Motor contactors – Construction and Working of Contactors

A contactor is an electrical device that is used for switching on or switching off electrical circuits. Contactors are employed for controlling electric motors. In this article, you’ll learn the basic construction and working of contactors. To start up and shut down a three-phase AC induction motor, any three-pole switch with a suitable current rating … Read more

Programmable Logic Controller – PLC Questions with Brief Answers

Programmable Logic Controller Questions with Brief Explanatory answers. What is programmable logic controller A programmable logic controller or PLC is a general-purpose controller that can be programmed or instructed by the end-user. A PLC may be instructed to do almost anything with the signals it receives from the input device. In the beginning, PLCs were … Read more

Variable Frequency Drives – Everything about VFDs by ElectricalEngineering.XYZ

Variable frequency drives are the high-power circuits that are designed to produce varying frequencies by which they provide useful power over a wide range of speeds for an AC motor to run. This article briefly explains the working of VFDs and its practical applications and working. Synchronous speed, frequency, and poles of the induction motor … Read more

Voltage Divider Feedback in Operational Amplifier

If we add a voltage divider to the negative feedback wiring so that only a fraction of the output voltage is fed back to the inverting input instead of the full amount, the output voltage will be a multiple of the input voltage (please bear in mind that the power supply connections to the op-amp have been omitted once … Read more

Efficiency of Steam Power Plant

The overall efficiency of a steam power station is approximately 33 to 48%. There are two major reasons behind this low efficiency. Heat is lost in condenser when converted into mechanical energy Heat losses at various stages of the plant Thermal efficiency of Steam Power Plant It is defined as the ratio of corresponding heat … Read more

SCR MCQ – Silicon Controlled Rectifier Multiple Choice Questions

SCR MCQs Names of Terminals of SCR SCR has three terminals namely the: Anode, Base, Cathode Anode, Cathode, Gate Anode, Cathode, Drain Anode, Base, Drain Correct answer: 2. Anode, cathode, gate SCR Behavior as Uni or Bidirectional An SCR behaves as Unidirectional switch Bidirectional switch Mechanical None of the above Correct answer: 1. Unidirectional switch … Read more

Negative feedback in Operational Amplifier

If we connect the output of an op-amp to its inverting input and apply a voltage signal to the noninverting input, we find that the output voltage of the op-amp closely follows that input voltage (I’ve neglected to draw in the power supply, +V/-V wires, and ground symbol for simplicity): As Vin increases, Vout will increase in … Read more