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






2. Transformer losses are classified as _____ and _____.






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






4. A choke coil uses this to induce current






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






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






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






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






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






10. The 4 types of transformer cores






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






12. A ___________ transformer is a continuously adjustable Autotransformer.






13. A simple design has a core within each coil






14. 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






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






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






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






18. both coils in this core are heavily insulated






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






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






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






22. A single electrical circuit.






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






24. 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.






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






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






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






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






29. The 3 types of transformer power loss






30. This type of core is moderately efficient due to closing the core and layering design which reduces power loss from less leakage flux which provides a continuous path for magnetic flux and an increase in field strength






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






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






33. 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.






34. 3 types of transformers






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






36. To minimize ________ in transformer construction - the primary and secondary windings are placed on the same leg(s) of the core.






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






38. 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






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






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






41. The 3 principle components of a transformer






42. Function of the dielectric oil






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






44. Central magnetic core made of






45. Two coils wound on a closed iron core form a ________.






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






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






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






49. What is a rotation meter?






50. 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.