Pumped Storage Plant These are a special type of power plant which works as ordinary hydropower plants for part of the time and when such plants are not producing power, they can be used as pumping stations which pump water from tail race to the head race. During this time, these plants utilize power available … Read more
Band Gap Theory The Band Gap theory explains the mechanism of conductor, insulators and semiconductor regarding the movement of free electrons from valence band to the conduction band. An energy band which separates the conduction band and the valence band is called Band gap or Forbidden band or Forbidden gap. Based on energy gap, the material … Read more
The comparison of steam power plant with hydroelectric power plant is given in the following table. Points Steam Power plant Hydroelectric Power plant 1. Initial cost per kW in ₹ Initial cost is lower than those of hydroelectric & nuclear power plant (1000 to 1500). Initial cost is very high because of dam construction & excavation … Read more
EHV AC stands for Extra High Voltage Alternating current and HVDC stands for High Voltage Direct current. As compared to EHV AC, HVDC has following advantages and disadvantages. Advantages 1. HVDC systems are economical for long distance bulk power transmission by overhead line (reduced tower costs). 2. There is greater power per conductor and simpler line … Read more
Q. Why the thermal efficiency of a steam power plant is quite low? Ans. In a steam power station, more than 50% of the total heat of combustion is lost as heat rejected to the condenser and this loss is unavoidable as heat energy cannot be converted into mechanical energy without a drop in temperature, … Read more
Since synchronous motors are not self-starting inherently, we should have some means of starting synchronous motors. The methods are given below: 1. Induction Motor Start Damper windings, consisting of copper bronze bars embedded in slots in the pole faces and short-circuited at both ends are usually provided in synchronous motors which serve not only to … Read more
In this article, we will see the difference between Single Cage & Double Cage Induction Motors. Single Cage Double Cage 1. Starting performance As compare to double cage rotor, the single cage has less starting torque so at starting less heating loss occur. A double cage motor develops higher starting torque for low starting current and … Read more
Resistance is classified into three categories as low, medium and high resistance. Medium Resistance ranges from 1Ω to 0.1 MΩ. The different methods used for the measurement of Medium resistance are as follows: Voltmeter-Ammeter method Substitution Method Wheatstone Bridge Method Ohmmeter Method Substitution Method In this section, we will learn about Measurement of Medium Resistance by Substitution Method. In … Read more
Resistance is classified into three categories for the sake of Measurement. Different categories of Resistance are measured by the different techniques. They are classified as Low Resistance: Resistance having value 1Ω or below are kept under this category. Medium Resistance: This category includes Resistance from 1Ω to 0.1 MΩ. High Resistance: Resistance of the order of … Read more
PMMC stands for Permanent Magnet Moving Coil. PMMC Instruments are the most accurate type for the measurement of DC current or voltage. Construction of PMMC Instruments Permanent Magnet Moving Coil or PMMC Instruments consists of following components: Moving Coil Magnet System Control Spring Damping Pointer and Scale 1. Moving Coil The moving coil made up … Read more