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-- Winding systems --

Discrete Hairpin
  • Hairpin windings provide a very high copper slot fill factor in an eMachine resulting in higher power to weight ratio.

  • Our Wafios CNC Spring and Wire Forming System imports 3D geometries to manufacture the majority of hairpin & winding designs without the need to change tools as the basic tooling is independent of either wire cross-section or hairpin geometry.

  • The system includes all necessary tools for Hairpin manufacturing, also covering bus bars, phase leads, neutrals, star connections, and jumpers made of rectangular wire material. This includes aluminium and materials with novel coatings. The system can also be used to form battery busbars and inductors.
Continuous Hairpin
  • Continuous hairpin winding designs offer a reduced overall axial length of the eMachine couple with a reduction in the winding losses as the overhang of the windings from the stator lamination is reduced. When coupled with a reduction in the number of welds, as there are no open tails, the ability to manufacture continuous hairpins is essential for the DER Winding Centre of Excellence for trialling new technologies.

  • The NWS needle winding system is a six-spindle winding system capable of winding both
    • round (0.4mm to 3.5mm diameter) and
    • rectangular (1 x 5mm to 3 x 10mm cross-section) wires.

including aluminium and materials with novel coatings.

  • The production line is capable of the roll-up, compression of the double-layer wound mat, insertion, and expansion of the double-layer wound mat into the stator lamination stack.
Concentrated Winding
  • Concentrated windings provide a singular coil wound around a stator tooth or bobbin. This is a common method in the production of eMachine stators and the coils can be manufactured quickly. The result is a minimal coil overhang length from the stator lamination stack.

  • Therefore, it is natural that our NWS needle winding system has the capability to produce concentrated wound coils at wire diameters range of 0.7mm to 2mm.

  • Similar to all our other winding processes, it will be suitable for both copper and aluminium with novel insulation coatings.
Rotor Winding
  • Further rotor topologies are possible at the Winding Centre of Excellence, such as wound rotors.

  • The NWS needle winding system can directly wind the inside or outside of grooved rotors.

  • The various coil winding materials and coatings are suitable for this application with the addition of rotor mounting devices and basic holders.
Axial Coil Winding
  • In addition to conventional round and rectangular wires, newer coil winding technologies for novel motors can be trialled. Axial coil forming is possible on our Wafios CNC Spring and Wire Forming System.

  • Axial flux motors are becoming increasingly explored for automotive and aerospace applications due to their inherent higher torque and compact forms. The axial direction (rotational axis) of magnetic flux, rather than radially, results in a much shorter length of the rotor.

  • The Wafios equipment can wind bespoke inductor cores due to its flexible control systems.
Distributed Winding
  • Distributed windings form the bulk of eMachines now manufactured. The Aumann NWS needle winding equipment will be fitted with a manipular arm to allow the winding of distributed coils with up to 24 wires in hand. This will be able to provide bespoke distributed windings for prototypes or early phase production.


Remote Laser Welding System
  • Remote Laser Welding (RLW) for the joining of hairpins (both discrete and continuous) along with connection to busbars & terminals is a quick solution for welding joints.

  • The 6kW laser at the facility has image processing capability, to detect the positioning of components to be welded, and beam formation technology to produce a low-spatter weld.

  • RLW systems are flexible for the joining of dissimilar materials, such as copper and aluminium, which allows for process development for sustainable copper-free eMachines with aluminium windings.

-- Impregnation --

Trickle Impregnation
  • Following the winding and welding of the stator, impregnation is the next process flow in the manufacture of eMachines. Impregnation is a critical part of the creation of the stator as it provides the thermal pathway of heat from the windings to the laminations and cooling system. The impregnated stator has an improved mechanical structure to prevent vibrations of the windings in the lamination stack.

  • The trickle impregnation method is one of the most effective impregnation approaches, especially for high slot fill requirements. The stator is convection heated and held while being rotated and impregnated with a controlled flow rate of resin. In-process infrared heating during trickling is possible for correct temperature control.

  • The equipment at the Winding Centre of Excellence supports a wide range of impregnation resins and the dispensing of one or two-part resins with additional nozzles for a quick turnaround between trialling alternative resins. The equipment also provides adaptable fitting of stators of various sizes without the need for additional tooling costs.
Curing Ovens
  • The Winding Centre of Excellence facility hosts a range of curing ovens for applications such as final impregnation cure, oven curing of adhesive during magnet insertion & external mounting of permanent magnets (PM) on rotor hubs.

  • The availability of multiple curing ovens allows the optimisation of process parameters necessary for scaling to efficient high-volume production. The location of ovens within the facility allows for easy transfer between assembly processes.

  • The setup facilitates the evaluation of a variety of adhesives and resins for a range of eMachine technologies, from conventional interior PM motors to surface-mounted PM in a Halbach array.
Vacuum Impregnation
  • Impregnation repeatability is critical to provide eMachines with repeatable properties on Test. The Vacuum Pressure Impregnation system installed at the facility will provide an opportunity to develop VPI processes and test impregnation materials outside the standard production route, although using standard production equipment and staff with experience of using the technique.


Magnet Insertion
  • The capacity for the insertion of magnets at the Winding Centre of Excellence is a fundamental capability in the production of permanent magnet (PM) eMachines.

  • The magnet insertion stations at the facility allow for inserting either unmagnetized or magnetised magnets into laminated rotor stacks. A controlled and adjustable volume of adhesive can be applied to each of the slots before insertion. In-process heating control for the adhesive is monitored during gluing and application prior to insertion.

  • The facility is capable of utilising several types of PM materials, including NeFeB, SmCo, Alnico & Ferrites for trialling PM machines for high-temperature or more sustainable eMachine designs. This eMachine topology benefits from high-torque density and efficient operation common in the automotive sector.
  • Correct magnetisation is a critical area that defines the performance of a permanent magnet (PM) eMachine. The system flexibility at the Winding Centre of Excellence allows for the magnetisation of individual PMs for insertion into rotor slots or to fully magnetise magnets in a complete & assembled rotor.

  • This has the benefit of operators not needing to handle magnetised magnets which can translate to improved process development for high-volume production.

  • The magnetisation station is capable of magnetising several types of PM materials, including NeFeB, SmCo, Alnico & Ferrites at a maximum magnet size of 60 x 30 x 15 mm.

  • The magnetiser station can demagnetise individual magnetised magnets of any material. Additionally, it could be used to demagnetise complete rotors with the appropriate demagnetising fixture.


Electrical Properties
  • Static tests are used as an in-production and/or end-line test to confirm that the manufactured coils, stators and final eMachines comply with the expected values.

  • Electrical testing capability at the facility measures the coil, line-to-line, insulation, turn-to-turn, phase-to-phase, and phase-to-ground faults insulation resistance.

  • These tests are fundamental to eMachine production for verification & validation of the manufactured eMachine system.

Get in Touch:

Dr David Simkin

Head of WMG Winding Centre of Excellence, Principal Engineer, Power Electronics and eMachine group

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