SINGLE. PHASE OPERATION OF THREE PHASE INDUCTION MOTOR

Abstract

Three phase induction motor is supplied from a single phase public utilities using a new unique reconnection of the machine windings and three capacitors to provide balanced currents and voltage in all of the windings currents for its efficient operation in single phase system. By change of the capacitor value in response to load change so that the single-phase efficiency is close to the three-phase efficiency for all shaft loads between 20 to 120 percent of full load. The single-phase power line power factor was near unity for a wide range. of power factor. This method is applicable to both high efficiency and standard three phase motors without motor modification, where a three-phase supply is not available, this method is applicable. This connection is called smith connection. The smith connection is essentially a asymmetric connection but the suitable choice of the capacitance, balanced current can be injected in to the motors and generator windings for a given speed and load. Inspection equation are established and solved using the method of symmetrical components to simulate the motor and generator performance analysis. Using a Phasor diagram approach the values of capacitances required can be computed. Harmonics analysis of current and voltage waveform in this case is also analyzed using Fourier series. In remote and rural region where only single-phase power supply is available i standard three phases can be in place of single-phase motors. Low cost, short delivery time superior electrical performance, and larger power rating are the main reasons favoring the use of three phase machines in favor of single-phase machine. Experimental work has done to ver ithe theoretical result on a 2.2 kW induction machine. It confirm the validity of the theoretically analysis and of control method