29-08-2017, 02:14 PM
Due to the robust construction and ease of control, three-phase asynchronous motors are widely preferred over many other motors for AC motor driven applications. This three-phase motor is responsible for larger load operations in various applications such as goods and elevators, conveyors, compressors, pumps, ventilation systems, industrial fan controllers, etc.
With the invention of adjustable speed drives and various other types of motor starters, three-phase motors have become favorable impellers for variable speed applications. Since these engines are important in cargo handling, it is also important to ensure their safety and protection against starting inrush currents, overcharging, single phasing, overheating and other faulty conditions. Before going into the details of these motors and their protection systems, let's look at the fundamentals of the three-phase motor.
The induction motor or asynchronous motor is the motor most used in diverse applications. Because, these motors always operate at a lower speed than synchronous speed. The synchronous speed can be defined as, the speed of the magnetic field that is rotating in the stator. Induction motors are classified into two types based on the type of input supply, such as single-phase induction motor and three-phase induction motors. Induction motors are classified into four types viz; The split-phase induction motor, the induction motor start the capacitor, the capacitor start the capacitor operation of the induction motor and the induction motor shaded pole. And also on the basis of the rotor type three phase induction motors are classified into two types as type of wound,.
Operating principle
In a DC motor, it is necessary to supply the rotor winding as well as the stator winding. But on this motor, only AC power is supplied with the stator winding.
The alternating flux is formed around the stator winding due to the AC supply. This flow rotates with a synchronous speed called RMF (Rotating Magnetic Field). An induced emf can be caused by the comparative speeds between the rotor conductors and the stator RMF. According to Faraday's electromagnetic induction law, the rotor conductors are short-circuited, and later the rotor current is generated due to an induced emf. That's why these engines are called induction motors.
Now, the current that is induced in the rotor will also create an alternative flow around it. According to Lenz's law, the direction of the induced rotor current is, will tend to oppose the cause of its production.
With the invention of adjustable speed drives and various other types of motor starters, three-phase motors have become favorable impellers for variable speed applications. Since these engines are important in cargo handling, it is also important to ensure their safety and protection against starting inrush currents, overcharging, single phasing, overheating and other faulty conditions. Before going into the details of these motors and their protection systems, let's look at the fundamentals of the three-phase motor.
The induction motor or asynchronous motor is the motor most used in diverse applications. Because, these motors always operate at a lower speed than synchronous speed. The synchronous speed can be defined as, the speed of the magnetic field that is rotating in the stator. Induction motors are classified into two types based on the type of input supply, such as single-phase induction motor and three-phase induction motors. Induction motors are classified into four types viz; The split-phase induction motor, the induction motor start the capacitor, the capacitor start the capacitor operation of the induction motor and the induction motor shaded pole. And also on the basis of the rotor type three phase induction motors are classified into two types as type of wound,.
Operating principle
In a DC motor, it is necessary to supply the rotor winding as well as the stator winding. But on this motor, only AC power is supplied with the stator winding.
The alternating flux is formed around the stator winding due to the AC supply. This flow rotates with a synchronous speed called RMF (Rotating Magnetic Field). An induced emf can be caused by the comparative speeds between the rotor conductors and the stator RMF. According to Faraday's electromagnetic induction law, the rotor conductors are short-circuited, and later the rotor current is generated due to an induced emf. That's why these engines are called induction motors.
Now, the current that is induced in the rotor will also create an alternative flow around it. According to Lenz's law, the direction of the induced rotor current is, will tend to oppose the cause of its production.