Diese Präsentation wurde erfolgreich gemeldet.
Die SlideShare-Präsentation wird heruntergeladen. ×
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
Anzeige
PHYSICS PROJECT
INVESTIGATORY PROJECT
ON
“TRANSFORMER”
Guided by: - Mr.B.K. Rath (Physics department)
NAME: - ASHWINI KUMA...
Acknowledgement
I would like to extend my deepest gratitude to
Mr. B.K. Rath (Physics department) for his constant
support...
CERTIFICATE-1
This is to certify that ASHWINI KUMAR SAH of class XII-‘A’
has successfully completed his project titled –
“...
Anzeige
Anzeige
Anzeige
Nächste SlideShare
Sanjay
Sanjay
Wird geladen in …3
×

Hier ansehen

1 von 18 Anzeige
Anzeige

Weitere Verwandte Inhalte

Diashows für Sie (20)

Ähnlich wie Physics (20)

Anzeige

Aktuellste (20)

Physics

  1. 1. PHYSICS PROJECT INVESTIGATORY PROJECT ON “TRANSFORMER” Guided by: - Mr.B.K. Rath (Physics department) NAME: - ASHWINI KUMAR SAH CLASS: - XII (A) ROLL NO. :-13 SUBMITTED AS PER THE REQUIREMENT OF AISSCE- 2019-20
  2. 2. Acknowledgement I would like to extend my deepest gratitude to Mr. B.K. Rath (Physics department) for his constant support and encouragement during the making of this project. I should also not forget Mr.N.R. Pattanaik (LabAssistant) for his morale boosting words as well as his help with the laboratory apparatus during our practicals. I am also greatly thankful to our principal Dr.B.K.Mishra for his moral support and guidance. ASHWINI KUMAR SAH Class-XII(A)
  3. 3. CERTIFICATE-1 This is to certify that ASHWINI KUMAR SAH of class XII-‘A’ has successfully completed his project titled – “TRANSFORMER” under the guidance and supervision of Mr. B.K. Rath (Physics department) as a part of fulfilment for the requirement of AISSCE 2019-20. Mr.N.R. Pattanaik Mr. B.K. Rath (Lab Assistant) (Physics department) Nalco Nagar,Angul Nalco Nagar,Angul
  4. 4. EXTERNAL EXAMINER CERTIFICATE-2 This is to certify that ASHWINI KUMAR SAH of class XII-A has successfully completed his project titled – “TRANSFORMER” under the guidance and supervision of Mr. B.K. Rath of Physics department as a part of fulfilment for the requirement of AISSCE 2019-20. Dr.B.K.Mishra Principal DELHI PUBLIC SCHOOL
  5. 5. Nalco Nagar, Angul CONTENT 1. Aim of the Experiment 2. Introduction 3. Theory 4. Apparatus Required 5. Procedure 6. Efficiency 7. Energy Loses 8. Uses of the Transformer 9. Precaution 10. Source of Error 11.Conclusion 12.Bibliography
  6. 6. AIM OF THE PROJECT To investigate the relation between the ratio of- 1. Input and output voltage 2. Number of turnings in The secondary coil and the primary coil of self made transformer:
  7. 7. INTRODUCTION The transformer is a device used for converting a low alternating voltage to a high alternatingvoltage or vice-versa. A transformer is an electrical device which is used for changing the A.C. voltages. A transformer is most widely used device in both low and high current circuit. As such transformers are built in an amazing strength of sizes. In electronic, measurement and control circuits, transformer size may be so small that it weights only a few tens of grams whereas in high voltage power circuits, it may weight hundredsof tons A Transformer based on the principle of mutual induction according to this principle, the amount of magnetic flux linked with the coil changing, an emf is inducedin the neighboringcoil. In a transformer, the electrical energy transfer from one circuit to another circuit takes place without the use of moving parts A transformer which increases the voltages is called a step-up transformer. A transformer which decreases the A.C. voltages is called a step-down transformer. Transformer is, therefore, an essential piece of apparatus both for high and low current circuits.
  8. 8. THEORY When an altering emf is suppliedto the primary coil P1P2, an alternatingcurrent starts falling in it. The altering current in the primary produces a changing magnetic flux, which induces altering voltage in the primary as well as in the secondary. In a good-transformer, whole of the magnetic flux linkedwith primary is also linkedwith the secondary, then the induced emf induced in each turn of the secondary is equalto that inducedin each turn of the primary. Thus if Ep and Es be the instantaneousvalues of the emf induced in the primary and the secondary and Np and Ns, are the no. of turns of the primary secondary coilsof the transformer and dɸb/dt =rate of change of flux in each turn off the coil at this instant, we have Ep =- Np dɸb/dt ----- (1) And , Es= -Np d§b/dt ----- (2) Since the above relationsare true at every instant, so by dividing 2 by 1, we get
  9. 9. Es/ Ep= - Ns/Np --------- (3) As Ep is the instantaneousvalue of back emf inducedin the primary coil P1 , so the instantaneouscurrent in primary coil is due to the difference (E-Ep) in the instantaneousvalues of the appliedand back emf further if Rp is the resistance O, P1P2 coil, then the instantaneouscurrent lp in the primary coil is given by Ip= E- Ep /Rp E- Ep = IpRp When the resistance of the primary is small, IpRp can be neglected so therefore E – Ep = 0 or Ep =E Thus back emf = inputemf Hence equation3 can be written as Es / Ep = Es / E = output emf / input emf= Ns / Np = K Where K is constant, called turn or transformation ratio.
  10. 10. In a step up transformer Es > E, so K > 1, hence Ns > Np As k> 1, so lp>Is i.e. current in sec. is weaker when secondary voltage is higher. Hence, whatever we gain in voltage, we lose in current in the same ratio. Similarlyit can be shown, that in a step down transformer, whatever we lose in voltage, we gain in current in the same ratio.
  11. 11. Thus a step up transformer in reality steps down the current & a step down transformer step up the current. In a step down transformer Es < E so K < 1, hence Ns < Np If Ip = value of primary current at the same instant t And Is = value of sec. current at this instant, then Input power at the instant t = Eplp and Output power at the same instant = Es Is
  12. 12. If there are no losses of power in the transformer, then Input power = output power Or Ep Ip = Es IsOr Es /Ep =Ip/Is = K APPARATUS REQUIRED
  13. 13. 1. Iron rod 2. copper wire 3. voltmeter 4. ammeter PROCEDURE
  14. 14. 1. Take thick iron rod and cover it with a thick paper and wind large number of turns of thin Cu wire on thick paper (say 60). This constitutes primary coil of the transformer. 2. Cover the primary coil with a sheet of paper and wound relativelysmaller number of turns (say 20) of thick copper wire on it. Thisconstitutes the secondary coil. It is a step down transformer 3. Connect P1, P2 to A.C main and measure the input voltage and current using A.C voltmeter and ammeter respectively. 4. Similarly,measure the output voltage and current through S1 and S2. 5. Now connect S1 andS2 to A.C main and again measure voltage and current through primary and secondary coil of step up transformer 6. Repeat all steps for other self made transformers by changing number of turns in primary and secondary coil EFFICIENCY
  15. 15. Efficiency of a transformer is defined as the ratio of output power to the input power i.e. ɳ = output power / input power = Es Is / Ep lp Thus in an idealtransformer, where there is no power losses, ɳ = 1. But in actual practice, there are many power losses; therefore the efficiency of transformer is less than one. ENERGY LOSSES Followingare the major sources of energy loss in a transformer: 1. Copper loss is the energy loss in the form of heat in the copper coils of a transformer, due to joule heating of conducting wires. 2. Iron loss is the energy loss in the form of heat in the iron core of the transformer. Thisis due to formation of eddy currents in iron core. It is minimized by taking laminatedcores. 3. Leakage of magnetic flux occurs, inspite of best insulations. Therefore, rate of change of magnetic flux linked with each turn of S1 S2 is less than the rate of change of magnetic flux linkedwith each turn of P1P2 4. Hysteresis loss is the loss of energy due to repeated magnetizationand demagnetizationof the iron core when A.C. is fed to it. 5. Magneto striation i.e. humming noise of a transformer. USES OF TRANSFORMER
  16. 16.  A transformer is used in almost all a.c. operations  In voltage regulator for T.V., refrigerator, computer, air conditioneretc., in the inductionfurnaces.  A step down transformer is used for welding purposes.  A step down transformer is used for obtaininglarge current.  A step up transformer is used for the productionof X-Rays and NEON advertisement.  Transformers are used in voltage regulators and stabilized power supplies.  Transformers are used in the transmissions of a.c. over long distances.  Small transformers are used in Radiosets, telephones,loud speakers and electric bellsetc. PRECAUTIONS  Keep yourself safe from high voltage.  While taking the readingsof current and voltage the A C should remain constant. SOURCES OF ERROR  Values of current can be changed due to heating effect.  Eddy current can change the readings.
  17. 17. CONCLUSION i. The output voltage of the transformer across the secondary coil dependsupon the ratio Ns/Np with respect to the input voltage. ii. There is loss of power between input and output power of the transformer.
  18. 18. BIBLIOGRAPHY i. www.google.com ii. www.yahoo.com iii. Physics Lab Manual book- Class XII(A) iv. NCERT Physics text book- Class XII(A) v. New simplified physics book- S.L. Arora

×