin effect and proximity effect. The flexibility of the machine also allows us to deliver bespoke braided Litz wire constructions optimised to our customer’s requirements.
Will Pollitt, Technology Manager, MTC
The Challenge
Litz wire is most commonly produced twisted, with multiple configurations of enamelled wire within it. Using Litz wire aims to reduce the ‘Skin effect’ caused by current distribution within the conductor, where it increases the resistance and incurs losses. Litz wire is also subject to the ‘Proximity effect’ due to multiple strands of conductive wire being so close together.
Currently the supply of Litz wire is on a long lead time, and often manufactured outside of the UK. The MTC wanted to understand if the switch-track braiding machine can produce suitable braided Litz wire to service a functioning motor and improve its performance.
The Outcome
- The motor wound with MTC’s Litz wire reached double the top speed when compared with the off-the-shelf motor
- Compression of the Litz wire into a defined profile improved the ability of the wire to be applied onto the motor
- Both copper and aluminium wire are effective materials for braided Litz wire
- Litz wire can be produced rapidly on the MTC’s switchtrack braiding machine, which has been tested on single core wire sizes up to 3.15mm
MTC's Solution
- The MTC produced a variety of Litz wire using different sized wires in order to verify what sizes would work on the switchtrack braiding machine
- Manipulating the profile of the braid was done through a design of experiments investigating the effect of compression on the braid
- Selected samples of Litz wire were wound onto an off-the-shelf drone motor, where speed, current and voltage were measured parameters and compared to the baseline performance
Benefits to the client
- Demonstrated application of MTC produced braided Litz wire in a working drone motor
- Identified braiding parameters suitable for manufacturing Litz wire, and gained further understanding of switch track braiding machine capabilities for future development projects
- Proven initial testing of aluminium Litz wire, with demonstrated performance when applied to an off-the-shelf motor
The advancements achieved through the innovative braiding of Litz wire represent a paradigm shift in electrical engineering. These breakthroughs are poised to deliver substantial benefits to the Automotive and Formula 1 sector, enhancing performance, efficiency, and reliability in high-demand applications
Danny McGee, Associate Director, MTC
