Test your basic knowledge |

Transformers

Subject : engineering
Instructions:
  • Answer 50 questions in 15 minutes.
  • If you are not ready to take this test, you can study here.
  • Match each statement with the correct term.
  • Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Waste of power known as transformer loss - often produced by closed-ended core






2. Copper loss is known as _____ loss.






3. The relationship between amperage flowing through the coils and the number of turns on individual coils is inverse






4. How coils serve as the primary and secondary windings for an autotransformer






5. The winding to which voltage is supplied is called the _____ winding.






6. The input side that attaches to the AC supply it recieves the electrical energy or incoming voltage






7. For a step up and step down transformer if the turns ratio is constant this is the only way to change the output voltage






8. A transformer rated at 500KVA and below used for voltage transformation on the distribuition system.






9. The loss of power required to reverse the core magnatism each time the current reverses. This loss is caused by friction between the molecules of iron as these particles are aligned first in one direction and the in the opposite direct as current dir






10. Transformers designed for 4800 volt primary operation - but the secondaries are connected 240/480 volts. Winding ratio is 10:1






11. The 3 types of transformer power loss






12. The turns ratio between the windings (primary & secondary) of a transformer unless otherwise specified.






13. Instrument transformers reduce high voltages and currents to safe - usable values for the operation of _____ equipment.






14. A large amount of power wasted with the open-ended core






15. An electromagnetic device that operates on the principle of self induction. It uses AC.






16. The characteristic that requires energy to carry out the constant reorientation of the magnetic dipoles in the hysteresis loss






17. Central magnetic core made of






18. The 3 principle components of a transformer






19. Refers to the transformer's ability to avoid power loss (heat)






20. Anything above 600 volts is _____?






21. The energy is always transferred without a change in frequency - but usually with changes in _____ and _____.






22. The total numbre of lines or force issuing from a pole. (north or south)






23. A magnetic field changing with respect to the conductor will generate a _____ in the conductor.






24. Current flows through the primary winding in response to primary voltage and sets up a magnetic field that varies in direction and stregnth. under the influence of the changing magnetic field an AC voltage/kv is induced across the secondary coil by e






25. A stationary device for transferring alternating current electrical energy from one circuit to another circuit by electromagnetic means.






26. A transformer is a device that has no moving parts and that transfers energy from one circuit to another by _____.






27. A partial or total local failure in the insulation or continuity of a conductor.






28. How coercivity is minimized






29. Determines if the transformer is a step up or step down transformer






30. The output which can be delivered for the time specified at rated secondary voltage and rated frequency without exceeding the specified temperature limitations.






31. A system of conductors in which at least one conductors or point (usually the middle wire or neutral point of a transformer or generator windings) is intentionally grounded either solididly or through a current-limiting device.






32. Instrument transformers reduce high voltages and currents to safe - usable values for the operation of _____ _____.






33. A single electrical circuit.






34. The output rating of a transformer is based upon the maximum _____ the transformer is capable of carrying without exceeding a certain temperature rise.






35. To prevent injury to personnel when servicing any equipment connected to a current transformer - the secondary winding must be ____ - _____.






36. A magnet made by winding a coil of wire around a soft iron core. Current passed through this winding produces magnetic lines of force in the coil.






37. How a variable degree of core saturation is accomplished in a saturable reactor?






38. The shape of the core of the transformer ensures a ______________ for the magnetic flux with maximum concentration within the core and minimum leakage of the air






39. Defined as the ratio of the power output to the power input (in a closed circuit containing resistance)






40. The transformer winding to which the load is connected is called the _____ winding.






41. The magnetic lines of force that flow from the north pole of a magnet and return to the south pole.






42. Insulated primary and secondary coils are in close proximity to each other - no iron core and very innefficient






43. The winding to which the load is connected is called the _____ winding.






44. The transformer winding to which voltage is supplied is called the _____ winding.






45. Both the primary and secondary coils in a transformer are arranged around this






46. Core losses are _____ loss and _____ - _____ loss.






47. With no load on the secondary winding - a small current flows in the primary called _____ _____.






48. Kind of wire is the secondary coil in a transformer






49. Connected to earth or to some conducting body which serves in place of the earth.






50. This is the most advanced and most efficient type of tansformer; it is commonly used in x-ray equipment