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. Anything above 600 volts is _____?






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






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






4. The 4 types of transformer cores






5. 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.






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






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






8. Copper loss is known as _____ loss.






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






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






11. 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






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






13. The relationship between current and voltage in the coils are inverse






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






15. Used to increase the magnetic flux in a transformer






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






17. The simplest type of transformer core






18. What does transformer efficiency mean?






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






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






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






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






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






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






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






26. 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.






27. 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.






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






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






30. 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






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






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






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






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






36. The current related to turns ratio law






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






38. 3 types of transformers






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






40. A transformer loses less than _% in energy






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






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






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






44. A single electrical circuit.






45. A simple design has a core within each coil






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






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






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






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






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