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






2. What is a capacitor?






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






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






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






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






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






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






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






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






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






12. Define alternating current...






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






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






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






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






17. How should clothing be removed from a burn?






18. Not true about AC power?






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






20. Alternating current may be defined as...






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






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






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






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






25. 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...






26. 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?






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






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






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






30. What is the danger when working around capacitors?






31. What steps up or steps down AC voltage?






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






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






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






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






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






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






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






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






41. 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...






42. 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.






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






44. 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?






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






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






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






48. A control power transformer...






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






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