Electric Motor
The Cage Induction Motor Explained In Details
This simplest form of AC induction motor or asynchronous motor is the basic, universal workhorse of industry. Its general construction is shown in Fig. 1. It is usually designed for fixed-speed operation, larger ratings having such features as deep rotor… Read more
Dec 29, 2011 | By Edvard Csanyi
Energy and Power
Using Core-Balance Current Transformer For Earth Fault Protection
The core-balance current transformer (or CBCT) is normally of the ring type, through the centre of which is passed cable that forms the primary winding. An earth fault relay, connected to the secondary winding, is energised only when there is… Read more
Dec 28, 2011 | By Edvard Csanyi
Industrial Automation
Ladder diagrams and the PLC for electrical engineers – beginners
The ladder diagram has and continues to be the traditional way of representing electrical sequences of operations. These diagrams represent the interconnection of field devices in such a way that the activation, or turning ON, of one device will turn… Read more
Dec 27, 2011 | By Edvard Csanyi
Protection
Transformer Protection – Abstract from NEC
According to NEC 450.4, “each transformer 600 volts, nominal, or less shall be protected by an individual overcurrent device installed in series with each ungrounded input conductor.” Such overcurrent device shall be rated or set at not more than 125%… Read more
Dec 26, 2011 | By Jignesh Parmar
Energy and Power
What psychological effect does an electric shock?
Most of us have experienced some form of electric ”shock”, where electricity causes our body to experience pain or trauma. If we are fortunate, the extent of that experience is limited to tingles or jolts of pain from static electricity… Read more
Dec 25, 2011 | By Edvard Csanyi
Industrial Automation
PROFIBUS at a Glance
PROFIBUS is an open, digital communication system with a wide range of applications, particularly in the fields of factory and process automation. PROFIBUS is suitable for both fast, time-critical applications and complex communication tasks. PROFIBUS communication is anchored in the… Read more
Dec 24, 2011 | By Edvard Csanyi
Electric Motor
Motor starting problem and high motor inrush currents
Electric motor protection device depends on the accurate and correct selection of overload(s), fuses and/or circuit breakers. Over the years the protective devices have been selected according to the applicable code requirements with only minimal nuisance tripping. However, in recent… Read more
Dec 23, 2011 | By Edvard Csanyi
Medium Voltage
Consequences of internal arc for personal safety and MV electrical equipment
The aim of this article is to describe the internal arc phenomenon, its consequences for safety, current methods of limiting them and current regulations in general for equipment used in medium-voltage electrical distribution networks. Internal arcs can occur in electrical… Read more
Dec 23, 2011 | By Edvard Csanyi
Energy and Power
What is HIPOT Testing (Dielectric Strength Test)?
Hipot Test is short name of high potential (high voltage) Test and it is also known as Dielectric Withstand Test. A hipot test checks for “good isolation”. Hipot test makes surety of no current will flow from one point to… Read more
Dec 22, 2011 | By Jignesh Parmar
Industrial Automation
When we started to use PLCs after all?
PLCs (Programmable Logic Controllers) were first introduced in the 1960’s. The primary reason for designing such a device was eliminating the large cost involved in replacing the complicated relay based machine control systems. Bedford Associates (Bedford, MA) proposed something called… Read more
Dec 21, 2011 | By Edvard Csanyi
Electrical Lectures
Earthing in electrical network – purpose, methods and measurement
The main reason for doing earthing in electrical network is for the safety. When all metallic parts in electrical equipment are grounded then if the insulation inside the equipment fails there are no dangerous voltages present in the equipment case…. Read more
Dec 19, 2011 | By Jignesh Parmar
Electric Motor
Major difference between a 2-phase and a 3-phase stator
For purposes of explaining rotor movement, let’s assume that we can place a bar magnet in the center of the stator diagrams of figure 0. We’ll mount this magnet so that it is free to rotate in this area. Let’s… Read more
Dec 17, 2011 | By Edvard Csanyi
Medium Voltage
Internal arc testing of MV switchgear – IEC 62271-200 (part three)
Continued from: Internal arc testing of MV switchgear – IEC 62271-200 (part two) The following chapter describes the development of a new gas-insulated switchgear generation GHA [4] for primary distribution for internal arc testing according to IEC 62271-200. All tests… Read more
Dec 16, 2011 | By Edvard Csanyi
Medium Voltage
Internal arc testing of MV switchgear – IEC 62271-200 (part two)
Continued from: Internal arc testing of MV switchgear – IEC 62271-200 (part one) The current valid international standard for metal-enclosed switchgear and controlgear for rated voltages from 1 kV and up to and including 52 kV is written in the… Read more
Dec 14, 2011 | By Edvard Csanyi
Electronics
Capacitor Types
In the market, there are several types of capacitors that have been manufactured. Although all capacitors work essentially the same way, key differences in the construction of different capacitor types makes an enormous difference in their properties. Each capacitor type… Read more
Dec 13, 2011 | By elaina
