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






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






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






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






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






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






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






8. 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?






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






10. 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?






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






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






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






14. Not a symptom of electrical shock?.






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






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






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






18. What is the danger when working around capacitors?






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






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






21. If a voltmeter is connected between a phase lead and the ground of a three-phase 480-volt system - the meter will read...






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






23. 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?






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






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






26. 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?






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






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






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






31. How should clothing be removed from a burn?






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






33. A solenoid coil is...






34. 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?






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






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






37. What is a capacitor?






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






39. 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?






40. 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?






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






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






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






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






45. Current that changes periodically in direction is...






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






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






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






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






50. 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...