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. What is a rotation meter?






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






3. How the voltage and the number of turns are related for the voltage related to turn ratio






4. Waste of power known as transformer loss - often produced by closed-ended core






5. 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






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






7. Transformers with 4800 volt primaries and 120/240 volt secondaries - either pole or subway type - with two secondary windings terminating at internal links which provide for parallel operation of the secondary windings at 120 volts or series operatio






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






9. Function of the dielectric oil






10. This core is more efficient than the air core because the iron core in each coil intensifies the magnetic flux in both primary and secondary coils when they become magnetized as current flows through each set of coils






11. Copper loss is known as _____ loss.






12. Is concentrated in the metal core






13. The voltage induced in the coil is directly proportional to this






14. _____ shows that the voltamperes of the primary of a transformer equal the voltamperes of the secondary of a transformer.






15. Provides the ratio between the applied primary voltage and the induced secondary voltage as result of the turns ratio






16. Used to increase the magnetic flux in a transformer






17. Modern; used to control filament circuit; replaced both the rheostat and choke coil; operated on the electromagnetic principle that if an iron core within or near a coil is saturated with magnetic flux by an independed source of direct current - the






18. Autotransformers are not safe when they supply a _____ voltage from a high voltage source.






19. _____ currents are reduced by laminating the core.






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






21. A single electrical circuit.






22. This type of transformer power loss is caused by the continually changing AC current movement which constantly magnetizes/demagnetizes/re-magnetizes






23. Anything above 600 volts is _____?






24. ___________ is often used in laminated cores - increases electrical resistance which decreases eddy currents






25. Some losses occur in all transformers. These losses are classified as copper losses and _____ losses.






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






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






28. 3 types of transformers






29. A choke coil uses this to induce current






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






31. A ___________ transformer is a continuously adjustable Autotransformer.






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






33. A transformer which when supplied from a constant potential source automatically maintans a constant current in its secondary circuit under varying conditions of load impedance. Used on series street light circuits.






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






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






36. In a transformer the _____ current will always flow in such a direction that its magnetizing action will oppose the magnetizing action of the primary winding.






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






38. closed core with a top and bottom. It directs the magnetic field towards the primary and secondary coils and increases the field stregnth






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






40. The entire transformer is placed in a metal tank then immersed in ________.






41. 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






42. Transformer losses are classified as _____ and _____.






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






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






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






46. The terminals of the high voltage winding are marked _____.






47. The formula for the current related to voltage law






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






49. A transformer loses less than _% in energy






50. An instrument used to measure electrical current.