A steady direct current flowing through the conductors is uniformly distributed over the whole cross-section of the conductor. However, an alternating current flowing through the conductor does not distribute uniformly, rather it tends to concentrate near the surface of the conductor as shown in the figure. This is known as skin effect in transmission line. […]
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The ordinary squirrel cage induction motor has excellent running characteristics, but it suffers from the drawback that due to its very low rotor resistance, it’s starting torque is poor. The starting torque can be improved by increasing the rotor resistance but in case of squirrel cage induction motor external resistance can’t be added in the rotor
Speed Control of 3 Phase Induction Motor A 3-phase induction motor is practically a constant-speed machine. The speed regulation of an induction motor (having low resistance) is usually less than 5% at full-load. In these motors, speed reduction is accompanied by a corresponding loss of efficiency and much speed regulation. Different methods by which speed
The various starting methods of induction motor which are employed to restrict the initial rush of current in squirrel cage induction motors are given below: Starting Method of Induction Motor Direct on Line Starting Method of Induction Motor In this starting method of induction motor, the motor is switched on direct to the supply mains
Losses in Induction Motor The losses in induction motor are broadly categorized into two classes, namely constant losses and variable losses. Constant losses in Induction Motor These losses do not depend on the load hence they are known as constant losses. These can be further categorized as under: The no-load test is performed on induction
To draw the torque slip characteristics of induction motor (three phase) following points are considered: T = ksE22R2 / R22 In the above expression, all quantities are constant except slip s. Therefore, T α s Torque Slip Characteristics of Induction Motor Thus, at low values of slip, torque is approximately proportional to slip s and the torque
Full load torque equation of induction motor is as follows: Starting Torque Equation of Induction Motor The starting torque of a motor is that torque which is produce by it at start. It is denoted by Tst and corresponds to s = 1. So by substituting s = 1 in above expression, we get the
Hi friends, in this article I am describing the importance of slip in induction motor and hoping you will find it informative and useful. In the induction motor rotor always rotates speed less than synchronous speed. The difference between the rotor speed (N) and the rotating magnetic flux speed (Ns) is called slip. The induction motor
The induction motor rotates due to the rotating magnetic field in induction motor, which is produced by the stator winding in the air gap between the stator and the rotor. The stator has a three phase stationary winding which can be either star connected or delta connected. Whenever the AC supply is connected to the
The AC induction motor is the dominant motor technology in use today, representing more than 90 percent of installed motor capacity. Induction motors are available in single-phase (1ϕ) and three-phase (3ϕ) configurations, in sizes ranging from fractions of a horsepower to tens of thousands of horsepower. They may run at fixed speeds – most commonly