الفهرس | Only 14 pages are availabe for public view |
Abstract Light is one form of energy. Illumination loads are classified as one of the essential consumers of electrical energy. Therefore, it is important to apply some means of control of light intensity in practical applications such as lighting of studiGs, air ports, emergency lamps, flashing lamps and other uses of illumination loads. The present research starts with an explanation of the basis of light regarding its nature and some basic relations in lighting engineering, and a display of some terms. The introduction of the thesis work contains a classification of the different types of lighting sources and efficiency of each one. There is also an explanation of two different types of artificial light sources namely incandenscent lamps and discharge lamps. At the end of the first chapter there is an explanation of the traditional ways of controlling illumination. In the second chapter there is a detailed explanation of single phase converter circuit. An analysis of the converter circuit is carried out considering the lamp as a pure resistance and considering the semiconductor elements as ideal switches. Both average and effective values of load ii voltage are computed. This chapter also includes harmonic analysis of the voltage and calculations of higher harmo- nics. It also includes a method for the calculation of the power factor of the circuit. At the end of this part a mathematical relation between absorbed power and output light from the lamp is obtained. The third chapter includes an explanation of the experimental circuits in control of lighting uning thyristors. The study starts with a circuit to control light loads with few hundred watts then a display of simple full wave for more developed control circuits is made. A sim- ple type of thyristor circuits which is called triac has been also used as controllers. This chapter includes a description of building up and testine the experimental circuits for control of lighting using triacs. The following relations have been experimentally determined 1. Variation of load voltage with firing angle. 2. Variation of load current with firing angle. J. The effect of variation of firing angle on illumina- tion. 4. Variation of output power with firing angle. 5. Relation between input power and the luminance of the lamp. 6. Comparison between converter circuit and conv~ntional methods in control of light. By the end of this chapter an overview of modern technique using integrated circuits in triggering the triac is given. iii The fourth chapter includes a description of different ways of controlling discharge lamps starting vvith behaviour of this kind of lamps and conditions of the lamps at starting and run up. In this chapter the importance of using starter and a choke coil in conjunction with these kinds of lamps is discussed. The study includes a description of some kinds of electric chokes using res is- tors,coils, capacitors, coils with capacitors as well as electronic chokes. This chapter also contains a brief explanation of some kinds of electric discharge lamps such as fl~Orscent lamps, their circuits, methods of starting and lighting control. It also provides a display of high frequency flUQrescent lamps, high pressure sodium lamps, low pressure sodium lamps and mercury lamps. |