The TT Zero event, established in 2010, is a race for motorcycles powered without the use of carbon-based fuels.
The Victory Racing team’s prototype bikes, ridden by “General” Lee Johnston and road racer and television presenter Guy Martin, took third and fourth spot respectively in the all-electric race.
The prototype electric motorbikes, powered by Parker Hannifin’s Global Vehicle Motor (GVM) PMAC electric motors, weigh just 220 kilograms each, and are capable of average lap speeds approaching 120mph.
Despite measuring just eight inches in diameter and five inches long, the GVM motor can deliver 175 horsepower, and has an efficiency of 97 per cent.
To develop a device that could generate a large amount of torque, and therefore power, for its size, the company designed a 12 pole motor, referring to the number of sets of North-South electromagnetic poles formed by the magnetic windings. The more poles a motor has, the greater its torque will be.
“Victory actually had the power turned down on the Zero bikes,” said Kevin Holloway, the US strategic account manager for vehicle electrification at Parker Hannifin. “The motor was capable of more power, but there’s only so much on-board energy that the motorcycle has; therefore you have to ration the amount of energy in order to complete the course,” he said.
The electromagnetic windings used in the stator also incorporate very short end turns, to increase the efficiency of the motor by reducing heat loss, said Holloway. “These end turns are where a large amount of heat is lost in the winding, leading to inefficiency,” he said.
“The short end turn design greatly reduces the winding resistance and in several types of vehicles has led to a 30 per cent increase in range – all with the same size battery pack.”
That is particularly significant since batteries are still the most expensive part of electric and hybrid vehicles, he added.
The GVM motors also use a water-based internal cooling system, said Holloway. Water extracts more heat than oil, and water systems are easier to deal with than an oil-cooling loop, he said.
“Our system is designed to reside within the motor diameter, rather than creating a jacket around it,” said Holloway. “The smaller volume achieved means that the motor has a higher power density.”
Alongside electric motorcycles, the technology is already being used in hybrid vehicles. The high power produced by the motor allows the on-board combustion engine to be used for battery charging, resulting in a smaller engine and greater energy efficiency, said Andy Parker-Bates, UK technology and market development manager for automation products at Parker.
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