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






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






3. A simple design has a core within each coil






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






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






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






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






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






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






10. Copper loss is known as _____ loss.






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






12. 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






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






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






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






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






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






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






19. An instrument used to measure electrical current.






20. 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.






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






22. A transformer loses less than _% in energy






23. 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 _____.






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






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






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






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






28. Transformer losses are classified as _____ and _____.






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






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






31. 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.






32. 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.






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






34. The transformer winding to which the load is connected is called the _____ winding.






35. The formula for the current related to voltage law






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






37. 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)






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






39. 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.






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






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






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






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






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






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






46. 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.






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






48. both coils in this core are heavily insulated






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






50. 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