Electrical Engineer

  What is Corona Effect in Transmission Line? When the two conductors of a transmission line are connected to an alternating potential difference, whose spacing is large in comparison with their diameter, then the atmosphere air surrounding the two conductors is subjected to electrostatic stresses. When this potential difference is low, there is no change in the condition of atmosphere air around the conductors. When the potential is gradually increased and reaches a value called Critical Disruptive Voltage, the air between the conductor starts ionization (starts producing ions) and a faint luminous glow of violet color appears because of the electrostatic stresses on the surrounding air. This phenomenon is called Visual Corona and is accomplished by the production of ozone gas, radio interference, and hissing noise . If the potential difference is further increased, the glow and noise will increase rapidly and result in the breakdown of the air insulation that leads to spark over. The

  AC and DC current are the two types of electrical current that are used in different applications. The main difference between the two is the direction of the flow of electrons. In AC current, the direction of the flow of electrons changes periodically, while in DC current, the direction of the flow of electrons is constant. AC current is generated by devices such as generators and alternators. It is used in most homes and buildings for powering lights, appliances, and other electronic devices. It is also used in power transmission systems to transmit electricity over long distances. The main advantage of AC current is that it can be easily transformed into different voltages using a transformer, which makes it more efficient for power transmission. DC current, on the other hand, is generated by devices such as batteries and solar cells. It is used in applications such as electric vehicles, electronic devices, and certain industrial processes. The main advantage of DC current is that

  Torque Slip Characteristics of 3-Phase Induction Motor The graph plotted between the torque and slip for a particular value of rotor resistance and reactance is known as   torque-slip characteristics   of the induction motor. The torque of a 3-phase induction motor under running conditions is given by, τ r = K s E 2 2 R 2 R 2 2 + ( s X 2 ) 2 … ( 1 ) From the eqn. (1), it can be seen that if R 2  and X 2  are kept constant, the torque depends upon the slip 's'. The torque-slip characteristics curve can be divided into three regions, viz. Low-slip region Medium-slip region High-slip region Low-Slip Region At synchronous speed, the slip s = 0, thus, the torque is 0. When the speed is very near to the synchronous speed, the slip is very low and the term (𝑠𝑋 2 ) 2  is negligible in comparison with R 2 . Therefore, τ r ∝ s R 2 If R 2  is constant, then τ r ∝ s … ( 2 ) Eqn. (2) shows that the torque is proportional to the slip. Hence, when the slip is small,  the torque-slip curve