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






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






3. The formula for the voltage related to turns ratio






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






5. 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.






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






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






8. An instrument used to measure electrical current.






9. 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)






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






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






12. A simple design has a core within each coil






13. _____ currents are reduced by laminating the core.






14. The 4 types of transformer cores






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






16. What is a rotation meter?






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






18. A transformer is a device that either increases or decreases alternating current and voltage using this principle






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






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






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






22. The capacity of a transformer is rated in ____ _____.






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






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






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






26. 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.






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






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






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






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






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






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






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






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






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






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






37. 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.






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






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






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






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. A transformer loses less than _% in energy






43. A part of a circuit made of a low melting point material so that it will melt and break the circuit when a specified current exceeded. Always the weakest point in the circuit.






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






45. How coercivity is minimized






46. Copper loss is known as _____ loss.






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






48. The 3 principle components of a transformer






49. A ___________ transformer is a continuously adjustable Autotransformer.






50. 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 _____.