Hitachi Construction Machinery Launches EH3500AC-3 and EH4000AC-3 Rigid-Frame Haul Trucks
With AC-drive system and drive control software
Hitachi Construction Machinery – Americas has announced the launch of two rigid-frame haul truck models designed for use in large-scale mining operations – the EH3500AC-3 (nominal payload with standard equipment of 200 tons, target gross machine operating weight of 709,888 pounds), and the EH4000AC-3 (nominal payload with standard equipment of 243.6 tons, target gross machine operating weight of 846,575 pounds).
The release of these two rigid-frame haul truck models completes the lineup for the EH AC-3 series of haulers equipped with an AC-drive system. Hitachi couples the AC-drive system, which has a high load–responsive IGBT inverter, with drive control software to achieve a system that excels in controlling travel motor speed and torque. Whether taking off from a standstill, ascending grades or performing steering maneuvers, the system delivers an optimal, individual amount of power to each of the travel motors for smooth, quick operation.
In addition to adding various sensors that detect vehicle motion, this is the first time in this class of machinery that models employ the Hitachi Drive Control System, which aims to achieve higher drive control performance by reducing tire slippage on acceleration and tire lock-up during braking, and preventing chassis oscillation in a front-rear direction and tire skid while steering. Consequently, the trucks boast strong and steady travel performance that ensures more stable jobsite haul-cycle times, which contributes to higher productivity.
These models also feature powerful electric brakes that are activated during downhill driving. Since these trucks do not require the use of mechanical brakes during normal driving, not only is deceleration smoother but maintenance for the mechanical brakes is required less frequently.
The mainframe’s structural design, including the cab support, is improved and fortified based on operating information Hitachi gathered on conventional models being used around the world.
The company added a temperature sensor to the bearing area of the alternator and drive motor, which are the main components of the AC-drive system. An alarm sounds when the sensor detects abnormal heat emission and restricts driving operations to prevent sudden damage to the machine.
Improvements were made to the nominal payload measurement system to increase the reliability of production volume measurements at mining sites. Measurement errors have been reduced by reflecting changes in fuel weight within the fuel tank into the nominal payload.
The evacuator exhaust valve for the engine suction filter and electric grease pump are among the new features added to further improve daily maintenance.
