K. Dasgupta

Steady-state performance investigation of open-circuit hydrostatic drives used in the rotary head of drill machine

This paper highlights the steady-state performance of open-circuit hydrostatic drives for the rotary head of drill machine through modeling and experiment. In this respect, two alternative drive systems are considered. A drive system that consists of a variable displacement pump and two high-speed low-torque hydro-motors with a gear reducer unit and the other one consists of an identical pump and a low-speed high-torque hydro-motor. The steady-state model of the proposed drive arrangements is made by bondgraph simulation technique, where the relationship of the various losses of the components are obtained as a function of operating parameters and are identified experimentally. Using them, the slip and torque loss along with the overall efficiency of the drives are characterized. The performances of the hydrostatic drives are compared for the usual operating speed range of the drill machine used in mining operation. The studies made also identify the operating range of the proposed hydrostatic drives with reasonable efficiency.

Dynamic analysis of a hydro-motor drive system using priority valve

The priority valve is considered to be one of the critical parts of the hydraulic system used in mining equipment. This article analyzes the dynamic performance of a hydro-motor drive system using priority valve through system modeling and simulation. A typical hydraulic system of a mining equipment is considered for the analysis, where a stable source of flow is supplied to two hydro-motors through priority flow divider valve. Bondgraph simulation technique is used for the modeling of the complete system, which is validated experimentally. The influences of some key parameters on the transient response of the system have been studied through simulation. The work presented in this article forms the basis idea for the design and optimization of the priority flow control valve for a given application.

Analysis of decay characteristics of an accumulator in an open-circuit hydrostatic system with pump loading

The effects of the decay characteristics of a hydraulic accumulator on the responses of the hydrostatic drive system used in mining vehicles are studied in this article. The system considered for the analysis basically consists of a hydraulic pump, hydro-motor, accumulator and a loading circuit. The studies have been carried out with respect to two different sizes of accumulators. The system model has been made in MATLAB/Simulink® environment. The simulation test results are obtained with respect to the hydro-motor speeds and the system pressure at different resistive loads and capacities of the accumulator and they are verified with the experimental test data. Using the validated model, the parametric studies are also made on the speed responses of the hydrostatic drive for different precharge pressures of the accumulator and inertial load on the motor shaft. The studies made in this article may be useful for the selection of proper capacity of accumulators incorporated in the hydrostatic drive system in mining vehicles.