Machine Design

Forklift motor lets eMotorcycle take the checkered flag


Virginia Tech University,

Engineering students at Virginia Tech University designed an electric motorcycle that ran in the TTXGP, a series of 20-mile races. The motorcycle, dubbed the VT Bolt, competed in the 75 class, in which bikes are limited to a 7.5-kW-hr battery pack. The bike took first place in all three of its races, consistently hitting top speeds over 100 mph.

The VT team worked with engineers from Kollmorgen, Radford, Va., the company that supplied the motor, a permanentmagnet, low-voltage AKM 74, and the controller, an ACS80XL 80V Gen6. The motor was modified to accept a motorcycle sprocket and was outfitted with a custom side bearing that let it withstand higher-than-normal loads exerted on the shaft by the chain. The motor was also rewound to operate on the battery-pack’s relatively low voltage. The controller, usually used with motors having a maximum of 54 hp (40 kW), was “delimited” to let it control motors with up to 73 hp (57.6 kW). This let the controller and motor better handle the short-duty cycles and power demands of TTXGP races. The controller was also modified to control speed, torque, and regenerative braking. The drive usually controls traction in 4 to 5-ton fork lifts. Both the motor and controller are sealed to IP68 levels, so they can withstand vibrations common in race cars.

The VT Bolt won all three of its races, making it this year’s North American TTX75 Cup winner.


© 2012 Penton Media, Inc.

TAGS: Energy Archive
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