Posted on 8/28/2009 1:03 AM By Steven McFadyen
"I can live with doubt and uncertainty and not knowing. I think it is much more interesting to live not knowing than to have answers that might be wrong. If we will only allow that, as we progress, we remain unsure, we will leave opportunities for alternatives. We will not become enthusiastic for the fact, the knowledge, the absolute truth of the day, but remain always uncertain … In order to make progress, one must leave the door to the unknown ajar."
— Richard P. Feynman
Posted on 8/26/2009 11:55 PM By Steven McFadyen
The IEC publishes a series of documents and rules governing the preparation of documents, drawings and the referencing of equipment. Depending on country and industry, people are either familiar with the IEC system or not. For those not familiar it can be a little confusing at first.
Often when IEC document production is compared to methods it is mistakenly assumed the difference is simply symbols. This is not the case. The IEC document and referencing system is a comprehensive approach covering symbols, drawing and layout techniques, equipment references, identification of terminals and signals, classification of documents and computer data organisation. It also goes beyond just documentation and extends into physical devices and implementation.
Posted on 8/11/2009 2:32 AM By Steven McFadyen
Various arguments exist around SF6 Gas Insulated (GIS) and Air Insulated (AIS) medium voltage switchgear. Recently we had to change a GIS design to AIS due to an instruction from one of our clients. His concern is the global warming potential of SF6. While understanding the clients reasons, I'm not convinced on the argument.
Posted on 8/2/2009 10:50 PM By Steven McFadyen
I've been considering a blog on the 110 or 230 Volt issue for a while. While browsing the Internet I came across a great summary by Borat over at engineering.com. He summarises the issue as:
- Historical reasons. Edison insisted on 110 V (DC) but was convinced by Westinghouse to switch to AC so that transformers (step up/down) could be used. So that became the North American standard. In Europe AEG started with 110 V (following Edison) but at 50 Hz (instead of North American 60 Hz) because it fit neater into the metric system. After WWII the voltage was doubled to 220 V because higher voltages use less copper - which was at a premium. Other countries in the world usually followed the standards of their colonizing powers. The proliferation of 110 V receptacles and devices in North America prevented the doubling of voltage but that is one of the reasons your large appliances use 220-240V plugs.
Posted on 8/2/2009 4:11 AM By Steven McFadyen
I was reminded of Occam's Razor while reading a book. It's quite a simple principal of logic which has stood the test of time and is accepted as central to scientific thought. Without thinking about it I quite often apply the principals of the razor in my day to day work and it has very rarely let's me down. Ensuring you have evidence of what you are being told told and preferring simple over complicated can't be a bad thing.
Posted on 7/1/2009 3:08 AM By Steven McFadyen
The new standard IEC 61439 replaces the old 60439. Compared to the old standard, the new 61439 is a more clearly defined and takes into account the assembly of pre-tested designs. .
Some key differences are that the distinction between type tested assemblies (TTA) and partially type tested (PTTA) is gone, verifying the performance is addressed in new ways and the specification of current ratings is updated.
Posted on 6/16/2009 6:01 AM By Steven McFadyen
Nikola Tesla was born exactly at midnight on July 10, 1856 in the tiny village of Smiljan, Lika in Croatia. In his late teens, Tesla left the village to pursue a career in electrical engineering. He started attending the Austrian Polytechnic in Graz, but never graduated and cut off all ties with his friends and family shortly after the start of his third year. He disappeared for awhile and suffered a nervous breakdown before being found and convinced by his father to attend Charles-Ferdinand University in Prague. However, he stayed for only one term, leaving after his father died.
Posted on 5/11/2009 5:49 AM By Steven McFadyen
Years ago I was told that you should always try to write the best report you can. Many years later I still think on this as one of the better pieces of advice. Not only does this apply to reports, but also to drawings, proposals, project plans etc.; in fact anything which is going to be read, reviewed or seen by people.
Posted on 5/6/2009 3:29 AM By Steven McFadyen
Often us engineers get so bogged down in equations, using software, producing drawings and writing specifications that this becomes the sole focus. Good engineering design needs to go beyond the technical and look at the full picture. A good way to measure this is cost, performance and time.
Posted on 4/30/2009 12:56 AM By Steven McFadyen
It wasn't so long ago I was telling someone that I don't use rules of thumb as most things are easily calculated anyhow. As it turns out I last week I ended up using what can only be described as a rule of thumb. In deference to my change of heart here are my UPS sizing rules of thumb.
Posted on 3/29/2009 4:41 AM By Steven McFadyen
Using software in our work is essential for most of us and we are becoming even more dependant on it's use. While software is a great asset, many times using it can be more problematic than the problem it is trying to solve. To maximise the benefit of using software I have been trying to think of five general guidelines. This is my list:
Posted on 3/23/2009 2:06 AM By Steven McFadyen
I was having a conversation the other day about voltage levels. While everyone was in agreement that low voltage was 1000 V and less, there was more confusion on the terms 'Medium Voltage' and 'High Voltage'.