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






2. A choke coil uses this to induce current






3. Divergence of the magnetic field causes this






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






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






6. both coils in this core are heavily insulated






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






8. What is a rotation meter?






9. 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






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






11. Is concentrated in the metal core






12. Transformer losses are classified as _____ and _____.






13. 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






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






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






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






17. 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.






18. A simple design has a core within each coil






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






20. A single electrical circuit.






21. Anything above 600 volts is _____?






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






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






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






25. The 4 types of transformer cores






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






27. 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






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






29. The simplest type of transformer core






30. A magnet made by winding a coil of wire around a soft iron core. Current passed through this winding produces magnetic lines of force in the coil.






31. An instrument used to measure electrical current.






32. ___________ is often used in laminated cores - increases electrical resistance which decreases eddy currents






33. Central magnetic core made of






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






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






36. 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.






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






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






39. 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






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






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






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






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






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






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






46. 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)






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






48. Copper loss is known as _____ loss.






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






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