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. 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






2. A single electrical circuit.






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






4. The output side it develops AC by electromagnetic mutual induction - Secondary voltage is induced in this coil






5. Function of the dielectric oil






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






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






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






9. Modern; extremely efficient-more effective coupling between primary and secondary coils; smaller and lighter






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






11. Divergence of the magnetic field causes this






12. The 4 types of transformer cores






13. The volt-amperes of the primary of a transformer is equal to the _____ - _____ output of the transformer.






14. _____ currents are reduced by laminating the core.






15. How coercivity is minimized






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






17. both coils in this core are heavily insulated






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






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






20. If the transformer is used as a _____ transformer - the low voltage winding is the primary.






21. An instrument used to measure electrical current.






22. Hysteresis Loss can be reduced by using a core with this feature






23. The 3 principle components of a transformer






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






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






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






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






28. 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






29. A transformer loses less than _% in energy






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






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






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






33. The current flowing through the primary winding - in response to the applied primary voltage - sets this up






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






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






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






37. Is concentrated in the metal core






38. A test instrument used to indicate low voltage potentials in the range of 110 to 600 volts either alternating or direct current. (slang term: wiggy)






39. What is a rotation meter?






40. _____ shows that the voltages across the windings of a transformer are directly proportional to the turns in each winding.






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






42. 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.






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






44. A designated limit of operating characteristics based on definite conditions.






45. The winding of a transformer to which electrical energy is supplied.






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






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






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






49. 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.






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