Air Circuit Breaker

Schneider Electric (NW&NT) air circuit breaker 

Air Circuit Breaker (ACB)

The type of circuit breaker, which operates in air (where air-blast as an arc quenching medium) at atmospheric pressure, is known to be an Air Circuit Breaker. Air circuit breaker has completely replaced by oil circuit breaker. In different countries, still it is a preferable choice to use an Air circuit breaker up to 15KV because, there is no chance of oil fire like in oil circuit breaker.

Harmonic and capacitor selection

Effects of Harmonics

Schneider Capacitor

Harmonics in electrical installation

The presence of harmonics in electrical systems means that current and voltage are distorted and deviate from sinusoidal wave forms.

Harmonic currents are currents circulating in the networks and which frequency is an integer multiple of the supply frequency.

Power Factor Correction

Improving the PF can maximize current-carrying capacity, improve voltage to equipment, reduce power losses, and lower electric bills. The simplest way to improve power factor is to add PF correction capacitors to the electrical system. PF correction capacitors act as reactive current generators. They help offset the non-working power used by inductive loads, thereby improving the power factor. The interaction between PF capacitors and specialized equipment, such as variable speed drives, requires a well-designed system.

Power Factor

Loads in electrical distributer systems are inductive Loads which need a magnetic field to operate, Such as motors, transformers, ballasts and furnace.

In first we should know what is the two kinds of power that be needed in the inductive loads;

Conductors & Stranded Types

Conductors

Conductors have the function of getting electricity from one point to another in an electrical circuit. 

Copper and aluminum are the main materials discussed because of their balance between high conductivity and reasonable price.

MCCB & Trip Unit

What is a Circuit Breaker?

Schneider Electric 

The definition of a circuit breaker varies between the standards organizations, but the most commonly used definitions are:  

Defines circuit breakers as “devices designed to open and close a circuit by non-automatic means, and to open the circuit automatically on a predetermined overcurrent without injury to itself when properly applied within its rating.

a mechanical switching device, capable of making, carrying and breaking currents under normal circuit conditions and also making, carrying for a specified time and breaking currents under specified abnormal circuit conditions such as those of short-circuit.

MCB

What is The MCB ?

Schneider Electric

The definition of MCB is Miniature Circuit Breaker . MCB is electromechanical device which is used to protect electrical circuit from the overcurent which may caused due to ( short circuit , overloads or faulty design). It interrupts the continuity of electrical flow through the circuit once a fault is detected . now we can define the MCB as a switch which automatically turns off when the current flowing through it passes the maximum allowable limit.    

Centrifugal Pumps ( Part 2)

We talk in the part one about Centrifugal Pumps . Now we complete in the second part the other Centrifugal Pumps parts.

Motor Starting Method (1- DOL Method )

When a motor is switched on , there is a high inrush current from the mains, ( The starting current of an AC motor can vary from 3 to 8 times the nominal current). The high current drawn from the network can cause problems such as voltage drop, high transients and, in

Schneider Electric DOL

some cases, uncontrolled shutdown. High starting current also causes great mechanical stress on the motor’s rotor bars and windings, and can affect the driven equipment and the foundations. Several starting methods exist, all aiming to reduce these stresses To overcome this , There are several starting systems which differ according to the motor and load specifications. The choice is governed by electrical, mechanical and economic factors. The kind of load driven is also important in the choice of starting system.