Maintenance And Troubleshooting Trivia Quiz!

64 Questions | Total Attempts: 191

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Electricity Quizzes & Trivia

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Questions and Answers
  • 1. 
    To safely check an electrical component for continuity or resistance, you would turn
    • A. 

      On the power and disconnnect at least one lead from the meter

    • B. 

      Off the power and disconnect at least one lead from the meter

    • C. 

      On the power and disconnect at least one lead from the component

    • D. 

      Off the power and disconnect at least one lead from the component

  • 2. 
    Which thermostat terminal passes power to the heat relay?
    • A. 

      R

    • B. 

      G

    • C. 

      W

    • D. 

      Y

  • 3. 
    Which thermostat terminal passes power to the indoor fan?
    • A. 

      R

    • B. 

      G

    • C. 

      W

    • D. 

      Y

  • 4. 
    Which fan circuit contacts must be closed to pass power to the fan motor?
    • A. 

      Fan realy

    • B. 

      Fan speed relay

    • C. 

      Evaporator relay

    • D. 

      Condenser relay

  • 5. 
    The three components that operate in the cooling mode are the
    • A. 

      Compressor, the evaporator, and the outdoor fan

    • B. 

      Indoor fan, the compressor, and the outdoor fan

    • C. 

      Comrpessor, the indoor fan, and the defrost cycle

    • D. 

      Outdoor fan, the indoor fan, and auxiliary heat

  • 6. 
    Most manufacturers illustrate the wiring in their equipment through the use of
    • A. 

      Pictoral and line diagrams

    • B. 

      Line and sectional diagrams

    • C. 

      Sectional and pictoral diagrams

    • D. 

      Sectional and enhanced diamgrams

  • 7. 
    You turn the indoor fan switch on a thermostat to the FAN ON position. When you do, the indoor fan motor does not come on. A possible cause of the problem is that there is
    • A. 

      Control voltage

    • B. 

      No control voltage

    • C. 

      Too much control voltage

    • D. 

      Not enough control voltage

  • 8. 
    You use your volt-ohm-milliammeter to check a transformer. You find it has an open. In this situation, the probable trouble is
    • A. 

      No control voltage

    • B. 

      A burned transformer

    • C. 

      No power to the G terminal

    • D. 

      A wire burned off the compressor

  • 9. 
    On a trouble call, you determine that voltage is present from R to Y at the thermostat but no voltage is present at the condenser contactor. In this situation, you would suspect that the
    • A. 

      R wire is broken

    • B. 

      Contacts are broken

    • C. 

      Y wire is broken

    • D. 

      R and Y wires are both broken

  • 10. 
    Which terminals would you use to determine why a thermostat does not pass power to the relays when a split-system air-conditioner unit is in the cooling mode?
    • A. 

      R, G, & W

    • B. 

      R, G, & Y

    • C. 

      V, B, & W

    • D. 

      V, B, & Y

  • 11. 
    After you have disabled a motor disconnect, you lock and tag the panel. After this, you should be sure to keep the only key
    • A. 

      At the shop

    • B. 

      On your person

    • C. 

      With your crew leader

    • D. 

      With your shop supervisor

  • 12. 
    Mechanical motor problems normally occur at the
    • A. 

      Pulley or belt drive

    • B. 

      Bearings or the shaft

    • C. 

      Pulleys or the shafts

    • D. 

      End bells or ball bearings

  • 13. 
    Most assemblies are held on the motor shaft by
    • A. 

      Setscrews

    • B. 

      Snap rings

    • C. 

      Lock pins

    • D. 

      O-rings

  • 14. 
    If the motor drive pulley and the driven pulley are out of line, strain will be imposed on the
    • A. 

      Starting circuit

    • B. 

      Fram mount

    • C. 

      Motor air system

    • D. 

      Shafts' drive mechanism

  • 15. 
    A short circuit will occur in the windings of a motor when the conductors in the windings
    • A. 

      Touch each other

    • B. 

      Expand and contract

    • C. 

      Pull apart from each other

    • D. 

      Create a high amperage draw

  • 16. 
    To check for a short circuit from a motor winding to ground, you would use
    • A. 

      A voltmeter

    • B. 

      An ohmmeter

    • C. 

      An anmeter

    • D. 

      A clamp-on meter

  • 17. 
    A run capacitor on an eletric motor is constructed as a
    • A. 

      Metal can

    • B. 

      Paper can

    • C. 

      Plastic can

    • D. 

      Bakelite iron can

  • 18. 
    A start capacitor on an eletric motor is constructed as a
    • A. 

      Wet type

    • B. 

      Dry type

    • C. 

      Round type

    • D. 

      Square type

  • 19. 
    The motor problems that can occur inside a hermetic compressor are
    • A. 

      A blown fuse, closed circuit, and grounded circuit

    • B. 

      A closed circuit, short circuit, and a blown fuse

    • C. 

      A grounded circuit, closed circuit, and a short circuit

    • D. 

      An open circuit, short circuit, and grounded circuit

  • 20. 
    A motor that has a bad run capacitor
    • A. 

      Will not start

    • B. 

      May run at normal speed

    • C. 

      May run at a lower-than-normal speed

    • D. 

      Will run at a higher-than-normal speed

  • 21. 
    What type of electrical problems will a hermetic compressor have?
    • A. 

      Open circuit

    • B. 

      Short circuit

    • C. 

      Grounded circuit

    • D. 

      All of the above

  • 22. 
    A single-phase condition in a three-phase motor can be caused by
    • A. 

      A defective start capacitor

    • B. 

      A burned motor

    • C. 

      A blown fuse

    • D. 

      A closed circuit

  • 23. 
     What is the possible cause when a motor will not start, hums and trips on overload?
    • A. 

      Incorrect overload switch

    • B. 

      Open disconnect switch

    • C. 

      Incorrect power supply

    • D. 

      Open fuse or breaker

  • 24. 
    The temperature range of a refrigeration system depends upon the
    • A. 

      Product being refrigerated

    • B. 

      Condensing temperature

    • C. 

      Size of the compressor

    • D. 

      Ambient temperature

  • 25. 
    To maintain 75 percent humidity in a refrigeration system with a temperature range of 25 to 45*F, the appropriate coil-to-air temperature would be
    • A. 

      8 to 12*F

    • B. 

      10 to 14*F

    • C. 

      12 to 16*F

    • D. 

      16 to 22*F

  • 26. 
    The box temperature for high-temperature refrigeration system start at
    • A. 

      30*F

    • B. 

      45*F

    • C. 

      50*F

    • D. 

      65*F

  • 27. 
    When the compressor is off and the system is up to the highest point of its operating range, the evaporator coil pressure should correspond to the
    • A. 

      Compressor pressure

    • B. 

      Condenser pressure

    • C. 

      Air tmeperature in the box

    • D. 

      Air temperature at the condenser

  • 28. 
    When the temperature of a refirgerateed space goes down, the compressor will have
    • A. 

      Less capacity because the suction gas gets thinner

    • B. 

      More capacity because the suction gas gets thinner

    • C. 

      Less capacity because the suction gas gets more dense

    • D. 

      More capacity because the suction gas gets more dense

  • 29. 
    What condensing temperature is normally maintained to obtain adequate pressure drops across an expansion valve?
    • A. 

      95*F

    • B. 

      105*F

    • C. 

      115*F

    • D. 

      125*F

  • 30. 
    What is the normal temperature difference between the inlet and the outlet water on s wastewater water-cooled condenser?
    • A. 

      25*F

    • B. 

      20*F

    • C. 

      15*F

    • D. 

      10*F

  • 31. 
    What is the most likely problem if the temperature difference between the inlet and the outlet water in a water-cooled is lower than normal?
    • A. 

      Ther water flow is sifficient

    • B. 

      There is too much water flow

    • C. 

      There is not enough water flow

    • D. 

      The cooling tower fan just cycled on

  • 32. 
    What is the normal maximum reduction of temperature in a cooling tower water if the ambient wet-bulb temperature is 85*F?
    • A. 

      72*F

    • B. 

      75*F

    • C. 

      78*F

    • D. 

      81*F

  • 33. 
    What conditions are an indication of an overcharge in a system that is not equipped with an automatic expansion valve?
    • A. 

      Low suction pressure and high discharge pressure

    • B. 

      High suction pressure and low discharge pressure

    • C. 

      Low suction pressure and low discharge pressure

    • D. 

      High suction pressure and high discharge pressure

  • 34. 
    The most probable causes of an inefficient evaporator are
    • A. 

      A dirty coil and a fan running too slow

    • B. 

      A dirty coil and a high suction pressure

    • C. 

      Too much airflow and a high suction pressure

    • D. 

      Too much airflow and a fan running too slow

  • 35. 
    What conditions are an indication of a low charge in a system that is not equipped with an automatic expansion valve?
    • A. 

      Low suction pressure and high discharge pressure

    • B. 

      High suction pressure and low discharge pressure

    • C. 

      Low suction pressure and low discharge pressure

    • D. 

      High suction prssure and high discharge pressure

  • 36. 
    If the condenser in a refrigeration system cannot remove the heat from the refrigerant, the
    • A. 

      Suction pressure will decrease

    • B. 

      Discharge pressure will increase

    • C. 

      Liquid-line temperature will decrease

    • D. 

      Suction line will frost back to the compressor

  • 37. 
    When a partial restriction occurs in the liquid line, the point of the restriction will act like
    • A. 

      An evaporator

    • B. 

      A condenser

    • C. 

      A compressor

    • D. 

      An expansion device

  • 38. 
    A compressor that is not pumping to full capacity will have
    • A. 

      High suction and low head pressure

    • B. 

      High suction and high heah pressure

    • C. 

      Low suction and low head pressure

    • D. 

      Low suction and high head pressure

  • 39. 
    You have removed and recovered the refrigerant from a system and solder repaired a leak. Before you recharge the unit, you must first perform
    • A. 

      A 4-hour standing vacuum test

    • B. 

      An operational test of the system

    • C. 

      Recurring maintenance

    • D. 

      A leak check

  • 40. 
    Calculate the discharge pressure for an R–502 system operating at 95*F outside ambient temperature.  
    • A. 

      95*F + 15*F = 110*F and 245 psig

    • B. 

      95*F + 20*F = 115*F and 265 psig

    • C. 

      95*F + 25*F = 120*F and 286 psig

    • D. 

      95*F + 30*F = 125*F and 301 psig

  • 41. 
    • A. 

      Defrost is terminated by the time clock.

    • B. 

      The unit operates with excessive head pressure

    • C. 

      The unit operates with excessive suction pressure.

    • D. 

      Manually initiated defrost is terminated by the temperature sensing device

  • 42. 
    Which is designed to stop the defrost cycle of a low-temperature walk-in?
    • A. 

      Low-pressure motor control

    • B. 

      High-pressure safety switch.

    • C. 

      Termination switch.

    • D. 

      Oil pressure switch.

  • 43. 
    When the thermal bulb of an expansion valve is loose from the suction line, you would expect the
    • A. 

      Suction line to be warmer than normal

    • B. 

      Suction line to be colder than normal

    • C. 

      Discharge line to be warmer than normal.

    • D. 

      Discharge line to be colder than normal

  • 44. 
    What problems can a high-efficiency water filtration system cause for an ice machine?
    • A. 

      None, these systems are mandatory.

    • B. 

      The system can increase the conductivity of the water.

    • C. 

      The system can decrease the conductivity of the water.

    • D. 

      None, these systems do not change the conductivity of water and cause no problems.

  • 45. 
    A refrigerator may have condensation (sweat) on the outside of the cabinet if the
    • A. 

      Mullion heater is defective.

    • B. 

      Defrost time clock is defective

    • C. 

      Defrost termination switch is defective.

    • D. 

      Evaporator fan motor is defective

  • 46. 
    When an exact replacement compressor for a refrigerator cannot be obtained, you would gather all data from the
    • A. 

      Compressor nameplate only

    • B. 

      Refrigerator nameplate only.

    • C. 

      Refrigerator nameplate and draw a diagram of the compressor lines and mounting

    • D. 

      Compressor nameplate and draw a diagram of the compressor lines and mounting

  • 47. 
    You should never use hand tools in a
    • A. 

      Hot electrical panel

    • B. 

      Cold electrical panel

    • C. 

      Cold package air conditioner

    • D. 

      Hot package air conditioner

  • 48. 
    You can reduce the danger involved in attaching high-pressure gauges on a manifold by stuttin off the
    • A. 

      Refrigerant and allow to cool

    • B. 

      High side and allowing the pressures to equalize

    • C. 

      Valves and allowing the pressures to equalize

    • D. 

      Unit an allowing the pressures to equalize

  • 49. 
    To verify that the refrigerant is boiling at the correct temperature for the low side of the system at a given load condition, you would use
    • A. 

      The high-side gauge readings

    • B. 

      The low-side gauge readings

    • C. 

      Ultralow pressure gauge readings

    • D. 

      All of the above

  • 50. 
    To check the relationship of the condensing refrigerant to the ambient air temperature, you would use
    • A. 

      The high-side gauge readings

    • B. 

      The low-side gauge readings

    • C. 

      Ultralow pressure gauge readings

    • D. 

      All of the above

  • 51. 
    If there is an internal refrigerant leak from the high-pressure side to the low-pressure side of a system, the discharge gas temperature will
    • A. 

      Equalize to the system

    • B. 

      Stay the same

    • C. 

      Go down

    • D. 

      Go up

  • 52. 
    What method would you use to measure the amount of refrigerant in a condenser?
    • A. 

      Superheat method

    • B. 

      Supercooling method

    • C. 

      Subcooling method

    • D. 

      Condensing method

  • 53. 
    You are preparing to troubleshoot a system for an electrical problem. Before you start to troubleshoot the components, you would verify that the
    • A. 

      Power supply is energized and the voltage is correct

    • B. 

      Connections are mechanically and electrically sound

    • C. 

      Contacts on all relays are clean and free to move

    • D. 

      Wires are all electrically insulated and tight

  • 54. 
    You make a continuity check on a compressor. The check indicates that the common circuit in the compressor is open. You feel the compressor dome and it is very hot. In this situation, you would suspect that the
    • A. 

      Capacitor is open

    • B. 

      Run windings are open

    • C. 

      Start windings are open

    • D. 

      Internal overload protector is open

  • 55. 
    You are troubleshooting a compressor that repeatedly trips the circuit breaker. The most likely problem is that the compressor motor
    • A. 

      Has an open winding

    • B. 

      Has a grounded winding

    • C. 

      Centrifugal switch is open

    • D. 

      Centrifugal switch is closed

  • 56. 
    The function of the indoor coil on a heat pump unit is to
    • A. 

      Be a condenser in summer and an evaporator in winter

    • B. 

      Be an evaporator in summer and a condenser in winter

    • C. 

      Act only as an evaporator

    • D. 

      Act only as a condenser

  • 57. 
    When does the outdoor unit on a heat pump act as an evaporator?
    • A. 

      Fall

    • B. 

      Spring

    • C. 

      Summer

    • D. 

      Winter

  • 58. 
    What is used to supplement the unit when the outdoor temperature drops to a point where the heat pump becomes inefficient?
    • A. 

      Auxiliary refrigerant

    • B. 

      Auxiliary forced air

    • C. 

      Auxiliary heat

    • D. 

      All of the above

  • 59. 
    What type of switch is used to prove there is water flow in both the chilled-water and condenser water circuits?
    • A. 

      Flow

    • B. 

      Pressure

    • C. 

      Water-sending

    • D. 

      Velocity-sending

  • 60. 
    Before you start a reciprocating chiller, you must ensure that the oil level is at
    • A. 

      One-eighth to one-fourth of the sight glass

    • B. 

      One-fourth to three-fourths of the sight glass

    • C. 

      One-fourth to one-half of the sight glass

    • D. 

      Three-fourths to one-half of the sight glass

  • 61. 
    Before you start the compressor on a centrifugal chiller, you must verify there is oil pressure.  To do this, you would start the oil
    • A. 

      Pump in manual

    • B. 

      Sump in manual

    • C. 

      Pump in auto

    • D. 

      Sump in auto

  • 62. 
    An oil sample from the crankcase of a centrifugal compressor should be sent to an oil laboratory on
    • A. 

      A monthly basis

    • B. 

      A quarterly basis

    • C. 

      A semiannual basis

    • D. 

      An annual basis

  • 63. 
    After you have cleaned the tubes in a condenser, how would you check their condition for defects?
    • A. 

      Pressure test

    • B. 

      Water flow test

    • C. 

      Eddy-current check

    • D. 

      Megger current check

  • 64. 
    What should be done to water chillers during the winter?
    • A. 

      Completely filled with antifreeze

    • B. 

      Completely filled with water

    • C. 

      Completely drained

    • D. 

      All of the above