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. When an alternating current is applied to the high-voltage (H) winding of a transformer with no load on the secondary (X) winding - a small current - called the _____ current - flows in the primary.






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






3. Transformer losses are classified as _____ and _____.






4. The simplest type of transformer core






5. How coercivity is minimized






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






7. both coils in this core are heavily insulated






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






9. The turns of both windings are cut by the same flux; therefore the induced emf in each turn of both windings is the _____.






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






11. The formula for the voltage related to turns ratio






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






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






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






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






16. A single electrical circuit.






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






18. 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






19. 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






20. 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)






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






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






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






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






25. What is a rotation meter?






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






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






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






29. The 4 types of transformer cores






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






31. An abnormal connection of relative low resistance - whether made accidentally or intentionally - between two point of different potential in a circuit.






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






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






34. _____ currents are reduced by laminating the core.






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






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






37. Copper loss is known as _____ loss.






38. Central magnetic core made of






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






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






41. A ___________ transformer is a continuously adjustable Autotransformer.






42. The 3 principle components of a transformer






43. 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






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






45. Divergence of the magnetic field causes this






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






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






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






49. Current flows through the primary winding in response to primary voltage and sets up a magnetic field that varies in direction and stregnth. under the influence of the changing magnetic field an AC voltage/kv is induced across the secondary coil by e






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