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 formula for the voltage related to turns ratio






2. Used to increase the magnetic flux in a transformer






3. A single electrical circuit.






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






5. In a transformer the _____ current will always flow in such a direction that its magnetizing action will oppose the magnetizing action of the primary winding.






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






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






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






9. 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






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






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






12. 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






13. The 3 principle components of a transformer






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






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






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






17. Divergence of the magnetic field causes this






18. 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.






19. Anything above 600 volts is _____?






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






21. The 3 types of transformer power loss






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






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






24. Copper loss is known as _____ loss.






25. Function of the dielectric oil






26. An instrument used to measure electrical current.






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






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






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






30. The 4 types of transformer cores






31. How coercivity is minimized






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






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






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






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






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






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






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






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






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






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






42. What does transformer efficiency mean?






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






44. A ___________ transformer is a continuously adjustable Autotransformer.






45. The current related to turns ratio law






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






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






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






49. Core losses are _____ loss and _____ - _____ loss.






50. The formula for the current related to voltage law