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 transformer used only to measure voltage is a...






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






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






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






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






6. 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...






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






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






9. What steps up or steps down AC voltage?






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






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






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






14. Not true about AC power?






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






16. 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?






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






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






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






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






21. 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?






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






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






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






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






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






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






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






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






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






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






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






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






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






35. 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.






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






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






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






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






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






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






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






43. 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...






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






45. Where should grounding resistors be located?






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






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






48. 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?






49. How should clothing be removed from a burn?






50. Not a symptom of electrical shock?.