Transformer (12-09-21)

Transformer: It is an electrical static device that can step up & step down voltage & current without changing frequency.

                                          OR

 Electrical transformer is a static device that can   convert electrical energy from one circuit to   another circuit without any direct electrical   connection.

Transformer

Working Principle Of Transformer: 

Transformer works on Faraday's Mutual Induction.

Types of Transformer: 

1) Based on Supply

➡ Single phase transformer

➡Three phase transformer

2) Based on Winding

➡Autotransformer (single winding)

➡Two winding, Three winding, Six winding

3) Based on Construction

➡Core type

➡Shell type

4) Based on Service

➡ Distribution transformer

➡Power transformer

5) Based on Measurement

➡ Current transformer (C.T)

➡ Potential transformer (P.T)

6) Based on Function

➡ Step up transformer

➡Step down transformer

➡ Insulation transformer

7) Based on Cooling

➡Dry type transformer

➡Oil type transformer

06-07-21 DIODE

Diode:- Diode limits the current, It means that it allows electric current to go only in one direction.

It is a polarised component with two leads, called the Anode(+) & the Cathode(-). The cathode is normally marked with a Silver or colour band.

Potential Barrier:- 

1) 0.7 volts for Silicon

2) 0.3 volts for Germanium

Types of Diode:- 

1) Zener diode

2) P-N junction diode

3) Tunnel diode

4) Photo diode

5) Laser diode

6) LED 

7) PIN diode.

Uses of Diode:- Diode can be used as Rectifiers, Signal limiters, Voltage Regulators, Switches, Signal Modulators, Oscillators.

The fundamental property of a diode is its tendancy to conduct electric current in only one direction.

Diode

03-07-21 Power Factor

Power Factor (P.F):- The cosine of angle between voltage & current is called power factor.

Formula of P.F:-

P=V×I CosӨ

CosӨ=P/V.I  OR KW/KVA

Where,

P=Power in Watts

V=Voltage in Volts

I=Current in Amperes

CosӨ=Power Factor

W=Real power in Watts

VA=Apparent power in Volts-Amperes OR KVA

Types of Power Factor:-

1) Unity Power Factor

2) Lagging Power Factor

3) Leading Power Factor

Types of Electrical Load:-

 

1) Resistivity load (Unity P.F):

➡ Press, heater, incandescent bulb, water heater etc are the examples of resistivity load.

2) Inductive load (Lagging P.F):

➡ Drilling machine, table fan, water pump are the examples of inductive load.

P.F of motor in inductive load will 0.8.

3) Capacitive load (Leading P.F):

➡There is no capacitive load, usually we use capacitor for capacitive load.

Method for Improving Power Factor:-

➡APFC Panel (Maintain Near Unity P.F)

APFC→Automatic Power Factor Correction Panel

Power Factor Scale

Note:- Power Factor is only in AC & not in DC because there is no Frequency in DC.

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