21-10-2014, 12:28 PM
Abstracts: This Project aim is protection of the three phase Induction motors. The circuit will take the full control of the motor and it will protect the motor from several faults such us overloading and short circuit. The circuit will switch on the motor under safety conditions. This also protects induction motor from single phasing and phase changing problem which is also a major fault. When we start the induction motor it takes over load current which is 6 to 7 times rated full load current. By using soft starter we can reduce this starting over load current and provide smooth start for the induction motor. Single phasing preventer is an intelligent system that continuously monitored all the three phase voltage and any of these three phases is disconnected then this system takes the preventive action. The preventive action could be disconnecting the power supply immediately to the load by operating an electromagnetic relays. When phase changing take place at the running condition of motor the negative sequence current produced in rotor. It could cause dangerous overheating in rotor. By using phase changing detector motor also protect against phase changing.