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Posted on 4/2/2012 3:01 PM By Steven McFadyen
Anyone specifying or using electric motors should have a basic understanding how the insulation is related to temperature. Three classes of insulation are in common use (with 'F' being the most common). The image (which is form an ABB catalogue for their low voltage performance motors), shows how the installation is used in practice.
Posted on 3/29/2012 10:18 PM By Steven McFadyen
Control theory looks at how systems work and are controlled from a mathematical view. This note gives a brief introduction to some of the concepts – more of a notepad of concepts really, which can be added to over time.
Posted on 3/28/2012 10:09 PM By Steven McFadyen
Sometimes it’s useful to be able to quickly lookup a piece of technical information. This note is a collection of information related to motors, and in particular ac induction motors.
Posted on 3/28/2012 9:58 PM By Steven McFadyen
Variable frequency drives are widely used to control the speed of ac motors. This note looks at the mechanisms which enable drive units to control the speed. In addition to speed, other advantages offered by variable speed drives are investigated.
Posted on 3/28/2012 2:05 PM By Steven McFadyen
Electric motors are one of the most widely used items of electrical equipment. Improving motor efficiency benefits include, reduced power demand, lower operating costs and reduced environment impact.
In recognising the impact of motors on both power generation requirements and environmental issues, regulation in many countries now dictate efficiency limits. When specifying motors, both designers and purchasers should be concerned with efficiency performance.
Posted on 3/28/2012 1:12 PM By Steven McFadyen
Collection of links to various places with useful motor information. I’ll try and return to the page every now and again to update it with any motor notes added to the site.
Posted on 3/28/2012 1:02 PM By Steven McFadyen
Insulation on a motor prevents interconnection of windings and the winding to earth. When looking at motors, it is important to understand how the insulation functions and its practical application.
Posted on 3/28/2012 1:00 PM By Steven McFadyen
Coils of wire on the rotor carry a d.c. current which generates a magnetic field. A stator magnetic field is created using either permanent magnets or electrical field windings. Any current-carrying conductor placed within an external magnetic field experiences a force. Torque is produced in the motor by this mechanism.
Posted on 3/27/2012 4:06 PM By Steven McFadyen
We have had the Wiki with us for a long time now, but at last I have decided to say bye bye – more details on why below.
Posted on 3/25/2012 12:49 PM By Steven McFadyen
The windings of many medium and small sized transformers are protected by restricted earth fault (REF) systems. The illustration shows the principal of REF protection.
Posted on 3/24/2012 11:47 AM By Steven McFadyen
Electrical notes are a collaborative collection of electrical engineering information and educational material. Any registered user can add content.
Think of Notes as an online book; one which can be edited and expanded by our members. Everyone is encouraged to share their leaning by adding to Notes. The only requirement is that any post should be related to electrical engineering and provide educational value to our users.
Posted on 3/22/2012 11:40 AM By Steven McFadyen
The widely used United Sates standard ANSI/IEEE C37.2 'Electrical Power System Device Function Numbers, Acronyms, and Contact Designations' deals with protective device function numbering and acronyms. Even in those parts of the world where IEC standards are predominate, the use of ANSI numbering for protective device functions is still common place.