Hitachi’s EH3500 Haul Truck is AC-Powered

Hitachi Mining, a division of Hitachi Construction Machinery, claims it has set the standard in AC drive haul truck technology with the introduction of its EH3500AC rigid dump truck. The EH3500AC is powered by a Cummins 16-cylinder, QSK50 EPA Tier II compliant turbo diesel, developing 1,491 kW (3,500 hp) at 1,900 rpm and driving through axle-mounted Hitachi AC traction drives. Fully loaded, the EH3500 weighs 500 mt with a payload of more than 360 mt. Top speed is claimed to be more than 55 km/h. According to Hitachi, AC drives offer 6%-7% higher efficiency (averaged over the duty cycle) than DC drives of comparable size, allowing faster travel speeds while reducing fuel consumption. Using the same drive concept as a diesel electric locomotive, the EH3500 AC’s diesel engine powers an AC alternator. Constant-voltage DC power from this alternator is transformed by an inverter into variable frequency AC, which in turn supplies AC electric motors mounted in the truck’s rear axle. Output frequency and voltage of the inverters are controlled to provide precise motor torque and speed. For braking by retardation, the inverters generate electric power by slowing down the motors. Braking choppers, connected to the inverters, channel that power into a resistor grid that continuously dissipates the energy until the truck reaches standstill.

www.hitachi-c-m.com

As featured in Womp 08 Vol 2 - www.womp-int.com