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. What is the danger when working around capacitors?






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






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






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






6. 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.






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






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






9. 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?






10. What is a capacitor?






11. 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...






12. 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...






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






14. A transformer has 1 -600 turns in the primary and 400 turns in the secondary. The primary voltage is 2 -400 volts. What is the secondary voltage?






15. High voltage is used to transmit power over long distances...






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






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






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






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






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






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






22. Current transformers - or CT's - are used to...






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






24. 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?






25. A transformer has 2000 turns in the primary and 500 turns in the secondary. The primary voltage is 3 -200 volts. What is the secondary voltage?






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






27. The primary function of a power transformer is to provide...






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






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






30. How should clothing be removed from a burn?






31. Why is 440-volt - three-phase power more commonly used in mining than 220-volt - three-phase power?






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






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






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






35. 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?






36. Define alternating current...






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






38. Not true about AC power?






39. A solenoid coil is...






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






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






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






43. 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?






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






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






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






47. 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?






48. A control power transformer...






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






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