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






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






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






4. 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






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






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






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






8. 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)






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






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






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. 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






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






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






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






16. The formula for the current related to voltage law






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






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






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






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






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






22. How coercivity is minimized






23. A simple design has a core within each coil






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






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






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






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






28. What does transformer efficiency mean?






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






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






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






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






33. Determines if the transformer is a step up or step down transformer






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






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






36. A single electrical circuit.






37. _____ currents are reduced by laminating the core.






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






39. The simplest type of transformer core






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






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






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






43. 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






44. This core is more efficient than the air core because the iron core in each coil intensifies the magnetic flux in both primary and secondary coils when they become magnetized as current flows through each set of coils






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






46. Used to increase the magnetic flux in a transformer






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






48. A choke coil uses this to induce current






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






50. both coils in this core are heavily insulated