Three-Phase Power and Transformers Lab Exercise, Lab Reports of Electrical and Electronics Engineering

Download Three-Phase Power and Transformers Lab Exercise and more Lab Reports Electrical and Electronics Engineering in PDF only on Docsity! - 1 - 08/25/04 Southern Polytechnic State University ECET 3500 Laboratory Exercise No. 3 Electrical and Computer Eng. Tech. Three Phase Power & Transformers Name ____________________________ Date ________ Lab Section ________ Introduction In this exercise you will investigate the basic characteristics three-phase power measurements and three- phase transformer connections. Cautions ! Do not energize a circuit until your instructor checks it. ! Turn-off all power before making changes in a circuit. Procedure 1. Devise a technique to determine the phase sequence of a 208V, 60Hz, three-phase voltage source. Draw a circuit and provide a mathematical derivation to its operation. 2. Determine the phase sequence of both the fixed and the variable three-phase supplies in the EMS 8821 power supply. Phase Sequence of Fixed Supply ________ Phase Sequence of Variable Supply ________ 3. A 120Vline, 60Hz, positive sequence, three-phase supply is to be connected directly to a 120Vline, delta load, each phase of which consists of a 300Ω resistor in parallel with a 400Ω inductive reactance. Measure all phase and line voltages and currents in the system, as well as the three-phase power using the EMS 8431 three-phase wattmeter. 4. A 208Vline, 60Hz, positive sequence, three-phase supply is to be connected to the 120Vline, delta load (described in step three) by means of a three-phase transformer. Determine the transformer connections possible for this configuration, choose one, and connect the circuit. 5. Measure all phase and line voltages and currents in the new circuit, as well as the total three-phase power supplied by the source. 6. Switch off all the resistive and inductive loads, and again measure all voltages, currents, and three- phase power in the network.