Analysis of a Resonant Converter Controlled by Triac
Analytical and experimental considerations in the constant voltage transformer are presented. The constant voltage transformer consists of a linear reactor, a linear transformer, a capacitor, a triac, and a feedback circuit. The feedback circuit is used to make the triac fire precisely at any angle from zero to ¿/2 so as to keep output voltage constant. An analysis of this circuit is presented in which the higher harmonic currents generated in the triac are neglected and the output voltage is assumed to be kept constant. The experimental results agree well with the theoretical value with respect to the load characteristic, the voltage characteristic, the power factor, and the jumping phenomenon.
A new feedback-controlled ferroresonant regulator employing a unique magnetic component
A new feedback-controlled ferroresonant voltage regulator employing a single magnetic structure is presented. By introducing an additional magnetic path through the use of a second set of shunts, all the magnetic functions are provided in a minimum volume. In this new circuit, instead of permitting saturation of the output section of the core, an external control circuit simulates core saturation and provides a means of obtaining precision regulation. This circuit retains all the advantages of ferroresonant regulators such as high reliability and simplicity; in addition it reduces the stray magnetic field and proves to be economical.
Reduction of gas flow nonuniformity in gas turbine engines by means of gas-dynamic methods
Gas flow nonuniformity is one of the main sources of rotor blade vibrations in the gas turbine engines. Usually, the flow circumferential nonuniformity occurs near the annular frames, located in the flow channel of the engine. This leads to the increased dynamic stresses in blades and as a consequence to the blade damage. The goal of the research was to find an acceptable method of reducing the level of gas flow nonuniformity as the source of dynamic stresses in the rotor blades. Two different methods were investigated during this research. Thus, this study gives the ideas about methods of improving the flow structure in gas turbine engine. On the basis of existing conditions (under development or existing engine) it allows the selection of the most suitable method for reducing gas flow nonuniformity.