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






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






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






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






5. The simplest type of transformer core






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






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






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






9. both coils in this core are heavily insulated






10. 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






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






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






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






14. What does transformer efficiency mean?






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






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






17. 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






18. The formula for the voltage related to turns ratio






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






20. Anything above 600 volts is _____?






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






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






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






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






25. 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 _____.






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






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






28. The magnetic lines of force that flow from the north pole of a magnet and return to the south pole.






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






30. 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






31. 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.






32. Copper loss is known as _____ loss.






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






34. 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)






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






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






37. 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.






38. A transformer loses less than _% in energy






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






40. The shape of the core of the transformer ensures a ______________ for the magnetic flux with maximum concentration within the core and minimum leakage of the air






41. How coercivity is minimized






42. 3 types of transformers






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






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






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






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






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






48. The 4 types of transformer cores






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






50. The 3 principle components of a transformer