Electricalunits.com

Related Topics

‣  Protection of Transformer‣  Equivalent Circuit diagram of single phase Transformer ‣  Core type Transformer and Shell type Transformer‣  Transformer with winding Resistance and Magnetic Leakage‣  Transformer with winding Resistance but No Magnetic Leakage‣  Equivalent Resistance of single phase Transformer‣  Magnetic leakage of Single Phase Transformer‣  Oil Flow Indicator of the pump of Power Transformer‣  Silica Gel Breather of Transformer‣  Oil Pump of Transformer ‣  Radiator of Transformer and working of Radiator‣  PRD of Transformer‣  MOG ( magnetic oil gauge ) of Transformer‣  Bushing of Transformer ( for H.V side and L.V side )‣  WTI and OTI of Transformer‣  Buchholz Relay of Transformer and Working of Buchholz Relay‣  Conservator tank of Transformer‣  What is a Power Transformer ?‣  Short Circuit Test or Full load Cu loss of Transformer ‣  Open circuit test or No load Test of Transformer ‣  Parallel operation of 3-phase Transformer‣  Earthing or Neutral Grounding Transformer ‣  Transformer on On load Condition ‣  What is a Transformer ?‣  E.m.f Equation of Transformer ‣  Transformer on No load Condition

Index

E.m.f Equation of Transformer

Suppose , N1 = No. of turns of primary coil &

N2 = No. of turns of secondary coil of a transformer.

Φ_m = Maximum flux in core ( webers)

= B_m x A

f= frequency of alternating current in Hz

From the figure , it has been seen that the flux Φ increases from its zero value to maximum value Φ_m in one quarter of the cycle i.e in 1/4 f second

=4 f Φ_m Wb/s or volt

Now, rate of change of flux per turn means induced e.m.f in volts.

∴ average e.m.f/ turn = 4 f Φ_m volt

If the magnitude of flux Φ varies sinusoidally, then the r.m.s value of induced e.m.f is obtained by multiplying the average value with from factor.

∴ r.m.s value of e.m.f./turn = 1.11 x 4fΦ_m = 4.44 fΦ_m volt

Now, r.m.s value of the induced e.m.f in the primary winding

∴ E₁ = (induced e.m.f/turn) x No. of primary turns

∴ E₁ = 4.44 f Φ_m N1 (As Φ_m = B_m x A )

∴ E₁ = 4.44 f N1B_m A .....................(i)

Similarly, r.m.s value of the e.m.f. induced in secondary is,

∴ E₂ = (induced e.m.f/turn) x No. of Secondary turns

= 4.44 f Φ_m N2 (As Φ_m = B_m x A )

⇒ E₂ = 4.44 f N2 B_m A .....................(ii)

It is seen from equation (i) and (ii) that E₁ / N1 = E₂ / N2 = 4.44 f Φ_{m .}

from the above equation it is seen that the e.m.f/ turn is the same in both primary and secondary windings.

.

Voltage Transformation Ratio :-

.

From equation (i) and (ii) ,we get

∴ E₁ / N1 = E₂ / N2 = 4.44 f Φ_m = K

Constant K is known as voltage transformation ratio.

i) If N2 > N1 i.e K > 1,then transformer is called step-up transformer.

ii) If N2 < N1 i.e K < 1,then transformer is called step-down transformer.

<< Previous Next >> More details go to:

electrical4u.com

electricaleasy.com

Youtube.com

wikipedia.org

Recent Post

Name :   

Comments: