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






2. The 3 types of transformer power loss






3. An instrument used to measure electrical current.






4. A choke coil uses this to induce current






5. closed core with a top and bottom. It directs the magnetic field towards the primary and secondary coils and increases the field stregnth






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






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






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






9. 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.






10. Central magnetic core made of






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






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






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






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






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






16. 3 types of transformers






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






18. 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






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






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






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






22. 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.






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






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






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






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






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






28. What is a rotation meter?






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






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






31. Divergence of the magnetic field causes this






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






33. both coils in this core are heavily insulated






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






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






36. Is concentrated in the metal core






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






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






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






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






41. The turns of both windings are cut by the same flux; therefore the induced emf in each turn of both windings is the _____.






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






43. 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.






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






45. The current related to turns ratio law






46. If the transformer is used as a _____ transformer - the low voltage winding is the primary.






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






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






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






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