Energy and Power
How circuit breaker trip unit works?
In addition to providing a means to open and close its contacts manually, a circuit breaker must automatically open its contacts when an overcurrent condition is sensed. The trip unit is the part of the circuit breaker that determines when… Read more
Mar 10, 2011 | By Edvard Csanyi
Energy and Power
Calculating lightning strike distance
Return stroke current magnitude and strike distance (length of the last stepped leader) are interrelated. A number of equations have been proposed for determining the striking distance. The principal ones are as follows: S = 2 x I + 30(1−e… Read more
Mar 09, 2011 | By Edvard Csanyi
Metering
D’Arsonval Meter Movement
The most commonly used sensing mechanism used in DC ammeters, voltmeters, and ohm meters is a current-sensing device called a D’Arsonval meter movement (Figure 1). The D’Arsonval movement is a DC moving coil-type movement in which an electromagnetic core is… Read more
Mar 08, 2011 | By Edvard Csanyi
Wind Power
What happens when the wind doesn’t blow?
One of the questions most often asked about wind power is ‘what happens when the wind doesn’t blow’. In the big picture wind is a vast untapped resource capable of supplying the world’s electricity needs many times over. In practical… Read more
Mar 07, 2011 | By Edvard Csanyi
Energy and Power
Early years of Nikola Tesla
Nikola Tesla was born “at the stroke of midnight” with lightning striking during a summer storm. He was born in Croatia in the Austro-Hungarian Empire. The midwife commented, “He’ll be a child of the storm,” to which his mother replied,… Read more
Mar 05, 2011 | By Edvard Csanyi
High Voltage
Economics of GIS
The equipment cost of GIS is naturally higher than that of AIS due to the grounded metal enclosure, the provision of an LCC, and the high degree of factory assembly. A GIS is less expensive to install than an AIS…. Read more
Mar 04, 2011 | By Edvard Csanyi
HVAC
District heating – Heat from a central boiler plant
District heating is a system which provides a number of buildings with heat from a central boiler plant through pre-insulated pipes. Pre-insulated pipes are in fact a modern kind of heat culvert or district heating duct, but since these systems… Read more
Mar 03, 2011 | By Edvard Csanyi
Protection
History of the development of busbar protection
Up to the mid 1930’s, no widescale efforts had been made to protect busbars on a unit basis. Also there was reluctance in arranging one protective equipment to cause simultaneous tripping of a large number of circuits. Before the British… Read more
Mar 02, 2011 | By Edvard Csanyi
Energy and Power
How to improve the power quality with harmonic filters
In electrical plants the loads draw from the network electric power (active) as power supply source (e.g. personal computers, printers, diagnostic equipment, etc.) or convert it into another form of energy (e.g. electrical lamps or stoves) or into mechanical output… Read more
Mar 01, 2011 | By Edvard Csanyi
Solar Power
What Do You Need To Know When Connecting Solar Electric System to the Utility Grid
In the past, most homes with solar electric systems were not connected to the local utility grid. It made sense to install solar electric systems in areas without easy assess to the power grid, where the option of extending a… Read more
Feb 28, 2011 | By Edvard Csanyi
Transformers
Transformer Winding Temperature Thermometer
These devices are supposed to indicate hottest spot in the winding based on the manufacturers heat run tests. At best, this device is only accurate at top nameplate rated load and then only if it is not out of calibration…. Read more
Feb 25, 2011 | By Edvard Csanyi
Metering
How To Use A Digital Multimeter
A digital multimeter is used to make various electrical measurements, such as AC and DC voltage, AC and DC current, and resistance. It is called a multimeter because it combines the functions of a voltmeter, ammeter, and ohmmeter. Multimeters may… Read more
Feb 23, 2011 | By Edvard Csanyi
Energy and Power
Protection Relay – ANSI Standards
In the design of electrical power systems, the ANSI Standard Device Numbers denote what features a protective device supports (such as a relay or circuit breaker). These types of devices protect electrical systems and components from damage when an unwanted… Read more
Feb 22, 2011 | By Edvard Csanyi
Electronics
What Is Modulation?
Modulation is the use of one electrical signal to “control” a primary variable of another. For example, if an audio signal voltage is used to control the “amplitude” of a carrier signal, the result is amplitude modulation. It is important… Read more
Feb 20, 2011 | By Sa'ad Eddin
IEC Standards
IP Protection Degree (IEC 60529) Explained
The protection of enclosures against ingress of dirt or against the ingress of water is defined in IEC529 (BSEN60529:1991). Conversely, an enclosure which protects equipment against ingress of particles will also protect a person from potential hazards within that enclosure,… Read more
Feb 19, 2011 | By Edvard Csanyi
