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






2. 3 types of transformers






3. 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






4. An instrument used to measure electrical current.






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






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






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






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






9. The 3 principle components of a transformer






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






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






13. Function of the dielectric oil






14. Central magnetic core made of






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






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






17. Connected to earth or to some conducting body which serves in place of the earth.






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






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






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






21. Modern; used to control filament circuit; replaced both the rheostat and choke coil; operated on the electromagnetic principle that if an iron core within or near a coil is saturated with magnetic flux by an independed source of direct current - the






22. What does transformer efficiency mean?






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






24. both coils in this core are heavily insulated






25. A simple design has a core within each coil






26. Is concentrated in the metal core






27. The current related to turns ratio law






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






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






30. A transformer rated at 500KVA and below used for voltage transformation on the distribuition system.






31. 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)






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






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






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






35. The formula for the current related to voltage law






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






37. Copper loss is known as _____ loss.






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






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






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






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






42. 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.






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






44. 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.






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






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






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






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






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






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