Electrical4U 
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
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
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
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
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
MHD generation, also known as magneto hydrodynamic power generation, directly converts heat energy to electrical energy without intermediate mechanical conversion. This process achieves substantial fuel economy by eliminating the steps of mechanical energy production and its subsequent conversion to electrical energy. History of MHD Generation The concept of MHD power generation was introduced for the … Read more
On Load Tap Changer or OLTC In largerpower transformers, for proper voltage regulation of transformer, an on load tap changer is required. As there is no permission of switching off the transformer during tap changing. The tapping arrangement, is placed in separate divertor tank attached to electrical power transformer main tank. Inside this tank, the … Read more
The Polarization Index Test (PI Value Test) and Insulation Resistance Test (IR Value Test) are performed on high-voltage electrical machines to check the insulation’s condition. The PI test specifically evaluates the dryness and cleanliness of the insulation.In the insulation resistance test, a high DC voltage is applied to the insulator. The voltage is divided by … Read more
When studying electrical protective relays, we often use specific terms. To understand how different protective relays work, it’s essential to know these terms. Key terms include: Pick Up Current of Relay In all electrical relays, the moving contacts are held in place by a continuous force, known as the controlling force. This force keeps the … Read more
Induction Cup Relay This relay is a version of the induction disc relay. Induction cup relays work on the same principle as induction disc relays. The basic construction of this relay is similar to a four-pole or eight-pole induction motor. The number of poles in the protective relay depends on the number of windings needed. … Read more