EDGE

An Overview Of Short Circuit Current (part 1) | EEP In all types of fault current there is a common element: an abnormally low-impedance path or shorted path for current to flow - short circuit current

Dry Transformer Percent Impedance Definition | EEP The percent impedance is the percent voltage required to circulate rated current flow through one winding when another winding is short-circuited

Dear All, we are Glad to announce that we are back to continue our course..

2nd Session, 6/9/2013, 10.00 PM, Center Giants.. Located in makram Ebeed at el Sallab..

You can Call the Center for more information about the location: 0222701083

For more Information, we are glad to receive your calls...

Sorry for the short notice...

Dear All, We would like to announce that we shall resume our Course Next Friday 16/8/2013 at 2.00 PM isA.. We will, Shortly, update you with more information about the Center location..

We shall also repeat the 1st session to those who didnt attend it in our Course

For more information, Our HR members will be glad to receive your Calls...

كتاب المحولات للدكتورة كاميليا
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LUMsearch - Search luminaire LUMsearch is the luminaire search engine from DIAL. Anyone- whether professional light planners, architects, interior designers or private users “ will be able to search for and find suitable luminaires.

Lighting technology: The UGR value
... is a non-dimensional index expressing the degree of direct glare from luminaires in interior locations. The UGR values are defined for the range 10 to 30, the lower this figure is, the less direct glare perceived by the observer.

Abbreviation: UGR (Unified Glare Rating).

The UGR value at a specific observer position can only be calculated mathematically, and it can neither be measured on the spot nor be defined in the form of a visual assessment.

Compliance with the UGR limit values (UGRL) is required in a number of different standards (e.g. EN 12464-1), depending on the area of activity, these being intended to define the maximum permissible glare from the lighting system affecting the observer.

DIAL perspective
The UGR value is not in any way purely a characteristic of a luminaire. The quality of glare control of a luminaire affects this value of course, however other aspects are also included in the evaluation. The observer position in the room and the observer’s typical line of vision also play a part in this because the observer cannot experience any glare if the luminaire is not in his field of vision.

A further aspect is the degree of reflectance of the room surfaces. Due to the strong contrast, a luminaire against a dark background creates a stronger glare than a luminaire positioned against a light background.

By definition it is not possible to specify a UGR value for lighting systems using luminaires that have an indirect ratio > 65% and where narrow-beam spotlights or luminaires with asymmetrical distribution are used.

According to EN 12464-1 (2011-08) light planners must provide evidence for the rating of direct glare of a lighting system by using the tabular CIE glare rating method.

This method is, however, anything but precise and quite cumbersome. First of all, the degrees of reflectance of floor, wall and ceiling underpinning this method are quite limited. For instance, according to the tabular method, the floor has a maximum degree of reflectance of 20 %. For walls it is 30% or 50% and ceiling 50% or 70%. “Normal“ white walls or ceilings as are frequently found in architecture have a degree of reflectance of approx. 75 – 90%, however.

Furthermore, the observer’s line of vision may be either transverse or longitudinal to the lamp axis. A diagonal line of vision is not taken into account here.

L-shaped or polygonal rooms are also not taken into account in the tabular method. It uses exclusively rectangular rooms as a basis.

A further disadvantage is that this method must be used for each type of luminaire individually if there are various luminaires in a room.

In practice you do not notice any visual difference between UGR values that are close together. For this reason, EN 12464-1 (2011-08) also refers to UGR steps which include a perceptible change. These steps are: 10, 13, 16, 19, 22, 25 and 28.

If a manufacturer states a precise UGR value for his product in the data sheet, this is the value that can be read from the table for degree of reflectance of 70% (ceiling), 50% (walls), 20% (floor) and the geometry of the room 4H, 8H. It should be noted that this value only applies to this specific application and does not in any way represent any “quality characteristic” of a product.

For the above reasons we recommend calculation of the UGR value with the aid of software ( e.g. DIALux). This takes into account the actual degree of reflectance and geometry of the room. In addition to this, all the luminaires in the room are included in the calculation.

Ramdan Kareeem Everyone.. :)

Electrical Interview Questions & Answers
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1-Question: How tube light circuit is connected and how it works?
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Ans :-
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A choke is connected in one end of the tube light and a starter is in series with the circuit. When supply is provided ,the
starter will interrupt the supply cycle of AC. Due to the sudden change of supply the chock will generate around 1000volts . This volt
will capable of to break the electrons inside the tube to make electron flow. once the current passes through the tube the starter circuit
will be out of part. now there is no change of supply causes choke voltage normalized and act as minimize the current.
Electrical engineering books
ahmed sayed

Offshore wind energy: TenneT awards “DolWin3”project to Alstom, marking next step in Germany’s energ Bayreuth, Berlin, Paris. Transmission System Operator TenneT has awarded the DolWin3 offshore project to Alstom. This project connects the North Sea wind farms to the mainland supergrid and has an investment volume of more than €1 billion.