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 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.






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






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






4. A transformer loses less than _% in energy






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






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






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






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






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






10. both coils in this core are heavily insulated






11. 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






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






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






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






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






16. Function of the dielectric oil






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






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






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






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






21. What does transformer efficiency mean?






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






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






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






25. 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.






26. 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






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






28. How coercivity is minimized






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






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






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






32. The winding to which the load is connected is called the _____ winding.






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






34. Anything above 600 volts is _____?






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






36. A single electrical circuit.






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






38. The 3 principle components of a transformer






39. The simplest type of transformer core






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






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






42. The formula for the current related to voltage law






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






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






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






46. What is a rotation meter?






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






48. 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 _____.






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






50. An instrument used to measure electrical current.