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.
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..
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..
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..
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..
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..
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...
Cable insulation is used to provide electrical separation between conductors of a cable. During the historical development of cables, numerous types...
Traditionally generation of electricity has involved rotating machines to produce alternating sinusoidal voltage and current (a.c. systems). With the development...
Photovoltaic (PV) cells (sometimes called solar cells) convert solar energy into electrical energy. Every year more and more PV systems are installed...
The image (reproduced from IEC 60909) shows a typical fault in an ac system. From the illustration it can seen that there is an initial dc component ...
Induction motors are frequently used in both industrial and domestic applications. Within the induction motor, an electrical current in the rotor is induced...
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...
Three phase systems are derived from three separate windings, either connected in delta or star (wye). Each winding can be treated separately, leading...
Dielectrics (insulating materials for example) when subjected to a varying electric field, will have some energy loss. The varying electric field causes...
If your are ever called out to troubleshoot something on your electrical system, one of the first things consider is the supply voltage. You want to ensure...
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