Ungrounded Neutral System: In an ungrounded neutral system, the neutral is not connected to the ground i.e. the neutral is isolated from the ground. Therefore, this system is also called isolated neutral system or free…
Underground Cables Interview Questions and Answers: 1. For what purpose metallic sheath is provided in underground cables ? Ans. The metallic sheath is provided around the insulation to protect it against ingress of moisture, gas…
Underground Cables: Electric power can be transmitted or distributed either by overhead system or by underground cables. The underground cables have several advantages such as less liable to damage through storms or lightning, low maintenance cost,…
Uncompensated Large Time Constants: It is possible to compensate only one Uncompensated Large Time Constants using a PI controller. A PID controller is used to compensate for two large time constants. On technical grounds, compensation…
Unbalanced Three Phase Circuit Analysis: Types of Unbalanced Loads - An unbalance exists in a circuit when the impedances in one or more phases differ from the impedances of the other phases. In such a…
Unbalanced Source Voltages Operations: As Supply voltage may sometimes become unbalanced, it is useful to know the effect of Unbalanced Source Voltages Operations on motor performance. Further, motor terminal voltage may be unbalanced intentionally for…
Unbalanced Rotor Impedance Operation: Earlier Unbalanced Rotor Impedance Operation were employed for starting and speed control. They are not in use any more. However, a loose contact in the rotor circuit can cause unbalance in…
Unbalanced Phase Current: The Unbalanced Phase Current in a 3-phase system can be expressed in terms of symmetrical components as under : Fig. 18.6 shows the vector representation of symmetrical components. It is usually profitable…
Unbalanced Loading Protection of Generator: Unbalanced Loading Protection of Generator - Whatever be the cause of the unbalance it is obvious that the negative phase sequence current will result in heating of the stator. In…
Ultrasonic Welding Working Principle and Applications: Ultrasonic welding is a solid state welding process that produces coalescence of materials by the local application of high-frequency (20-60 kHz) vibratory energy as the workpieces are held together…
