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






2. A simple design has a core within each coil






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






4. Copper loss is known as _____ loss.






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






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






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






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






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






10. The formula for the current related to voltage law






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






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






13. 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)






14. The 3 principle components of a transformer






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






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






17. How coercivity is minimized






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






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






20. 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






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






22. The current related to turns ratio law






23. 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






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






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






26. A choke coil uses this to induce current






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






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






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






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






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






32. Transformer losses are classified as _____ and _____.






33. 3 types of transformers






34. The formula for the voltage related to turns ratio






35. The relationship between amperage flowing through the coils and the number of turns on individual coils is inverse






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






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






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






39. Central magnetic core made of






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






41. 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.






42. The 4 types of transformer cores






43. 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






44. 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






45. Used to increase the magnetic flux in a transformer






46. The characteristic that requires energy to carry out the constant reorientation of the magnetic dipoles in the hysteresis loss






47. The simplest type of transformer core






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






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






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