ENGINEERING ARTICLES

Star-delta starters are a popular method for starting electric motors. They provide a number of benefits and can be used in a variety of applications. In this article, we will explore the advantages of using a star-delta starter for motor control, as well as some of the applications in which they are commonly used. One of the main benefits of a star-delta starter is that it reduces the inrush current when starting a motor. Inrush current is the surge of current that flows through a motor when it is first turned on. This surge can cause damage to the motor and to other electrical equipment on the same circuit. By using a star-delta starter, the inrush current is reduced, which protects the motor and other equipment. Another benefit of a star-delta starter is that it reduces the torque during the starting phase. This is important because motors can generate very high torque during the starting phase, which can cause damage to the driven equipment. By reducing the torque during the starti...

Electrical engineering is a field that has revolutionized the world we live in, from powering our homes to enabling us to communicate with anyone in the world at any time. With the increasing demand for sustainable energy and the rapid pace of technological advancements, the field of electrical engineering is ripe with opportunities for growth and development. In this article, we will discuss some of the current trends and challenges in electrical engineering and the impact they have on the modern world. One of the key areas of focus in electrical engineering is renewable energy. With climate change becoming a pressing issue, the need for sustainable energy sources has never been greater. Electrical engineers are at the forefront of developing new technologies to harness renewable energy sources such as solar, wind, and hydro power. This has resulted in a growing demand for skilled electrical engineers who can design, install, and maintain these renewable energy systems. Another area o...

Sr# Bi-Polar Junction Transistor (BJT) Metal Oxide Field Effect Transistor (MOSFET) 1 It is a Bipolar Device It is majority carrier Device 2 Current control Device Voltage control Device. 3 Output is controlled by controlling base current Output is controlled by controlling gate voltage 4 Negative temperature coefficient Positive temperature coefficient 5 So, paralleling of BJT is difficult. So, paralleling of this device is easy. 6 Dive circuit is complex. It should provide Dive circuit is simple. It should provide 7 constant current (Base current) constant voltage (gate voltage) 8 Losses are low. Losses are higher than BJTs. 9 So used in high power applications. ...

When carrying out the work of cable laying in the underground transmission line, the trench is to be dug/ prepared. Trench work should be done by following safety precautions. All pits and trench work shall comply with WorkSafe requirements, particularly the WorkSafe Code of Practice: Excavation. They may include but are not limited to: When a pit is to be left open overnight, proper barrier mesh and flashing lights, etc as required or the pit must be covered. Soil must be piled safely back from the edge of the pit. Pits or trenches deeper than 1500mm in normal soil may require a ladder for access and require shoring, benching or sloping of the sides of them. Pits or trenches may require shoring if less than 1500mm deep and the soil is unstable. Undermining walls, foundations, streets or pavements are to be avoided otherwise appropriate shoring is required. All shoring, benching and sloping must be installed. Barriers shall be erected to vehicles inadvertently falling into the excavati...

The transmission lines are used to transmit the power for long-distance. There are two types of transmission lines; Overhead Transmission line Underground Transmission line Overhead transmission line uses bare conductors. These conductors placed at a height from the ground. To maintain clearance between the conductors and ground, supporting towers are used. The voltage of the transmission line decides the height of the tower. The insulators used to provide insulation between the conductor and the tower. As the transmission voltage level increases, the height of the tower increases to provide more clearance between the ground and conductors. In the underground transmission system, the number of conductors bunched together with proper insulation. The underground cable provided with lead sheet and armoring. These provide protection against moisture and mechanical injury. As the voltage level increase, the thickness of insulation increases.   Overhead Line ...

I) PRIMARY SENSING ELEMENT This is the element that first receives energy from the measured medium and procedures an output depending on some way on the measured quantity (measured).  The output is some physical variable e.g. displacement or voltage. An instrument always extract some energy from the measured medium. The measured quantity is always disturbed by the act of measurement, which makes a perfect theoretically impossible. Good instruments are designed to minimize this loading effect.  II) VARIABLE CONVERSION ELEMENT If may be necessary to convert the output signal of the primary sensing element to another more suitable variable while preserving the information content of the original signal. This element performs this function.  III) VARIABLE MANIPULATION ELEMENT An instrument may require that a signal represented by some physical variable be manipulated by some way.  By manipulation we mean specifically a change in numerical ...

Resistive Load Resistive loads can be purely resistive or of the tungsten-heater load type. A resistive load that has no heating element is the easiest for a switch to handle, and the switch’s rating is based on this type of load. A resistive load is one in which 100% of the load is composed of resistive devices. The power factor is high (PF = 1) and contact erosion is low. Consequently, the switch’s electrical life can be anticipated with some certainty.  Lamp Load When a switch closes on a resistive lamp load, the switch sees a short circuit because the cold resistance of the lamp filament is near zero. The surge current as the switch closes can be many times the steady state current. As the lamp filament heats up to operating temperature, the resistance of the filament increases and the current decreases to the lamp’s steady state.  Motor Motor loads present yet another brutal environment for switch contacts. Closing the switch contact on a motor st...