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Test your basic knowledge |

Subjects : science, 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. What happens to a motor that is connected to a three-phase cable when two of the cable's leads are reversed?






2. A transformer with 3000 turns in the primary winding has a primary voltage of 4 -800 volts and a secondary voltage of 240 volts. How many turns are in the secondary winding?






3. If 13 -200 volts are measured from phase-to-phase across a wye-connected secondary - What is the phase-to-ground voltage?






4. Define alternating current...






5. The standard frequency of power supplied by the power company is...






6. Under fault conditions - the grounding resistor in a high voltage circuit limits the voltage drop in the grounding circuit external to the resistor to not more than...






7. The transformer used only to measure voltage is a...






8. Where should grounding resistors be located?






9. Which of the following does a squirrel cage induction motor have?






10. A wound-rotor induction motor has all the following EXCEPT...






11. How do you change the direction of a 3-phase AC motor?






12. A solenoid coil is...






13. AC voltage is raised or lowered by means of...






14. 460 volts AC is required to operate two motors - one connected in single-phase and the other connected in three-phase. The three-phase motor will...






15. Alternating current may be defined as...






16. The purpose of a zig-zag transformer is to...






17. If current were flowing through a grounding resistor in a 440-volt - resistance-grounded system - this would probably be because...






18. The primary leads of a single-phase transformer should be connected to the...






19. What is the first step to be followed in aiding a victim of electrical shock?






20. The minimum allowable size for trailing cables for mobile haulage equipment powered by alternating current is...






21. The most reliable method to use to determine whether or not the heart has stopped is by checking the...


22. Three-phase AC underground cables must be provided with overcurrent protection using a...






23. What type of 3-phase AC motor is used most often around a mine?






24. What value of voltage will be measured from phase-to-phase - in a wye-connected secondary - if 2 -300 volts is measured from phase-to-ground?






25. The main function of CT's and PT's on a main substation is to...






26. At what rate should mouth-to-mouth resuscitation be applied?






27. A 3-phase - 2 speed - constant torque motor is running at fast speed. The motor windings are connected wye for fast speed. Motor leads T4 - T5 and T6 are connected to the line leads. Motor leads T1 - T2 and T3 should be...






28. What is the danger when working around capacitors?






29. The following motor leads are brought out of a 3-phase motor (T1 - T2 - T3 - T4 - T5 - T6). This motor is probably for...






30. Compared to the secondary of a loaded - step-down transformer - the primary has...






31. What steps up or steps down AC voltage?






32. Surface transformer installations - unless constructed to eliminate shock hazards - must be installed at least...






33. Current in an AC circuit may be measured by...






34. If a voltmeter were placed between two phase leads of a three-phase 480-volt system - the meter would read...






35. A burn causing a blister is classified as a...






36. A current transformer has a ratio of 350:5. If the phase current is 70 amperes - what would be the secondary current?






37. What type motor is a wound-rotor induction motor?






38. Which of the following is not needed when using an ohmmeter to determine if a motor is grounded?






39. A transformer with a 1:1 ratio is usually a (an)...






40. What position of a selector switch using a voltmeter would you select to check a 120-volt AC circuit to obtain the most accurate reading?






41. Not a symptom of electrical shock?.






42. The speed of an alternating current - squirrel-cage induction motor is...






43. The property of an electrical circuit that opposes any change in voltage is called...






44. When not connected to a load - the secondary leads of a current transformer should be...






45. Using a 10:1 ratio transformer - the terminals on the secondary side or lower voltage side would be marked...






46. Compared to the secondary of a loaded - step-down transformer - the primary has...






47. The current on the primary side of a step-down transformer with a 4:1 ratio will be...






48. A control power transformer...






49. What is a capacitor?






50. A transformer has a primary voltage of 2 -400 volts and a secondary reading of 120 volts. If there are 1 -500 turns on the primary - how many turns are on the secondary?






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