The most important parts used in the three phase transformer are windings and core. Some other parts such as a tank, conservator, bushing, breather etc. are also used along with the core and windings. Simplified construction of a three phase transformer is shown in the figure. Parts of Three Phase Transformer Laminated Steel Core: The […]
The electrical energy generated at the power stations is conveyed to the consumers through a network of transmission and distribution systems. In the power system, the electrical energy generated at the power stations is conveyed to major sub-stations. From the major sub-stations, it is conveyed to the bulk power consumers by high voltage distribution system
Corona Effect in Transmission Lines It can be noticed that near the overhead lines, there exists a hissing noise and sometimes a faint violet glow. The effect due to which such phenomenon exists surrounding the overhead lines is called the corona effect. When a normal alternating voltage is applied across two conductors with enough spacing
When the load is supplied there are line losses due to the resistance of the line conductors. Therefore, the power received at receiving end is always less than the sending end voltage. Efficiency of Transmission Line The ratio of receiving end power to the sending end power of a transmission line is called the transmission
Voltage Regulation & Efficiency of Transmission Line Read More »
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.
Skin Effect and Proximity Effect in Transmission Line Read More »
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