Daily Archives: 13 March 2015

A New Approach on The Diagnosis of Automatic Block Signaling Installations

13 March 2015Fără categoriecburada

Abstract 

This work presents a new vision on the diagnosis of railroad Automatic Block Signal Installations (ABS), using the current modern technologies that involve mobile devices or personal computers. The ABS installation is the system of signals between two consecutive railroad stations, stations centralized either electrodynamically (with electromagnetic relays) or electronically (using computers). The system of signals ensure the command and control of traffic train. Currently, failure diagnosis of such installations is done by the staff working in the Signals, Centralizations, Block (SCB) department of the railroad company. The diagnosis time depends on the professional qualifications of the staff (detailed knowledge of the installation’s functioning principles, of the electrical diagrams and related installations), on the practical diagnosis and recovery competencies. A long diagnosis time causes train traffic delays which, in turn, cause passenger discomfort and losses for the transporter companies. In this work we present diagnosis charts for two types of failures of the ABS installation: Failures of the 220 V power circuits in the ABS boxes, and failures of the Transmitting Relays (TR or T) power circuits. The diagnosis charts and their software implementation assist the maintenance staff in quick detection the failure causes for these types of ABS installations. This solution leads to shorter train delays, higher rail traffic security, and to the optimization of the transport services.

Embedded System for Controlling the Temperature Inside of an Electric Furnace

13 March 2015Fără categoriecburada

Abstract 

We have been listening for a long time to the wide functionality that industrial automation technologies can offer for improving the processes and adding security to the plants and the parts of them. However the price and an unstable market have restricted the deployment of such systems. Nowadays, companies offer too technology-dependent solutions which do not cover user demands completely. Meanwhile, papers from the literature focus on small innovations on specific parts of the industrial automation systems, which do not consider integration and deployment issues, in order to present practical designs [1]. The system presented in this work considers user requirements, including novel advances, all in an integral automation solution suitable for thermal treatments. The modular nature of the architecture allows direct adaptation to specific cases using standard technologies, and a proposal of an IP-based network for connecting the main automation module with the rest of plant. The main purpose of the entire plant is to monitor and control in real-time the temperature of the parts inserted into a resistive furnace. The software is based on m-files that contain the source code that calculates the control coefficients for the next step for ventilation and heating, it verifies the failures that could occur and creates a matrix of the coefficients, in order to make graphics.

Pulse and Transition Measurements in Dynamic Regimes of Electrical Motors

13 March 2015Fără categoriecburada

Abstract 

The paper deals with a modern solution to measure and analyses selected parameters of any electric motor. A virtual instrument with multiple options for selecting the analyzed parameters is described. The values of motor measurement voltages, currents and speed are read from a specified folder. With the virtual instrument presented in this paper it can be see the motor currents, voltages and speed waveforms and from the acquired data and recorded a set of parameters are computed. Boolean selector determine which signals are selected from the original seven signals (three current, three voltages and speed). It can be extract portions of data from the input signals. The extract portion is defined by begin of the offset (point of start) and the length (end the extraction). This instrument allow timing and transition measurements such as: pulse duration (pulse width), duty cycle (duty factor), preshoot (%), overshoot (%), slew rate. Also this virtual instrument allow to find the first highest (maximum) and the lowest (minimum) point in a set of values in signals of currents, voltages or motor’ speed and find the time of the maximum and minimum values so determined. Knowing these values can be determined the range from the lowest point to the highest point in a set of motor’s start current and voltage.

Influence of the Environmental Aspects on the Quality of the Activity of the Wastewater Treatment Plant from the Repairs Locomotives Industry

13 March 2015Fără categoriecburada

Abstract 

The aim of this paper is to identify an engineering method to study and to optimize the process of treating the wastewaters from the repairs locomotives industry in terms of quality, cost and environmental impact. The main purpose of this paper is to show how the control systems allowed us to investigate the environmental aspects of a wastewater treatment plant. The final issue is to optimize the process in terms of quality which means to decrease the cost and environmental impact. There are few steps to obtain the final issue. The first step is to establish the flux diagram of the wastewater treatment plant activity in the context of repairing locomotives process. The second step is to define this activity as a sum of processes according with ISO 14001 Standard, aimed to identify the interaction between this processes. To do this must be described the control system of a wastewater treatment method based on Dissolved Air Flocculation (DAF), used to treat the waste waters results from the locomotive repairs activity. A case study was made on a pumping station to illustrate the influence of the control system on this activity. All these sentences were made with environmental tools like: ad-hoc methods and control list methods, Environmental Systems Analysis (ESA) tools, critical synthesis of the processes and theirs modeling, observation and the experiment and statistic calculus. The result of this work is a work procedure in the activity of control quality of the repairs activity, being a practical implementation. The theme is completely original and responds to an actual practice of Environmental Management System.

Analyzing of the Air Preheater Operation of the Steam Generators in Power Plants

13 March 2015Fără categoriecburada

Abstract 

The paper presents, in the firs part, the importance of the steam generator in the operation of power plants, especially, the importance of the air preheater, the last heat exchange surface on the route of the flue gas, with all physical phenomena produced, which lead to the shaping of the physical model. Then is presented the model in relative units imposed by the literature. The paper proposes the development of a mathematical model in absolute units and the simulation the operation of the air preheater of the steam generator. The theoretical model proposed is implemented in Matlab-Simulink obtained simulations in dynamic regime. In order to validate de model, the simulation results were compared with the parameters measured values of the installations during the real time function. The model wants eliminating the major recalculation sequence of parameters at each step – the patterns in relative units the entire set of coefficients are determined and entered into the model according to the parameters achieved in the previous reference system and meet operating values taken as the basis in developing the work. The approach of such a study is justifies by the development and use of computer technology and digital media communication in dynamic analysis of energy processes.

HID Lamps Dimming Possibilities in the Africa’s Lighting Systems Context

13 March 2015Fără categoriecburada

Abstract 

HID lamps are wide used in lighting systems, also in indoor and outdoor applications. The ballasts necessary for their normal operation could be magnetic or electronic and in the last decade we assist to a debate on which is a better option, the dimming capabilities being one of the most claimed advantages of the electronic ballasts. But, in the last years, several lower cost solutions for getting dimmability with magnetic ballasts have been reconsidered. In this paper, the possibility to dim lamps trough the classical voltage amplitude modulation by means an autotransformer is explored. This solution can be cheaper, robust and most suited for the low budget Africa’s lighting systems. To understand the context, two lighting systems from Antananarivo, capital of Madagascar, and Dakar, capital of Senegal, have been depicted. Experimental tests have been performed on 250 W HID lamps, a High Pressure Sodium (HPS) and a Metal Halide (MH), operated by Very Low Loss magnetic ballast. The range of the voltage modulation has been from 160 V to 250 V and the power consumption, the light output and the harmonics content have been recorded. The energy saving per lamp by dimming to 160V is about 50 to 55% for the considered lamps.