Hitachi Construction Machinery Co. Ltd. launched two rigid dump truck models designed for use in large-scale mining operations anywhere in the world – the 180-ton payload class EH3500AC-3 (nominal payload with standard equipment of 181 tons, target gross machine operating weight of 322,000 kg), and the 220-ton payload class EH4000AC-3 (nominal payload with standard equipment of 221tons, target gross machine operating weight of 384,000 kg).
The two rigid dump truck models are equipped with an AC drive system that was developed with Hitachi Group technologies employed in conventional models. The improved AC drive system features various sensors that provide information on drive conditions. The result is a drive-control system that reduces tire slippage on acceleration and tire lock-up during braking, and prevents chassis oscillation in a front-rear direction and tire skid while steering.
In addition, to satisfy the request of customers worldwide, the company offers a choice between engines from two different companies. This option will also be made available for the EH5000AC-3 rigid dump truck, which was launched in February 2013.
The release of these two rigid dump truck models completes the lineup for the EH AC-3 series of dump trucks equipped with an AC drive system. Main features include:
High Mobility and Productivity – The company coupled the AC drive system, which has a high load-responsive IGBT inverter, with drive control software that was jointly developed with other Hitachi Group companies, 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 the company has employed 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. This ensures more stable jobsite haul-cycle times which contributes to higher productivity.
These two models also boast powerful electric brakes that are activated during downhill driving. Since this dump truck does 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.
High Operability – In the wide-berth cab, which is capable of housing two full-size seats, a large LCD display is located at the base of the handle. The display is in clear view and quickly provides the operator with information and warnings on drive operations such as traveling speed, engine turnover, and hauling performance. In addition, the multilingual display allows users to view information and warnings in their own language, thereby contributing to improved serviceability and safety.
Thanks to a powerful electric brake, the dump trucks can be normally operated using two pedals, one for acceleration and one for the brakes. Easier operability alleviates operator fatigue.
High Reliability and Safety – The mainframe's structural design, including the cab support, is improved and fortified based on operating information the company gathered on conventional models being used around the world.
A temperature sensor was added 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. Measurement errors have been reduced by reflecting changes in fuel weight within the fuel tank into the nominal payload. In this fashion, the company is working to further improve the reliability of production volume measurements at mining sites.
Hitachi Construction Machinery, hitachiconstruction.com