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






2. The 4 types of transformer cores






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






4. both coils in this core are heavily insulated






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






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






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






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






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






10. A transformer primary (H) that has 400 turns is wound to step the voltage down from 240 volts to 120 volts. The number or turns (TX) required in the secondary (X) winding is _____.






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






12. An instrument used to measure electrical current.






13. 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






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






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






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






17. The formula for the voltage related to turns ratio






18. 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.






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






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






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






22. Transformer losses are classified as _____ and _____.






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






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






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






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






27. The simplest type of transformer core






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






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






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






31. Divergence of the magnetic field causes this






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






33. The relationship between current and voltage in the coils are inverse






34. It refers to the direction of current flow in a closed circuit.






35. The number of turns can be adjusted in these types of transformers






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






37. 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






38. has a laminated iron core (layers of metal plates)






39. A ___________ transformer is a continuously adjustable Autotransformer.






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






41. Function of the dielectric oil






42. Reference to a jumper or conductor - to or from a piece of electrical equipment.






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






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






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






46. 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.






47. _____ currents are reduced by laminating the core.






48. 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






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






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