Write short notes on construction and working of CO4 a) 3 Phase Induction Motor b) Stepper Motors

a) 3 Phase Induction Motor:

• Construction: A 3 phase induction motor consists of a stator and a rotor. The stator is the stationary part of the motor and is made up of laminated iron cores with evenly spaced windings. These windings are connected to a 3 phase power supply. The rotor, on the other hand, is the rotating part of the motor and is made up of laminated iron cores with conductors embedded in them.
• Working: When the 3 phase power supply is connected to the stator windings, a rotating magnetic field is produced. This rotating magnetic field induces currents in the rotor conductors, which in turn creates a magnetic field in the rotor. The interaction between the rotating magnetic field of the stator and the magnetic field of the rotor causes the rotor to rotate. The speed of rotation is determined by the frequency of the power supply and the number of poles in the motor.

b) Stepper Motors:

• Construction: A stepper motor consists of a rotor and a stator. The rotor is made up of a permanent magnet or a toothed iron core, while the stator is made up of multiple coils or windings. The coils are arranged in such a way that they create a magnetic field when energized.
• Working: Stepper motors work by sequentially energizing the coils in a specific sequence. This sequence of energizing the coils determines the rotation of the motor. When a coil is energized, it creates a magnetic field that attracts the rotor's permanent magnet or toothed iron core. By sequentially energizing the coils in the correct sequence, the rotor moves in small steps, hence the name "stepper" motor. The speed and direction of rotation can be controlled by controlling the sequence and timing of the coil energization.