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






2. A simple design has a core within each coil






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






4. The 3 principle components of a transformer






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






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






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






8. 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.






9. 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.






10. Central magnetic core made of






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






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






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






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






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






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






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






19. both coils in this core are heavily insulated






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






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






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






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






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






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






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






27. 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






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






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






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






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






32. Anything above 600 volts is _____?






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






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






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






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






37. 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.






38. An instrument used to measure electrical current.






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






40. 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






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






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






43. How coercivity is minimized






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






45. A transformer loses less than _% in energy






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






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






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






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. What does transformer efficiency mean?