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. A choke coil uses this to induce current






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






3. 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.






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






5. Anything above 600 volts is _____?






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






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






8. A ___________ transformer is a continuously adjustable Autotransformer.






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






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






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






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






15. The formula for the voltage related to turns ratio






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






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






18. Divergence of the magnetic field causes this






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






20. The voltage induced in the coil is directly proportional to this






21. The 4 types of transformer cores






22. The 3 principle components of a transformer






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






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






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






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






27. Central magnetic core made of






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






29. A variable transformer is a continuously adjustable _____ - has the primary winding and secondary winding electrically connected.






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






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






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






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






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






35. A simple design has a core within each coil






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






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






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






39. 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






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






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






42. 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






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






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






45. What is a rotation meter?






46. A transformer loses less than _% in energy






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






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






49. An electromagnetic device that operates on the principle of self induction. It uses AC.






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