MOTORS
MERCEDES-BENZ ACQUIRES YASA
Oxford-based YASA was founded
to commercialise an innovative new
approach to the design of electric
motors. The power density (kW/kg)
of the company’s axial- ux motors
has improved at a rate of 15% yearon
year. Today, YASA’s design is said
to o er e ciencies over 96%.
YASA says that its axial- ux
electric motors are unique in that
they feature a proprietary ‘Yokeless
And Segmented Armature’ (YASA),
whereby the armature windings
consist of separate segments ideally
suited to mass manufacture with
minimal application engineering.
In addition, YASA’s direct oil
cooling solution helps the
motors achieve higher
continuous power.
These advantages, among others,
prompted Mercedes-Benz to acquire
the company in July 2021.
YASA CEO Chris Harris said:
“The YASA team, all 250 of us, will
continue to operate from our HQ
and production facility in Oxford, and
our innovation facility in Welshpool.
We’ll provide electric motors for
Mercedes-Benz’s AMG.EA electriconly
platform, while acting as an
innovation partner pioneering new
electric-drive technology for the
wider group. We’ll also continue to
supply our existing automotive
supercar customers.”
Mercedes-Benz is planning
to assemble YASA motors
at its Berlin drivetrain
components factory.
is radial and the conductors are axial,
whereas in an axial- ux machine, the airgap
ux is axial and the conductors are
radial.”
Ferretti says that a yokeless axial- ux
machine allows the use of a double rotor.
“Since the PM machine output torque is
proportional to the e ective air-gap area
for a constant electrical and magnetic
loading, the axial- ux PM machine with
double air-gap rotor achieves a higher
torque-to-weight ratio. Furthermore,
in axial- ux machines, the magnets are
located further away from the central axis,
resulting in a larger lever on the central
axis and thus producing more torque.”
RAMPING UP
Magnax, which was founded in 2015
and has its headquarters in Kortrijk,
Belgium, raised €16 million in funding at
the end of 2020 and has just expanded
its pilot line for axial- ux motors. The
company says prototyping and DfM
(design for manufacture) in collaboration
with customers has resulted in motor
technology that delivers three to ve
times more power density in comparison
with traditional alternatives.
Among those specialising in this
technology is Bicester-based Saietta
Group, which o ers its Axial Flux
Technology (AFT) e-motors. Saietta’s
motors can integrate into lightweight zeroemissions
vehicles, including scooters,
rickshaws and micro-cars (pictured above
left). Saietta Group plc is now listed on the
London Stock Exchange’s AIM market, and
has a market capitalisation of about £102.1
million at the issue price.
According to Saietta,
a ordable electric
propulsion and battery
systems are key to reducing EV
cost and enabling widespread adoption.
This progression is an essential step for
many emerging economies and cities
gripped by chronic air pollution, especially
in Asia, where the most common forms
of transport are lightweight wheeled
vehicles.
“Our AFT motors are compact and
light, while delivering high torque and
e ciency at low voltage,” says Wicher
Kist, chief
executive of
Saietta Group. “This
enables vehicle manufacturers
to reduce the required battery
size for a given range and, in turn, use
a lower quantity of rare materials in
their construction. Designed for highly
automated production, our AFT motors
are intended to make lightweight EV
adoption more viable by reducing total
vehicle cost.”
With the AFT in low-volume
production, Saietta’s engineering team is
now nalising the development of a new,
high-voltage variant intended for highperformance
vehicles, while a further
innovation is a product for in-wheel
applications. Moving the powertrain fully
into the wheels creates a at oor with
minimal intrusion into the rectangular
platform. This concept maximises the
usable space above the chassis for the
primary purpose of the vehicle.
“Although the motor industry
has focused on electri cation of the
passenger car segment, Saietta has
taken a contrarian view and concentrated
on high-volume, high-growth markets,”
says Kist. “We believe we are uniquely
positioned to disrupt the Asian
lightweight motorbike market, which
is expected to dominate demand for
motorcycles; global annual sales of which
are independently forecast to reach circa
100 million by 2030. Around 40% of this
number will likely be electric.”
Above: Saietta
axial ux motor in
assembly
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