Selecting AC induction motors for cement plant applications
This technical article relies on the great paper written by Barton J. Sauer (Siemens Energy & Automation) which goes into essence of selecting the proper AC motor for cement plant… Read more
Jun 18, 2014 | By Edvard

Why is continuous on-line monitoring of partial discharge in the switchgear necessary?
Not sure? You know that periodical maintenance test like partial discharge test can still leave switchgear in virtually unknown condition. Insulation defects and deterioration may very well develop in service… Read more
Jun 16, 2014 | By Edvard

An Example Of Transformer Tap-Changer Correct Adjustment
A 13800V/4160 V transformer has five taps on the primary winding giving -5%, -2 1/2 %, nominal, +2 1/2 % and +5 % turns. If, on-load, the secondary voltage reduces… Read more
Jun 13, 2014 | By Edvard

How to mitigate effects of very fast transients (VFT) on HV equipment
The level reached by very fast transients (VFT) overvoltages originated by disconnector switching or line-to-ground faults inside a gas insulated switchgear (GIS) are below the basic insulation level (BIL) of… Read more
Jun 11, 2014 | By Edvard

How to measure insulation resistance of a motor
If the motor is not put into operation immediately upon arrival, it is important to protect it against external factors like moisture, high temperature and impurities in order to avoid… Read more
Jun 09, 2014 | By Edvard

6 Factors Influencing Requirements for a Good Grounding System
In an industrial plant or other facility that requires a grounding system, one or more of the following must be carefully considered (refer to Figure 1 below): Limiting to definite… Read more
Jun 06, 2014 | By Edvard

PLC application for reduced voltage-start motor control
Figure 1 shown below illustrates the control circuit and wiring diagram of a 65% tapped, autotransformer, reduced-voltage-start motor control circuit. This reduced voltage start minimizes the inrush current at the start… Read more
Jun 04, 2014 | By Edvard

It can happen to experienced engineers too. Stay carefull.
The effect of electricity on the body depends on the amount of current and the length of time the body is exposed to it. The higher the current, the less… Read more
Jun 02, 2014 | By Edvard

Main short circuit faults occurring in networks and machines
Short-circuits can be defined according to three main characteristics: They may be mechanical: breakdown of conductors or accidental electrical connection between two conductors via a foreign body such as a tool… Read more
May 30, 2014 | By Edvard

Generating Electricity with Combustion Turbines
There are two basic types of combustion turbines (CTs) other than the microturbines: The heavy frame industrial turbines and The aeroderivative turbines. The heavy frame systems are derived from similar… Read more
May 28, 2014 | By Edvard

A transformer is only as strong as its weakest link
Capacity (or rating) of a transformer is limited by the temperature that the insulation can tolerate. Ratings can be increased by reducing core and copper losses, by increasing the rate… Read more
May 26, 2014 | By Edvard

The role of medium voltage switchgear in power system
Most electrical appliances used in household, commercial and industrial applications work with low voltage. High voltage is used not only to transmit electrical energy over very large distances, but also… Read more
May 23, 2014 | By Edvard

Arriving at the scene of a pole fire. What to do?
Utility pole fires are common and should be treated with great respect by firefighters. Pole fires are normally caused by the failure of insulators, switches, catastrophic failure of transformers or… Read more
May 21, 2014 | By Edvard

Instrument transformers (CTs, VTs) in the system
The three main tasks of instrument transformers are: To transform currents or voltages from a usually high value to a value easy to handle for relays and instruments. To insulate the… Read more
May 19, 2014 | By Edvard

The most common accessories you can find on oil filled transformer
Every oil filled transformer has a variety of accessories for different purposes. Here, I’ll try to name the most common of them, together with picture and description. Note that pictures… Read more
May 16, 2014 | By Edvard
