05-11-2014, 09:53 AM
Abstracts: Induction motors are widely used in industries and have a great extent usage than any other motors nearly 80 percent of the total drives used. The reason is the wide variety of characteristics like robustness, self starting, high efficiency, low cost, reliability, speed control flexibility, etc. These are available at different ratings; based on the load requirement the motor is selected. The squirrel- cage design is the most widely used electric motor in industrial applications.Protections of these motors are necessary against the insulation failure, overload conditions, under voltage, voltage unbalancing, phase failure, etc. due to these faults the motor to draw high currents leads to burn out or stops the motor. The project is designed to protect an induction motor from single phasing and over temperature. Single phasing occurs when the one of the phase is removed or broken. And over temperature is due to overloading. In industries production is not hampered owing to failure of any motor so the protection is mandatory for every motor.The project is designed to protect an induction motor from single phasing and over temperature.The basic idea for the development of this project is to provide safety to the industrial motor/pump/lift Motor etc.If any of the phases, out of the 3 phases is missing or if the temperature of the motor during operation exceeds the threshold value, motor stops immediately.The system uses a 3-Phase power supply where three single phase transformers are connected to it.If any of the phases is not available the corresponding transformer stops supplying power to the circuit.This leads to relay getting Switched OFF.Thus the main relay that delivers 3 phase Supply to the motor gets disconnected.A temperature sensor is connected to the motor Body to sense the temperature.