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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. 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?






3. Not true about AC power?






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






5. 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?






6. Where should grounding resistors be located?






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






8. Not a symptom of electrical shock?.






9. A solenoid coil is...






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






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






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






13. 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...






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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






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


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






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






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






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






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






42. 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...






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






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






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






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






47. 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?






48. 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.






49. What is a capacitor?






50. The transformer used only to measure voltage is a...






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