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






2. A transformer with 1 -500 turns in the primary winding has a primary voltage of 2 -400 volts and a secondary voltage of 120 volts. How many turns are in the secondary winding?






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






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






5. If 2000 watts is read in the primary of a single-phase transformer - What is the wattage in the secondary? (Assuming no losses.)






6. If any two-phase wires are reversed on a three-phase motor - the motor will...






7. Alternating current may be defined as...






8. Not true about AC power?






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






10. If the conductors of a balanced - three-phase circuit pass through a current transformer - how many amps will flow in the transformer?






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






12. Not a symptom of electrical shock?.






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






14. The secondary windings on a 10:1 step-down transformer will have a wire size...






15. The property of an electric circuit that opposes any change in current is called...






16. 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...






17. How can you tell if a victim receiving mouth-to-mouth resuscitation is getting air into the lungs?






18. Should a ground fault occur - what device can be installed to limit the current in the neutral of a three-phase AC system?






19. What is the danger when working around capacitors?






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






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






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






23. 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?






24. To protect against over-current in a three-phase circuit over-current protection must be provided for...






25. Not an acceptable method for the installations of surface transformers?






26. What should the duty rating of a grounding resistor be?






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






28. The size of a transformer is measured in...






29. A solenoid coil is...






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






31. When troubleshooting a circuit with a bank of capacitors - what precautions must be taken?






32. If you use a clamp-on ammeter or tong tester around all three-phase wires of an energized three- phase circuit simultaneously...






33. When connecting 3 single-phase transformers into a three-phase system - which of the following is NOT required for the single-phase transformers.






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






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






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






37. A transformer with 10 turns on the primary coil and 100 turns on the secondary is classified as...






38. A transformer has a primary voltage of 2 -800 volts and a secondary reading of 140 volts. If there are 2000 turns on the primary - how many turns are on the secondary?






39. The neutral ground-bed electrical power system of an underground mine should be separated from the lightning arrestor grounds by at least...






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






41. What steps up or steps down AC voltage?






42. Find the turns ratio of a single-phase transformer with the following values: Primary power of 10 KW - secondary current of 200 amps - and primary voltage of 250 volts.






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






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






45. 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?






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






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






48. The load to which the secondary winding of a current transformer was connected has opened. The secondary leads should be...






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






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?