Powerful but lightweight electric motors are seeing an increasing demand in the automotive industry. Extremely high torque in-wheel electric motors from PMW are helping to meet the growing requirement for powerful motors in electric and hybrid vehicles. In addition, PMW’s brushless DC electric motors are powering hydraulic and air compressor pumps and simulation robots in vehicle design and test applications. They are also being used in electric power-assisted steering systems.

Application: a steering robot for vehicle testing

A brushless DC motor designed by PMW for use in dynamic vehicle testing is part of a steering robot developed by Anthony Best Dynamics. The system helps provide a repeatable test environment for quantitative testing of road vehicles on the track.
The compact dimensions of the conventional internal rotor design of the motor enable the assembly to be mounted behind the steering wheel, allowing normal driver operation between tests.


During the design process the two companies’ engineering teams worked closely together to ensure the exacting specifications of the motor package were met. “PMW took a complex design, generated production drawings and manufactured it to meet all our performance requirements,” said Colin Martin, design director at Anthony Best Dynamics. “This is all the more appreciated as we only need the motor in fairly low volumes.”


Application: in-wheel motors for a hydrogen car

A key feature of the Rasa hydrogen fuel cell car developed by Riversimple is its four in-wheel electric motors, which were developed by PMW. These thin, powerful pancake motors had to meet a number of demanding requirements, including the need to have an integral mount for the brake disc.


Further constraints were the use of conventional, externally mounted disc callipers, a low target weight and the need for the whole package to fit within a 15 inch wheel rim. The XR32-11 in-wheel motors produced by PMW allow the car to use regenerative braking, recapturing over 50% of the kinetic energy, and using a bank of supercapacitors in the front of the car to store the electrical power generated. “PMW worked closely with us on the design of the motor, which meets all the required torque, speed and thermal requirements. The quality of manufacture of the motors is also excellent, and they have performed faultlessly during testing,” said Martin Stevens, electronic systems engineer at Riversimple.

The brushless DC motors help to keep the weight of the vehicle down, as they deliver unparalleled performance for their size, with each capable of producing a peak torque as high as 160 Nm while weighing only 17 kg.






PMW Dynamics