Electrical4U 
High Voltage Test (Water Immersion Test) :A 3-meter-long core sample is taken from the finished cable or cord. The sample is immersed in a water bath at room temperature, with the ends protruding at least 200 mm above the water. After 24 hours, an alternating voltage is applied between the conductor and the water. The … Read more
The relays used in power system protection are of different types. Among them differential relay is very commonly used relay for protecting transformers and generators from localised faults.Differential relays are very sensitive to the faults occurred within the zone of protection but they are least sensitive to the faults that occur outside the protected zone. … Read more
Electrolyte of Lead Acid Battery The electrolyte of a lead acid battery cell is a solution of sulfuric acid and distilled water. The specific gravity of pure sulfuric acid is about 1.84 and this pure acid is diluted by distilled water until the specific gravity of the solution becomes 1.2 to 1.23. However, in some … Read more
A generator is subjected to electrical stresses imposed on the insulation of the machine, mechanical forces acting on the various parts of the machine, and temperature rise. These are the main factors which make protection necessary for the generator or alternator. Even when properly used, a machine in its perfect running condition does not only … Read more
Inter turn stator winding fault can easily be detected by stator differential protection or stator earth fault protection. Hence, it is not very essential to provide special protection scheme for inter turn faults occurred in stator winding. This type of faults is generated if the insulation between conductors (with different potential) in the same slot … Read more
The rotor of an alternator is wound with field winding. A single earth fault in the field winding or exciter circuit is not a major issue. However, if multiple earth faults occur, they can cause short circuits between faulty points on the winding, leading to unbalanced magnetic field and potential mechanical damage to the machine’s … Read more
This is to be noted that, the star point or neutral point of stator winding of an alternator is grounded through an impedance to limit the ground fault current. Reduced ground fault current causes less damage to the stator core and winding during ground or earth fault. If the ground impedance is made quite high, … Read more
Loss of field or excitation in a generator happens when the excitation system fails. In larger generators, excitation energy often comes from a separate auxiliary source or a separately driven DC generator. If the auxiliary supply or driving motor fails, it can cause loss of excitation, making the generator run above synchronous speed.In that situation … Read more
In electrical and electronic systems, an Annunciator is a device that announces faults or unusual activities in the system or process. What is Alarm Annunciator? An alarm annunciator is an audio-visual warning system that highlights faults or potential mishaps. It is crucial for safety as it can warn operators before accidents occur. Let’s explore how … Read more
Electric power can be transmitted or distributed either by overhead transmission systems or by underground cables. Cables are mainly designed for a specific requirement. Power cables are mainly used for power transmission and distribution purposes. It is an assembly of one or more individually insulated electrical conductors, usually held together with an overall sheath. The … Read more