Solved Example of 3 Phase Induction Motor
Let us assume that, A Three-phase induction motor with a synchronous speed of 1500 revolutions per minute (RPM) and a slip of 5%. The motor is connected to a 50Hz three-phase supply. Find the synchronous speed, actual rotational speed and Frequency of the Induced EMF.
Solution
Synchronous Speed
The synchronous speed (Ns) can be calculated using the formula
Ns = 120 x frequency / Number of Poles ,
For a 50 Hz supply and a motor with 4 poles:
Ns = 120 x 50 / 4 = 1500 RPM
Actual Rotational Speed
N = Ns x ( 1 – slip)
Given slip is 5% ( 0.05):
N = 1500 x ( 1 – 0.05) = 1425 RPM
Frequency of the Induced EMF
The slip frequency (fslip) is given by :
fslip = Frequency x Slip
For a 50 Hz supply and a slip of 5% :
fslip = 50 x 0.05 = 2.5 Hz
Hence, The induced EMF frequency in the rotor is 2.5 Hz.
3 Phase Induction Motor
The motor serves the purpose of converting electrical energy into mechanical form. Motors are categorized into AC motors and DC motors based on the type of power supply. In this post, we will talk about the different types of three-phase induction motors with working and applications.
The induction motors especially three-phase induction motors are by and large used AC motors to convey mechanical power in modern applications. 80% of the motor is a three-phase induction motor among all motors used in undertakings. Consequently, the induction motor is the fundamental motor among any excess types of motor.
Table of Content
- Three-Phase Induction Motor
- Three – Phase Power
- Construction
- Squirrel Cage Induction Motor
- Slip-Ring or Wound Rotor Induction Motor
- Working Principle
- Advantages
- Disadvantages
- Applications