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els completes the lineup for the EH AC-3 series of haulers

equipped with an AC-drive system.

Along with the company’s ultra-large hydraulic excava-

tors, for which Hitachi boasts a high market share, Hitachi

plans to supply these rigid haul truck models to contribute

to the improvement of productivity at mines around the

world.

1. Increased mobility and productivity

Hitachi couples the AC-drive system, which has a high

load-responsive IGBT inverter, with drive control software

that was jointly developed with other Hitachi Group com-

panies, 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 vehi-

cle motion, this is the first time in this class of machinery

that models employ the Hitachi Drive Control System.

This 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 two models also feature powerful electric

brakes that are activated during downhill driving.

Since these trucks do not require the use of mechani-

cal brakes during normal driving, not only is deceleration

smoother but maintenance for the mechanical brakes is

required less frequently.

2. Increased Operator Features

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 safe-

ty.

Thanks to a powerful electric brake, the haulers can be

normally operated using two pedals, one for acceleration

and one for the brakes. Easier operability alleviates opera-

tor fatigue.

Hitachi located the levers and switches for operating

the body in the center console, making it possible to oper-

ate the body with one hand.

3. Increased reliability and safety

The mainframe’s structural design, including the cab sup-

port, is improved and fortified based on operating infor-

mation 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 produc-

tion volume measurements at mining sites. Measurement

errors have been reduced by reflecting changes in fuel

weight within the fuel tank into the nominal payload.

ROPS and FOPS are built into every truck cab as a

standard safety requirement to withstand the impact of

falling objects or a truck rollover.

Other standard safety features include:

• two mirrors with front and rear view cameras to

provide extensive truck perimeter visibility,

• ample width truck access stairways

• four engine stop switches located outside the cab

to allow the operator to turn off the engine in an

emergency situation during maintenance.

In addition, the wide cab features ample foot space to

improve the operating environment.

The

Peripheral Vision Support System

feature pro-

vides another view to support the operator.

4. Maintenance and serviceability

The evacuator exhaust valve for the engine suction filter

and electric grease pump are among the new features

added to further improve daily maintenance.

Other standard features for maintenance include a

trailing arm front suspension that permits strut removal

without tyre removal, a centralized auto-grease system

accessible from the ground, a battery and relay box lo-

cated in the front bumper for easy access, and a mainte-

nance deck in the rear of the cab.

Outside of North America, Hitachi is now

offering customers the option of choosing be-

tween the standard feature Cummins Inc. en-

gine and one by MTU Friedrichshafen GmbH.

New technology enhances

safety of Hitachi mining

equipment

Hitachi Construction Machinery Co., Ltd (HCM)

has obtained the licence for camera image

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.

Page 58

Contractors World International Vol 6 No 4

What’s New In Plant & Equipment