Posted on 4/15/2012 1:55 PM By Steven McFadyen
Circuit breakers are switching devices whose primary function is to isolate parts of an electrical distribution system in the even of abnormal conditions. Abnormal conditions are generally caused by faults on a system which can lead to dangerous situations for both people and the system itself. In addition to providing system protection, circuit breakers enable parts of the electrical distribution to be isolated for operation and maintenance.
Posted on 4/15/2012 1:53 PM By Steven McFadyen
In 2011, with the introduction of it’s Panda search ranking algorithms, Google introduced tools for determining the original author of posts. The intention is to provide more relevant search content to users by linking to the original and penalising sites which duplicate content and don’t add value. At myElectrical we support the authorship tools for our Opinion and Notes posts.
Posted on 4/12/2012 1:50 PM By Steven McFadyen
From the earliest times, humans have found ways to create light. Pre-historic peoples used natural materials (moss, grass, etc.) soaked in animal fat and then ignited. Around 3000 to 4500 BC, oil lamps and then candles were invented. During the 18th and early 19th centuries, the technology of oil lamps improved and gas lighting was developed. Starting in the middle of the 19th century, electrical lighting became available with the invention of the fluorescent and incandescent lamps.
Lighting design is the field of creating light, its application and use by people. Lighting design starts by developing the objectives and then quantifying these by specifying the criteria. When looking objectives, the lighting designer will consider:
Posted on 4/9/2012 1:47 PM By Steven McFadyen
The International System of Units (abbreviated SI) is the world's most widely used system of units. The system consists of a set of units and prefixes.
Posted on 4/9/2012 7:45 AM By Steven McFadyen
IEC 60228 is the International Electrotechnical Commission's international standard on conductors of insulated cables. Among other things, it defines a set of standard wire cross-sections. In the United States, wire sizes are commonly measured in American Wire Gauge (AW).
Posted on 4/8/2012 4:36 PM By Steven McFadyen
One of the requirements to ensuring that everything works is to have equipment selected, manufactured and verified [tested] to IEC standards. Not all equipment out there meets this requirements. It is the responsibility of the engineers in the procurement and construction process to ensure that only equipment meeting these requirements is used.
If your involved in this activity you most likely already know what to do and have your own methods for approaching this issue. If your new to this or have just been tasked with verifying equipment meets requirements, hopefully this post will get you started.
Ensuring compliance is not complicated, but there are a couple of things you aware of.
Posted on 4/8/2012 1:38 PM By Steven McFadyen
A battery consists of one or more cells, each of which use stored chemical energy to produce electrical energy, There are many types of cells and these are combined in a multitude of ways to produce the many battery types in use.
Batteries are divided in to primary and secondary:
- Primary batteries – have an irreversible chemical action and can only be used once
- Secondary batteries – have a reversible chemical action and can be recharged
Posted on 4/8/2012 1:36 PM By Steven McFadyen
Various techniques exist to enable the correct selection of batteries for UPS applications. The procedure described below is one of the more common. It is also possible to use the IEEE 485 method (see link at the bottom of the page).
Posted on 4/8/2012 1:34 PM By Steven McFadyen
This article gives an introduction to IEEE 485 method for the selection and calculation of battery capacity.
Posted on 4/4/2012 1:32 PM By Steven McFadyen
When looking at the design of a lighting scheme it is useful to have an understanding on the nature of light itself and some of the basic theory associated with this. This article provides an overview of these concepts.
Posted on 4/3/2012 1:29 PM By Steven McFadyen
Alternating current (a.c.) is the backbone of modern electrical power distribution. In this article I’ll be pulling some of the more important concepts together. It is a work in progress and I’ll be adding to it bit by bit as I start closing pages down in the Wiki. Hopefully by the time the Wiki is fully depreciated, we should have a reasonable article here.
Posted on 4/2/2012 10:21 PM By Steven McFadyen
Electromechanical relays have been the traditional backbone of electrical protection systems. While over recent years these have been replaced by microprocessor based numerical devices, there are still many older electromechanical relays in service.