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






2. A variable transformer is a continuously adjustable _____ - has the primary winding and secondary winding electrically connected.






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






4. The formula for the voltage related to turns ratio






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






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






7. Anything above 600 volts is _____?






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






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






10. 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.






11. 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)






12. 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






13. The current related to turns ratio law






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






15. The 3 types of transformer power loss






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






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






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






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






20. 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






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






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






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






24. The 4 types of transformer cores






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






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






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






28. If the transformer is used as a _____ transformer - the high voltage winding is the primary.






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






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






31. The 3 principle components of a transformer






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






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






35. The simplest type of transformer core






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






37. The formula for the current related to voltage law






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






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






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






41. What does transformer efficiency mean?






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






43. What is a rotation meter?






44. A single electrical circuit.






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






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






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






48. 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 _____.






49. Central magnetic core made of






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