27-06-21 Isolator

Isolator:-  Isolator is a off load device, the isolator always works in off load condition. Isolator is a widely used device in transmission & distribution. It is connected with circuit breaker & busbar.

Isolator Symbol

Types of Isolator:- 

1) Center break isolator- 32kv to 220kv

2) Pentograph isolator- 66kv 

3) Knee isolator- 800kv (HVDC, HVAC)

Isolator

Difference Between Isolator & Circuit Breaker:-

Isolator: 

1) Off load device (No load)

2) Never sense fault

3) Manually operated

4) Cost is less

5) It is not use while current flows through the line.

Circuit Breaker:

1) On load device

2) Always sense fault & trip the circuit

3) Automatically operated device

4) Cost is more

5) It is use while current flows through the line.

24-06-21 Fuse

Fuse:- A fuse is a metal wire whose melting point is low & the conductivity is high.

Generally, when high current flows, it melts & breaks the circuit against overload & short circuit.

Fuse is a primary protection device against short circuit fault.

Benefits of fuse:- 

1) Fuse is cheapest type of protection device in an electric circuit.

2) Fuse needs zero maintenance.

3) Operation of fuse is very simple.

4) It's operation is completely automatic & requires less time as compared to circuit breaker.

Types of Fuse:-

 

1) Low Voltage Fuses

a) Rewirable fuse (kit kat)

b) Enclosed H.R.C fuse

2) High Voltage Fuses

a) Cartridge fuse

b) Liquid type fuse

Glass Fuse

Kit Kat Fuse

Why Fuse Is Connected In Phase Wire?

When fuse connected in neutral wire then excess current flows from phase wire to load (device) & return from the neutral wire then fuse blows & device will be damage, that's why Fuse always connected in phase.

23-06-21 Relay

Relay:- Relay is nothing but an electrical switching circuit.

Relay is a monitoring & sensing device.

The function of a realy is to monitor the parameters & sense any abnormalities in the circuit.

Realy control electrical circuit by opening & closing contacts in another circuit.

Relay does not trip any circuit, Relay sends a command or signal to the Circuit Breaker for tripping purpose.

Relay symbol

Types of Relay:- 

1) Electro thermal realy

2) Electro mechanical relay

3) Solid state relay

4) Hybrid relay

5) Polarized relay

6) Non polarized relay

7) Buchholz relay

Relay

22-06-21 Circuit Breaker

Circuit Breaker:- A device which can make or break the circuit manually or automatically under normal & faulty condition.

                             OR

Circuit breaker is a automatically operated electrical switch device.

It protects electrical circuit & machine through any electrical fault.                                                               

Types of Circuit Breaker:- According to Voltage Level There are Three Types,

1) Low Voltage CB:- MCB, MCCB, ELCB, ACB, RCCB. (Under 1 Kilo Voltage)

2) Medium Voltage CB:- VCB, ACB (1KV to 72KV)

3) High Voltage CB:- ABCB, OCB, SF6, VCB    (Above 72.5KV)

                                 

Circuit Breaker

19-06-21 (Importance of Ohm's Law)

 Ohm's Law According to   ElectroMagnetic Field Theory (EMFT):-

 The current density in linear conductor is   proportional to the electric field intensity,     when temperature is constant.

 Importance of Ohm's Law:-

 

         
              Voltage (V)=2V

              Current (I)=20mA➡0.02A

              Total Voltage (Vᴛ)=9V➡Vᴛ - V=9-2= 7V

              Resistance (R)=?

  

           Resistance(R)=V/I= 7/0.02= 350Ω

 

 

      

  

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18-06-21 (Ohm's law)

 Ohm's law (George Simon Ohm)

 There are 3 main quantities in electrical i.e   Voltage, Current & Resistance.

 Ohm's law formula used to   calculate relationship between voltage,   current & resistance in an electrical   circuit (V=I×R).

 

 

 Ohm's law states that:- The current   flowing to   the linear conductor is directly   proportional to   potential difference   between two ends of the conductor when   temperature remain constant.

 

 Statment 2:- The current flowing through   a conductor is directly proportional to the   voltage & inversely proportional to the   resistance.

 

 Meaning Of V=I×R:- Electrical current is   directly proportional to the voltage &   inversely proportional to the resistance.

                         V↑ I↑ & R↑ I↓

 Derivation for Ohm's Law:- 

                            R∝L

                            R∝1/A

                            R∝L/A

                            R=⍴L/A

 

 Formulas for Ohm's Law:-

        

            V=I×R,    I=V/R,    R=V/I

Basic Of Electrical Engineering

 Basic Of Electrical Engineering

* Electricity:- There is a nucleus, inside it there are protons and neutrons and outside it there is electrons orbiting us this cycle is known as electricity.

 *Current (I):- An electric current is rate of   flow of electric charge. Current always   flow   from negative to positive.

  SI Unit:- Ampere (A)

 *Voltage (V):- Voltage is the difference in   charge between two points.

 In other way, we can say that pressure   applied to flow the current.

  SI Unit:- Volt (V)

 *Resistance (R):- Resistance is the   opposition to the flow of current.

 SI Unit:- Ohm (Ω)

 *Inductance (L):- It opposes the change in   electric current.

  SI Unit:- Henry (H)

 *Capacitance (C):- It is a dielectric   medium, which used to store the electric   charge in form of DC.

 SI Unit:- Farad (F)

 *Conductor:- A substance by which       electricity can passes easily is called   conductor.

 Example:- Copper, Aluminium, Silver, Gold

 *Insulator:- A substance by which   electricity cannot passes easily is called   insulator.

 Example:- Mica, Glass, Wood, Paper