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






2. A solenoid coil is...






3. 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?






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






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






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






7. Not a symptom of electrical shock?.






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






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






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






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






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


13. A control power transformer...






14. Where should grounding resistors be located?






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






16. 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?






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






18. Not true about AC power?






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






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






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






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






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






24. The standard frequency of alternating current used at a mine is...






25. Operating coils - motors - transformers - relays and solenoids depend upon...






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






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






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






29. 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?






30. What is a capacitor?






31. 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...






32. Find the turns ratio of a single-phase transformer with the following values: Primary power of 5KW - secondary current of 100 amps - and primary voltage of 250 volts.






33. 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...






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






35. What is the danger when working around capacitors?






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






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






38. Two 10-hp induction motors are operating on 460 volts AC. One motor is connected by single- phase; the other is connected in three-phase. The three-phase will...






39. The combined capacitance of two capacitors in parallel is...






40. 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?






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






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






43. All transformers step voltage up or down by...






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






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






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






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






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






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






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