From the monthly archives: November 2011

We are pleased to present below all posts archived in 'November 2011'. If you still can't find what you are looking for, try using the search box.

How to Size Power Cable Duct

By Steven McFadyen on 11/24/2011 10:09 AM

Some colleagues had an issue earlier in the week on sizing conduits to be cast in concrete for some power cables . It became clear that none of us had a clear idea on an approved method. In the end w... read more..


How to Calculate Motor Starting Time

By Steven McFadyen on 11/15/2011 2:00 PM

Request to look at induction motor starting time have come up a few times on the site. Hopefully in this post, I give you guys some idea on how to calculate this. Failing that, hopefully at least som... read more..


Difference Between Live and Dead Tank Circuit Breakers

By Steven McFadyen on 11/11/2011 10:51 AM

A quick post in connection with an email question:

Live Tank - the circuit breaker the switching unit is located in an insulator bushing which is live at line voltage (or some voltage above g... read more..


How to Size Current Transformers

By Steven McFadyen on 11/7/2011 11:48 AM

The correct sizing of current transformers is required to ensure satisfactory operation of measuring instruments and protection relays. Several methods exist to size current transformers. This note will... read more..


How to Check a Circuit is Dead

By Steven McFadyen on 11/3/2011 4:46 AM

If you want to check a circuit is dead (not live), you should always use the three point method. First check a known live circuit, then check the dead circuit and finally recheck the live circuit. Carry... read more..




Electric Motors

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...

Arc Flash Calculations

Working in the vicinity of electrical equipment poses an hazard. In addition to electric shock hazard, fault currents passing through air causes Arc Flash...

Three Phase Power Simplified

A single phase system is perhaps the most common type of system most people are familiar with. This is what people have in their homes and what appliances...

IEC 61439 Verification Methods

The (relatively new) switchgear and control gear standard, IEC 61439 'Low-voltage switchgear and controlgear assemblies' has three methods which can be...

Back to basics - the Watt (or kW)

When thinking about watts (W) or kilowatt (kW = 1000 W) it can be useful too keep in mind the fundamental ideas behind the unit. Watt is not a pure electrical...

Tip – Latitude and Longitude on Large Scale Plans

If you are working on a large plan, get the real coordinates [latitude, longitude] for two or more points and add them to the drawing. That way you can...

Restricted Earth Fault Protection

The windings of many medium and small sized transformers are protected by restricted earth fault (REF) systems. The illustration shows the principal of...

LED Replacement Light Bulb

The inventor of the first visible light-emitting diode makes history again this year as it begins to show customers a 40-watt replacement GE Energy Smart...

What is Aircraft Ground Power

Ever wondered what kind of power an aircraft uses when parked at the airport stand. Normally the aircraft generates it own power, but when parked with...

8 Motor parts and common faults

Straight forward list of some common motor faults.  If I have missed any other common faults, please take a bit of time to add them in as a comment below...

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