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






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






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






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






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






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






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






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






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






10. The simplest type of transformer core






11. 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 _____.






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






13. 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)






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






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






16. The relationship between amperage flowing through the coils and the number of turns on individual coils is inverse






17. Current flows through the primary winding in response to primary voltage and sets up a magnetic field that varies in direction and stregnth. under the influence of the changing magnetic field an AC voltage/kv is induced across the secondary coil by e






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






19. 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






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






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






22. Copper loss is known as _____ loss.






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






24. What is a rotation meter?






25. 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






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






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






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






29. Used to increase the magnetic flux in a transformer






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






32. A ___________ transformer is a continuously adjustable Autotransformer.






33. 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






34. A single electrical circuit.






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






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






37. The formula for the current related to voltage law






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






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






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






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






42. The energy is always transferred without a change in frequency - but usually with changes in _____ and _____.






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






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






45. 3 types of transformers






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






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






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






49. An instrument used to measure electrical current.






50. The formula for the voltage related to turns ratio