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Sunday 6 August 2017

How a circuit breaker works

How a  circuit breaker works


Operation 


            All circuit breaker systems have common features in their operation. Although details vary substantially depending on the voltage class, current rating and type of the circuit breaker.

The circuit breaker must detect a fault condition; in low voltage circuit breakers this is usually done within the breaker enclosure. Circuit breakers for large currents or high voltages are usually arranged with protective relay pilot devices to sense a fault condition and to operate the trip opening mechanism. The trip solenoid that releases the latch is usually energized by a separate battery, although some high-voltage circuit breakers are self-contained with current transformers, protective relays and an internal control power source.

Once a fault is detected, the circuit breaker contacts must open to interrupt the circuit; some mechanically-stored energy (using something such as springs or compressed air) contained within the breaker is used to separate the contacts, although some of the energy required may be obtained from the fault current itself. Small circuit breakers may be manually operated, larger units have solenoids to trip the mechanism, and electric motors to restore energy to the springs.

The circuit breaker contacts must carry the load current without excessive heating, and must also withstand the heat of the arc produced when interrupting (opening) the circuit. Contacts are made of copper or copper alloys, silver alloys and other highly conductive materials. Service life of the contacts is limited by the erosion of contact material due to arcing while interrupting the current. Miniature and molded-case circuit breakers are usually discarded when the contacts have worn, but power circuit breakers and high-voltage circuit breakers have replaceable contacts.
    
miniature circuit braker
4 pole miniature circuit braker

MCCB

Tages : Working principle of circuit breaker - Use of circuit breaker- what is circuit breaker 

What is the abbreviation for ACDB

What is the abbreviation of ACDB

Abbreviation of ACDB

     ACDB - Alternating Current Distribution Board







How to work Air circuit Breaker :
https://goo.gl/g7EF1Q






DAte :06-08-2017  

Tags: Full form of ACDB - electrical engineering
Author : Basic Electrical Engineering 

What is the full meaning of mcc and mcp

What is the full meaning of mcc and mcp




MCC - Motor Control Centre

MCP - Motor Control Power

MCP- Manual call point

MCB- Miniature Circuit Breaker

MCB- Miniature circuit breaker 

Tages : Full form of - Abbreviation of mcc mcp mcb mcc

What is synchronous machine

What is synchronous machine

Synchronous Machines

    The synchronous machines are the a.c machines. The a.c producing synchronous machines are called alternating generator or alternators. As these machine produce a.c voltage commutator is absent. Another important difference between a.c. and d.c machines is that in a.c machines the field winding is on the rotor while the armature is on stator . As field winding is rotating the d.c voltage is supplied to it with the help of slip ring and brush assembly . 

abbreviation of DCDB

abbreviation of DCDB


DCDB - Direct Current Distribution Board

PDB - Power Distribution Board

PCC - Power Control Centre 

What are the types of DC Generator

What are the types of DC Generator


Depending on the method of excitation used .d.c generators are classified in two types .
       
     1. Separately excited generator 
     2. Self excited generator

Self excited generator classified in three types . 

     1. Shunt generator 
     2. Series generator
     3. Compound generator

Compound generator classified in two types 

     1. Long shunt compound generator
     2. Short shunt compound generator

What is power

Define power


Power 
     
 Power is the rate of doing work. Inotherwords power is the work done per unit time.

The unit of power is joules/sec or watts.


                   Work done
 Power        ___________
                  
                      Time

Power P = VI watts

Where 
     V = Voltage
      I = Current


Symbol = P

Si Unit = Watts 

What is the Unit of current What is the SI Unit of current

What is the Unit of current (or)What is the SI Unit of current


Current


          Symbol   =  I

          Si Unit    = ampere

           Ampere  =  (A)

principle and operation of a dc motor

principle and  operation of a dc motor


     The principle of operation of a d.c motor can be stated in a single statement as when a current carrying conductor is placed in a magnetic field it experiences a mechanical force . In a practical d.c motor field winding produces a required magnetic  field while armature conductors play a role of a current carrying conductors and hence armature conductors experience a force. As conductors are placed in the slots which are on the periphery, the individual force experienced by the conductors acts as a twisting or turning force on the armature which is called a torque. the torque is the product of force and the radius at which this force acts. So overall armature experiences a torque and starts rotating.




Basic Electrical Engineering



Tags. how works a DC motor works-working principle of  a dc motor

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How a DC motor works

How a DC motor works


       The principle of operation of a d.c motor can be stated in a single statement as when a current carrying conductor is placed in a magnetic field it experiences a mechanical force . In a practical d.c motor field winding produces a required magnetic  field while armature conductors play a role of a current carrying conductors and hence armature conductors experience a force. As conductors are placed in the slots which are on the periphery, the individual force experienced by the conductors acts as a twisting or turning force on the armature which is called a torque. the torque is the product of force and the radius at which this force acts. So overall armature experiences a torque and starts rotating.


Transformer oil testing methods

Transformer oil testing 

     1. Dissolved gas analysis
     2. Furan analysis
     3. PCB analysis
     4.General electrical & physical tests:

      a.  Color & Appearance
      b. Breakdown Voltage
      c. Water Content
      d. Acidity (Neutralization Value)
      e. Dielectric Dissipation Factor
      f. Resistivity
      g. Sediments & Sludge
      h. Flash Point
      i. Pour Point
      j. Density
      k. Kinematic Viscosity
    
  • General and physical tests - 6 month 
  • Dissolved gas analysis - yearly
  • Furan testing - once every 2 years

what is the name of the oil used in transformer?

what is the name of the oil is used in transformer?

insulating Mineral oil