Electrical4U 
A power transformer is the most costly and crucial piece of equipment in an electrical substation. Therefore, it’s important to carry out various preventative maintenance activities to keep it performing well and extend its functional life. A power transformer requires various routine maintenance tasks including measurement and testing of different parameters of the transformer. There … Read more
Temperature Indicator of Transformer These are generally precision instruments. A temperature indicator of power transformer is specially designed for protection of transformer in addition to its temperature indication and cooling control features. That means, this device performs three functions. These instruments indicate instantaneous temperature of oil and windings of transformer. Types of Temperature Indicator of … Read more
A Magnetic Oil level Guage (MOG) is a device used to indicate the position of transformer insulating oil level in conservator of a transformer. This is a mechanical device. A mog in a transformer consists of three main parts: Construction of Magnetic Oil Gauge or MOG The construction of a magnetic oil gauge (MOG) starts … Read more
Function of Radiator When a transformer is loaded, the current starts flowing through it’s windings. Due to this flowing of electric current, heat is produced in the windings, this heat ultimately rises the temperature of transformer oil. We know that the rating of any electrical equipment depends upon its allowable temperature rise limit. Hence, if … Read more
In a three phase system, the phases are conventionally labeled as RYB. A phase sequence indicator is a device that determines the order of these phases in a three-phase supply.When we apply a conventional RYB three-phase supply to an induction motor, the rotor rotates clockwise.Now what will happen to direction of rotation of rotor if … Read more
Before introducing various types of power factor meters, it is essential to understand their importance. We cannot directly calculate power factor in an AC circuit by dividing power by the product of current and voltage from a wattmeter, ammeter and voltmeter because this method is inaccurate and prone to errors. Therefore, industrial applications require accurate … Read more
The Weston type frequency meter works on the principle that when current flows through two perpendicular coils, magnetic fields are produced, causing a magnetic needle to deflect towards the stronger magnetic field, indicating the frequency. Its construction is similar to the ferrodynamic type of frequency meter. The circuit diagram requires two coils, three inductors, and … Read more
Various methods are used for measurement of three phase power in three phase circuits on the basis of number of wattmeters used. We have three methods to discuss: Let us discuss one by one each method in detail. Measurement of Three Phase Power by Three Wattmeters Method The circuit diagram is shown below-This method is … Read more
Instruments that measure reactive power in a circuit are called varmeters. Reactive power in a circuit is calculated using the formula VIsinA.Here there is no need to give an explanation about the physical meaning of reactive power, as only a mathematical relation is sufficient. Measurement of reactive power is essential because if the reactive power … Read more
In the early days, only conventional over-current relays were used for busbar protection. The goal was to ensure that faults in any feeder or transformer connected to the busbar did not affect the entire busbar system. However, the time settings of these relays were lengthy, causing delays in isolating faults on the busbar itself, which … Read more