OM5015 03/01 Specifications - Section 5 Component Descriptions Page 5-1 MAJOR COMPONENT DESCRIPTION Truck And Engine Operator’s Cab The 930E Dump Truck is an off-highway, rear dump truck with AC Electric Drive. The gross vehicle weight is 1,100,000 lbs. (498 960 kg). The engine is a Cum- mins QSK60C rated @ 2700 HP (2014 kW). The Operator’s Cab has been engineered for operator comfort and to allow for efficient and safe operation of the truck. The cab provides for wide visibility, with an integral 4-post ROPS/FOPS stucture, and an advanced analog operator envirnment.
It includes a tinted safety- glass windshield and power-operated side windows, a deluxe interior with a fully adjustable seat with lumbar support, a fully adjustable/tilt steering wheel, controls mounted within easy reach of the operator, and an analog instrument panel which provides the operator with all instruments and gauges which are necessary to control and/or monitor the truck’s operating sys- tems. Alternator (GE-GTA34) The diesel engine drives an in-line alternator at engine speed. The alternator produces AC current which is rectified to DC within the main control cabinet.
The rectified DC power is converted back to AC by groups of devices called “inverters”, also within the main con- trol cabinet. Each inverter consists of six “phase mod- ules” under the control of a “gate drive unit” (GDU). The GDU controls the operation of each phase module. Each phase module contains an air-cooled solid-state switch referred to as a “gate turn-off thyristor” (GTO). The GTO cycles on and off at varying frequencies to create an AC power signal from the DC supply. Power Steering The truck is equipped with a full time power steering system which provides positive steering control with minimum operator effort.
The system includes nitro- gen-charged accumulators which automatically pro- vide emergency power if the steering hydraulic pressure is reduced below an established minimum. The AC power signal produced by each inverter is a variable-voltage, variable-frequency signal (VVVF). Frequency and voltage are changed to suit the operat- ing conditions. AC Induction Traction Motorized Wheels Dynamic Retarding The alternator output supplies electrical energy to the two wheel motors attached to the rear axle housing. The motorized wheels use three-phase AC induction motors with full-wave AC power.
The dynamic retarding is used to slow the truck during normal operation or control speed coming down a grade. The dynamic retarding ability of the electric system is controlled by the operator through the acti- vation of the retarder pedal (or by operating a lever on the steering wheel) in the operators cab and by setting the RSC (Retarder Speed Control). Dynamic Retarding is automatically activated, if the truck speed goes to a preset overspeed setting. The two wheel motors convert electrical energy back to mechanical energy through built-in gear trains within the wheel motor assembly.
The direction of the wheel motors is controlled by a forward or reverse hand selector switch located on a console to the right side of the operator. Blower Brake System Both the inverters and the wheel motors produce heat while in operation and must be cooled. Cooling air is provided by a separate AC drive blower using rectified DC as its power source. Cooling air flow volume is modulated based on thermal requirements. Service brakes at each wheel are oil-cooled multiple disc brakes applied by an all-hydraulic actuation sys- tem. Depressing the brake pedal actuates both front and rear brakes, after first appling the retarder.
All wheel brakes will be applied automatically, if system pressure decreases below a preset minimum. Suspension HYDRAIR ® II suspension cylinders located at each wheel provide a smooth and comfortable ride for the operator and dampens shock loads to the chassis during loading and operation. The parking brake is a dry disc type, mounted inboard on each rear wheel motor, and is spring-applied and hydraulically-released with wheel speed application protection (will not apply with truck moving).