Posted on 1/20/2014 1:32 PM By Steven McFadyen
Modelica is an open source (free) software language for modelling complex systems. Having never used it before, I thought I would download a development platform and see how it stacked up. This is where I spent my Saturday.
Posted on 1/6/2014 1:22 PM By Steven McFadyen
When selecting a cable, the performance of the cable under fault conditions is an important consideration. It is important that calculations be carried out to ensure that any cable is able to withstand the effects of any potential fault or short circuit. This not looks at how to do this.
Posted on 11/12/2013 5:19 AM By Steven McFadyen
Dielectrics (insulating materials for example) when subjected to a varying electric field, will have some energy loss. The varying electric field causes small realignment of weakly bonded molecules, which lead to the production of heat. The amount of loss increases as the voltage level is increased. For low voltage cables, the loss is usually insignificant and is generally ignored. For higher voltage cables, the loss and heat generated can become important and needs to be taken into consideration.
Posted on 10/13/2013 11:44 PM By Steven McFadyen
When sizing cables, the heat generated by losses within any sheath or armour need to be evaluated. When significant, it becomes a factor to be considered in the sizing of cables.
This note looks at how to obtain the necessary loss factors for use within the IEC 60287 calculation. In addition, the loss factors quantify the ratio of losses in the sheath to total losses in all conductors and have application outside the IEC 60287 standard.
Posted on 10/7/2013 3:34 PM By Steven McFadyen
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Posted on 9/4/2013 3:47 PM By Steven McFadyen
Gauss's Electrical law defines the relation between charge ("Positive" & "Negative") and electric field. The law was initially formulated by Carl Friedrich Gauss in 1835.
In Gauss's law, the electric field is the electrostatic field. The law shows how the electrostatic field behaves and varies depending on the charge distribution within it. More formally it relates the electric flux [the electric field flowing from positive to negative charges] passing through a closed surface to the charge contained within the surface.
Posted on 9/4/2013 2:33 PM By Steven McFadyen
Maxwell's Equations are a set of fundamental relationships, which govern how electric and magnetic fields interact. The equations explain how these fields are generated and interact with each other, as well as their relationship to charge and current. They form the backbone of much of modern electrical and telecommunication technology and are often quoted as being the most important equations of all time.
Posted on 8/28/2013 2:17 PM By Steven McFadyen
Within Europe the European Committee for Electrotechnical Standardization (CENELEC) has standardised the both the designation and colour of cables. These are published in CENELEC document HD 361 S3:1999 "System for cable designation" and HD 308 S2: 2001
"Identification of cores in cables and flexible cords". This note provides a general overview to the harmonised system and gives some examples.
Posted on 8/21/2013 3:21 PM By Steven McFadyen
A UPS is an uninterruptible power supply. It is a device which maintains a continuous supply of electrical power, even in the event of failure of the mains (utility) supply. A UPS is installed between the mains supply and the equipment to be protected.
UPS are used to safeguard various types of equipment. One of the common uses is computers, particularly in data centres and the critical equipment of large organizations.
Posted on 7/11/2013 2:46 PM By Steven McFadyen
Photovoltaic (PV) cells (sometimes called solar cells) convert solar energy into electrical energy. Every year more and more PV systems are installed. With this growing application, it's a good idea for every practicing professional to have an understanding of the calculations associated with PV cells.
Posted on 7/4/2013 1:31 PM By Steven McFadyen
Fire resistant and fire retardant cable sheaths are design to resist combustion and limit the propagation of flames. Low smokes cables have a sheath designed to limit the amount of smoke and toxic halogen gases given off during fire situations.
Posted on 6/29/2013 8:24 PM By Steven McFadyen
Capacitors have numerous applications in electrical and electronic applications. This note examines the use of capacitors to store electrical energy. The sidebar shows details of a typical commercially available energy storage module.