Electrification of European farm implements has sparked intense interest, competition and innovation in electric motor technology. That initiative is now getting a jolt from Formula 1 car designer Ian Foley.
Foley was a key engineer on the Lotus, Benetton and Williams F1 teams. He played the lead role in developing Williams F1 hybrid petroleum/electricity system. The resulting hybrid flywheel arrangement went on to winning success in endurance racing with Porsche and Audi.
Foley explained the revolutionary technology in an email interview.
“In the early 2000s Equipmake (his company) was doing research into electric motors and flywheels because we knew F1 powertrains were going to go hybrid. The FIA was preparing to mandate ultra-capacitors for this technology. But we proposed the idea of a flywheel, which they liked.
“We were contacted by several F1 teams who were keen to develop the technology further. Because we were a start-up, that was a bit overwhelming. We didn’t want to bite off more than we could chew, so we decided to work with one highly respected team, and that was Williams. The resulting hybrid flywheel system went on to be used to great success by Porsche and Audi in endurance racing.”
His F1 re-generative braking system uses flywheel/generators at the wheels to harvest rotating energy and store it under hard braking. That energy is then released to the driver the instant he accelerates again. Obviously, these generator/motor units had to be small, light and able to take the heat and abuse. He accomplished this feat for the Williams team, with the tiny flywheels spinning at 50,000 to 100,000 r.p.m.
“But there were applications for the flywheel technology outside motorsport so Williams Hybrid Power was formed, with me as managing director. Successful though that was, the yearning to be my own boss never really left. The high-speed flywheel developed for the Williams program was effectively a composite electric motor, so I revived Equipmake with the aim of using some of the expertise I’d developed in electrification and applying it to a new design of motor.”
The APM spoke architecture offers high power density, light weight and compact packaging. The spoke name came naturally because the device looks like a spoke. The company’s APM motors are believed to be among the most power-dense in production in the word.
Farming was part of the business plan when Foley established a new Equipmake factory and research facility in Snetterton, England, last year. He was finally ready to commercialize the technologies he had developed in F1.
“Our electric motors are extremely compact and lightweight, yet powerful. This has multiple benefits. One of the most obvious and immediate is how they can play a huge role in improving the payload of a farm vehicle. Electric motors, and e-powertrains in general, require less maintenance compared to traditional diesel machinery. Running costs are lower and lifecycles longer. Electrification makes so much sense.”
Foley sees a huge potential for putting his advanced electric motors in loaders, combines, sprayers, tractors, trucks, grain elevators and other farm-related machinery. Electrified farm vehicles offer increased payload and productivity with zero missions and lower operating costs than traditional fossil fuel vehicles.
The spoke devices are permanent magnet motors that use a spoke architecture, so-called because the magnets are arranged like the spokes of a wheel. The spokes are a significant cooling component. If an electric motor is kept cool, it produces more power and torque, and uses less expensive magnet materials. Plus it can be built with conventional manufacturing methods, making it more cost-effective.
Foley said, “The same factors in racing are just as relevant to the world of agriculture. We have high power density and light weight combined with an extremely compact package that includes integrated components such as the inverter and gearbox.”
Equipmake offers two compact, power-dense motors for agricultural applications, both of which use the spoke architecture to maximize cooling.
The smaller APM 120 has peak power of 125kW (168 horsepower) at 12,000 r.p.m., with continuous power of 75kW (100 h.p.) and peak torque of 130Nm (86 foot pounds). Weighing just 14 kilograms (31 pounds), it has a power density just under 9 kW per kg. With an integrated gearbox, it measures 200 millimetres (eight inches) in length and 170mm (seven inches) in diameter.
The larger APM200 weighs 49 kg (108 lb.), can run at 10,000 r.p.m. and has peak power of 220 kW (295 hp) and peak torque of 450 Nm (332 foot lb.) It has a power density of more than 5kW per kg. With an integrated gearbox, it measures just 247 mm (10 inches) in length and 318 mm (13 inches) in diameter.
The motors incorporate an integral 5.5:1 epicyclic gearbox so the output shaft of the gearbox can be connected directly to a machine. Both motors can be specified with or without an integrated gearbox and can be mounted horizontally or vertically. Equipmake also makes all supporting power control electronics in-house, including a high-performance inverter incorporating the latest silicon carbide diode technology to improve power capability and enable the inverter to run at high switching frequencies.
Cooling is key to electric motor performance. Cooler magnets run longer at maximum power. Cost saving is helped by using cheaper grade neodymium iron boron (NdFeB) magnets.