At the 2013 Geneva Motor Show, Land Rover unveiled a range of new electric Defender vehicles which are directly powered by an electric motor and drive system developed and built by Nidec SR Drives Ltd.

In the electric research vehicles, the standard diesel engine and gearbox of the Land Rover 110 Defender has been replaced by an SR Drive® 70kW (94bhp) switched reluctance (SR) electric motor, twinned with a 300-volt lithium-ion battery with a capacity of 27kWh, giving a range of more than 50 miles. It has a top speed of 70mph and, in typical low speed off-road use, can run for up to eight hours before recharging.

The switched reluctance technology developed by Nidec is exceptionally well-suited to the Defender’s arduous all-terrain traction needs, being able to deliver full-rated power over a wide speed range. The electric vehicles (EVs) retain the Defender’s four-wheel drive system and differential lock. But, because the SR motor delivers 330Nm of torque from standstill, there’s no need for gear shifting and the transmission comprises a single speed, 2.7:1 reduction gearbox, combined with the existing Defender’s 4-wheel drive system.

Harrogate-based Nidec SR Drives Ltd has pioneered the development, application and commercialisation of switched reluctance technology for more than 30 years, and is recognised as world leader in the field. At its research and manufacturing facility, the company developed the drive technology employed on the electric research vehicles, and built the motor and power electronics for the seven Defender models shown in Geneva.

The smooth, low-speed capability of the SR electric powertrain makes the electric Defender especially well-suited to climbing and descending inclines without causing unnecessary damage to ground surfaces. The vehicle has been tested in extreme and environmentally sensitive conditions; trials included pulling a 12-tonne ‘road train’ up a 13% gradient, and wading through water up to a depth of 800mm. deep. The absence of air intake or exhaust system allows a 300mm increase in wading depth compared with a standard Defender.

“We are delighted to have worked with Land Rover on this exciting development”, said Dr. Roy Blake, managing director of Nidec SR Drives: “It was a great opportunity for us to transfer our proven traction technology from heavy-duty mining and construction vehicles to smaller road-going applications. The marriage of our rugged high-performance technology with the Defender vehicle is an excellent pairing and aligns well with plans by Nidec Corporation to place SR Drive® technology at the heart of its EV traction developments.”

Switched reluctance motors deliver high-performance without the use of rare-earth materials such as neodymium and dysprosium. Materials that are fully-recyclable at the end of life, such as copper, steel and aluminium, are used in the manufacture of an SR Drive® motor; an important consideration for automotive applications.


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