‘It has to be 25,000rpm’
Triumph’s new electric bike motor has 4.8 times the power-to-weight ratio of an S1000RR
This is what Triumph’s new electric Speed Triple will look like. It’s not a running prototype yet but with the chassis, suspension, brakes, charging components, battery and motor all in one piece, and the battery configured to give the right centre of gravity, Triumph say Phase 3 of the TE-1 project is complete. Over the next six months, the motor and electronics will be tuned on the dyno to turn the bike into a rideable prototype. Triumph are still working to their original claims: 220kg; 174bhp; 120 mile range and a 0-80% recharge in 20 minutes – but have added that the motor’s peak power density is 13kw/kg. This is 4.8 times greater than an S1000RR engine. Triumph say the continuous power density is 9kw/kg, which equates to 120bhp. ‘Those figures are very impressive,’ says Ian Goodman, a technical expert for the Electric Road Racing Association. ‘If true it’s an industry step change – some Zeros only have peak power densities of 6 or 7kw/kg. Heat is the biggest issue with motors though so my conclusion is, yes, Triumph’s claimed power density is possible, but the motor will be extremely expensive and there are lots of ways it could be compromised.’ Phil Eagleton, CEO of Voltsport.co.uk, agrees: ‘My guess is that it’s a 25,000rpm motor to achieve that [power density]. But it’s all about cooling. To make motors lighter, engineers take metal out of them, but it’s the metal that helps the heat get out, so they can’t do the continuous power unless they’ve got oil cooling around the stator windings, like Yuasa.’ The Triumph has three radiators, two look like they contain water. The middle one might be an oil cooler though. Besides the big power, another clever aspect of the motor is it’s combined with the inverter (the device which turns direct current from the battery into the alternating current needed by the motor). By merging the two for Triumph, British company Integral Powertrains have saved a lot of space, while maintaining that potential for massive power. The battery has been developed by Williams Advanced Engineering, an off-shoot of the F1 team. Contained in a carbon fibre shell, it has integrated cooling, though Triumph do not say whether this is by oil or water. All that Dyrr Ardash, Head of Strategic Partnerships at WAE, says is: ‘Because we have designed the battery from the ground-up, design has not been compromised and we have been able to push the boundaries of current technology.’