Answer / pragathi

Transformer is a static device which transfers electrical
energy from one circuit to another circuit with out change
in frequency.

Answer / praveen kandwal

A transformer consists of an metal core of laminated sheets about 0,35mm thick insulated from each other to reduce eddy current losses. The vertical parts are called the limbs and the horizontal parts are called the yokes. The two coils are wound on the limbs. One coil is called the primary coil and the other is called the secondary coil.

The metal core is made from a ferromagnetic metal selected because of its magnetic properties
An alternating voltage applied to the primary coil results in an alternating current which produces an alternating magnetic flux in the metal core. The current /flux level is just sufficient to induce an e.m.f that is practically equal and opposite to the applied voltage. The mean path of the alternating flux . Assuming all of the flux passes through the primary and the secondary winding,it induces the same e.m.f. in each turn of both coils. Hence if N1 and N2 are the number of turns in the primary and secondary coils respectively .
When the secondary winding is in open circuit its terminal voltage is the same as the induced e.m.f . The primary current is such that the induced e.m.f is equal and opposite to the applied alternating voltage.

When a load is connected to the secondary winding a current flows. This secondary current induces a magnetic flux which tends to reduce the current flow (Lenz's Law). The induced flux tends to reduce the magnetic flux and the resulting back back e.m.f.in the primary windigs This changes the difference between the applied voltage and the back e.m.f.in the primary windings from (say 0,05% to 1%). As a result the primary current increases, by say 20 times the no-load current. The demagnetising ampere turns of the secondary winding are thus neutralised by the increase in the primary ampere turns.. As the initial no-load primary ampere-turns are very small it can be stated that

Full load Ampere-Turns on (Primary) = Full load Ampere-Turns on (Secondary)

I1.N1 = I2.N2 ..therefore I1/I2= N2 /N1 = V2 /V1


In practice the above are all approximate

Best way to measure the Soil resistance of rocky soil, three probe method and four probe method

0 Answers  

---

what is the diffrence between earth and neutral.

1 Answers  

---

sir, in a industry present pf is 0.54 pf 25hp power is there its want improve 0.9 pf. which suitable capacity capacitor is suitable please inform me.

2 Answers  

---

what is distribution board and panel board

3 Answers  

---

plz tel me syllabus and exam date 4 jr executive engg (electrical)

0 Answers   AAI Airports Authority Of India,

---

Difference B/W A/C & D/C Motors..?

10 Answers   Toyota,

---

can I connect step down transformer(25KvA,240V Phase to phase)to output of online UPS(15KvA,440V PHASE TO PHASE) Load connect to TRANSFORMER is 13KvA,240V PHASE TO PHASE. please brief if it is wrong

1 Answers   DRJ ARDE,

---

why use delta star x-mer in distribution system.

3 Answers  

---

Dear Sir I am living in Jaipur Rajasthan  now I did complete my b tech degree in electrical engineering in 2012  Sir how I gate certificate of competency for electrical supervisor

0 Answers   ONGC,

---

IF 5000amp current on LT 440V. then how much it will draw amp on HT 11KV side

10 Answers  

---

What is Antipumping Function & If we have C.T how we find the Ratio ?

0 Answers  

---

WHAT IS THE DIFFERENCE BETWEEN SHOP DRAWINGS/ DESIGN DRAWINGS AND AS BUILT DRAWINGS??

2 Answers   ACC, Al-Jaber, Dubai Group, ECEC,

---