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Independent Test Results
Testing performed by Revolutionary
Engineering, Inc.
Symetron™ Dynamometer
Tests
Raser’s recent
advancements in AC induction motor
and controller technology are so
significant that many leading
manufacturers and engineers have
requested an opportunity for
validation and verification.
Naturally, dramatic gains in
performance of this magnitude are
met with skepticism. In order to
provide an opportunity for
validation of the technology, Raser
provides opportunities for
performance evaluation on
dynamometers at independent
facilities.
Due to the very high torque density
and extended speed range of a
Symetron enhanced motors and
controllers, the number of
facilities with adequate testing
capabilities is somewhat limited.
This test was performed at
Revolutionary Engineering Inc. in
Detroit, an engineering firm that
designs, builds and installs high
performance dynamometer test
facilities.
In this test, a Symetron P2 AC
induction pancake motor was driven
by a controller using proprietary
Symetron technology.
The test utilized a four-quadrant
dynamometer test stand that provides
the high torque load capacity needed
to drive a small Symetron motor.
The two most significant performance
characteristics measured in this
test showed a dramatic improvement
in both peak torque and continuous
torque.
The Symetron P2 AC induction pancake
motor being tested here is 8 inches
by 12.5 inches in diameter. This is
a common size used in many hybrid
vehicles and integrated drive trains
today. It weighs just 67 kilograms
or 147 lbs.
The Peak torque was measured for a
duration of 30 seconds at over 420
ft lbs on numerous repeated runs.
For the sake of a simple comparison,
this P2 motor is about the same size
as the permanent magnet motor found
in the current Toyota Prius hybrid,
yet the Symetron AC induction motor
tested here, is delivering over 100
ft lbs MORE torque than the Prius
permanent magnet motor which
delivers approximately 290 ft lbs of
peak torque.
Symetron motors can be driven by
conventional controllers, however
this test revealed that when a
Symetron motor is driven by a
controller using Symetron
technology, a dramatic improvement
in torque and efficiency is
achieved.
The continuous torque was measured
at 132 ft lbs or 179 Newton Meters
with peak efficiency of 92%. Temperature
was thermally stabilized for this
measurement at over 60 seconds of
continuous operation.
In this test simple air-cooling was
used. Though this continuous torque
rating is already comparable or
superior to high-performance liquid
cooled motors, it is reasonable to
assume that the continuous torque
rating should increase even higher
when tested using liquid cooling
techniques. The air-cooled Symetron
motor is performing here with the
continuous torque rating comparable
to liquid cooled permanent magnet
motors used in hybrid vehicles such
as the Toyota Prius.
Power is calculated at 179 kilowatts
at 3000 rpm delivering 240
horsepower. The effective torque per
volumetric liter is 35 Newton meters
per liter. This is an important
characteristic for application in
space and weight limited
applications such as hybrid
vehicles.
In summary, this dynamometer test
demonstrates that an AC induction
motor can achieve more peak torque
than a similar sized permanent
magnet motor.
A summary of the performance results
for this dynamometer test are
available at Raser Technologies’
website.
High performance is not the only
critical criteria in choosing a
technology to manufacture,
Manufacturability and cost of
materials are also extremely
important.
The torque density improvements
demonstrated here indicate that a
given motor’s rated size can be
reduced significantly while
maintaining or even improving rated
efficiency and torque in controller
driven applications.
Motors manufactured using Symetron
design and technology utilize the
same low cost materials, namely
copper and iron, used in a building
standard AC induction motors.
Symetron enhanced motors can be
built using the same winding
machines and processes used by
conventional motors.
This suggests a significant
opportunity to reduce manufacturing
costs and capture significant market
advantages.
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