3e151: Electrical Safety Hardest Trivia Questions! Quiz

1. You should never use hand tools in a...

Hot electrical panel.

Cold electrical panel.

Cold package air conditioner.

Hot package air conditioner.

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

No control voltage.

A burned transformer.

No power to the G terminal.

A wire burned off the compressor.

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

At the shop.

On your person.

With your crew leader.

With your shop supervisor.

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

Starting circuit.

Frame mounts.

Motor air system.

Shafts' drive mechanism.

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

An evaporator.

A condenser.

A compressor.

An expansion device.

6. Which fan circuit contacts must be closed to pass power to the fan motor?

Fan relay

Fan speed relay

Evaporator relay

Condenser relay

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

Flow.

Pressure.

Water-sending.

Velocity-sending.

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

Pump in manual.

Sump in manual.

Pump in auto.

Sump in auto.

9. What should be done to water chillers during the winter?

Completely filled with antifreeze.

Completely filled with water.

Completely drained.

All of the above.

10. Mechanical motor problems normally occur at the...

Pulley or belt drive.

Bearings or the shaft.

Pulleys or the shafts.

End bells or ball bearings.

11. Most assemblies are held on the motor shaft by...

Setscrews.

Snap rings.

Lock pins.

O-rings.

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

Low suction pressure and high discharge pressure.

High suction pressure and low discharge pressure.

Low suction pressure and low discharge pressure.

High suction pressure and high discharge pressure.

13. The most probable causes of an inefficient evaporator are...

A dirty coil and a fan running too slow.

A dirty coil and a high suction pressure.

Too much airflow and a high suction pressure.

Too much airflow and a fan running too slow.

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

A voltmeter.

An ohmmeter.

An ammeter.

A clamp-on ammeter.

15. Which thermostat terminal passes power to the heat relay?

R

G

W

Y

16. Most manufacturers illustrate the wiring in their equipment through the use of...

Pictorial and line diagrams.

Line and sectional diagrams.

Sectional and pictorial diagrams.

Sectional and enhanced diagrams.

17. 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...

Control voltage.

No control voltage.

Too much control voltage.

Not enough control voltage.

18. The motor problems that can occur inside a hermetic compressor are...

A blown fuse, closed circuit, and grounded circuit.

A closed circuit, short circuit, and a blown fuse.

A grounded circuit, closed circuit, and a short circuit.

An open circuit, short circuit, and grounded circuit.

19. 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...

R wire is broken.

Contacts are broken.

Y wire is broken.

R and Y wires are both broken.

20. A motor that has a bad run capacitor.

Will not start.

May run at normal speed.

May run at a lower-than-normal speed.

Will run at a higher-than-normal speed.

21. 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 4-hour standing vacuum test.

An operational test of the system.

Recurring maintenance.

A leak check.

22. To safely check an electrical component for continuity or resistance, you would turn...

On the power and disconnect at least one lead from the meter.

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

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

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

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

The water flow is sufficient.

There is too much water flow.

There is not enough water flow.

The cooling tower fan just cycled on.

24. The function of the indoor coil on a heat pump unit is to...

Be a condenser in summer and an evaporator in winter.

Be an evaporator in summer and a condenser in winter.

Act only as an evaporator.

Act only as a condenser.

25. When does the outdoor unit on a heat pump act as an evaporator?

Fall.

Spring.

Summer.

Winter.

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

Compressor nameplate only.

Refrigerator nameplate only.

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

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

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

Touch each other.

Expand and contract.

Pull apart from each other.

Create a high amperage draw.

28. Calculate the discharge pressure for an R-502 system operating at 95°F outside ambient temperature.

95°F + 15°F = 110°F and 245 psig.

95°F + 20°F = 115°F and 265 psig.

95°F + 25°F = 120°F and 286 psig

95°F + 30°F = 125°F and 301 psig

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

Low-pressure motor control.

High-pressure safety switch.

Termination switch.

Oil pressure switch.

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

Auxiliary refrigerant.

Auxiliary forced air.

Auxiliary heat.

All of the above.

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

Suction line to be warmer than normal.

Suction line to be colder than normal.

Discharge line to be warmer than normal.

Discharge line to be colder than normal.

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

A monthly basis.

A quarterly basis.

A semiannual basis.

An annual basis.

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

Mullion heater is defective.

Defrost time clock is defective.

Defrost termination switch is defective.

Evaporator fan motor is defective.

34. You can reduce the danger involved in attaching high-pressure gauges on a manifold by shutting off the...

Refrigerant and allowing it to cool.

High side and allowing the pressures to equalize.

Valves and allowing the pressures to equalize.

Unit and allowing the pressures to equalize.

"Shutting off the unit and allowing the pressures to equalize" was marked correct on the official test.

Explanation

"Shutting off the unit and allowing the pressures to equalize" was marked correct on the official test.

35. The three components that operate in the cooling mode are the...

Compressor, the evaporator, and the outdoor fan.

Indoor fan, the compressor, and the outdoor fan.

Compressor, the indoor fan, and the defrost cycle.

Outdoor fan, the indoor fan, and the auxiliary heat.

36. A start capacitor on an electric motor is constructed as a...

Wet type.

Dry type.

Round type.

Square type.

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

95°F

105°F

115°F

125°F

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

Power supply is energized and the voltage is correct.

Connections are mechanically and electrically sound.

Contacts on all relays are clean and free to move.

Wires are all electrically insulated and tight.

39. What type of electrical problems will a hermetic compressor have?

Open circuit.

Short circuit.

Grounded circuit.

All of the above.

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

A defective start capacitor.

A burned motor.

A blown fuse.

A closed circuit.

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

Incorrect overload switch.

Open disconnect switch.

Incorrect power supply.

Open fuse or breaker.

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

One-eighth to one-fourth of the sight glass.

One-fourth to three-fourths of the sight glass.

One-fourth to one-half of the sight glass.

Three-fourths to one-half of the sight glass.

43. The temperature range of a refrigeration system depends upon the...

Product being refrigerated.

Condensing temperature.

Size of the compressor.

Ambient temperature.

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

8 to 12°F

10 to 14°F

12 to 16°F

16 to 22°F

45. A run capacitor on an electric motor is constructed as a...

Metal can.

Paper can.

Plastic can.

Bakelite iron can.

46. Which thermostat terminal passes power to the indoor fan?

R

G

W

Y

47. 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...

Compressor pressure.

Condenser pressure.

Air temperature in the box.

Air temperature at the condenser.

48. 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?

R, G, and W.

R, G, and Y.

V, B, and W.

V, B, and Y.

49. 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...

Capacitor is open.

Run windings are open.

Start windings are open.

Internal overload protector is open.

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

Has an open winding.

Has a grounded winding.

Centrifugal switch is open.

Centrifugal switch is closed.

51. Which is an indication that the defrost system is not operating properly?

Defrost is terminated by the time clock.

The unit operates with excessive head pressure.

The unit operates with excessive suction pressure.

Manually initiated defrost is terminated by the temperature sensing device.

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

Low suction pressure and high discharge pressure.

High suction pressure and low discharge pressure.

Low suction pressure and low discharge pressure.

High suction pressure and high discharge pressure.

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

Pressure test.

Water flow test.

Eddy-current check.

Megger current check.

Eddy-current check was marked as correct on official test.

Explanation

Eddy-current check was marked as correct on official test.

54. If the condenser in a refrigeration system cannot remove the heat from the refrigerant, the...

Suction pressure will decrease.

Discharge pressure will increase.

Liquid-line temperature will decrease.

Suction line will frost back to the compressor.

55. 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...

The high-side gauge readings.

The low-side gauge readings.

Ultralow pressure gauge readings.

All of the above.

56. When the temperature of a refrigerated space goes down, the compressor will have...

Less capacity because the suction gas gets thinner.

More capacity because the suction gas gets thinner.

Less capacity because the suction gas gets more dense.

More capacity because the suction gas gets more dense.

57. What is the normal temperature difference between the inlet and outlet water on a wastewater water-cooled condenser?

25°F

20°F

15°F

10°F

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

None, these systems are mandatory.

The system can increase the conductivity of the water.

The system can decrease the conductivity of the water.

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

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

The high-side gauge readings.

The low-side gauge readings.

Ultralow pressure gauge readings.

All of the above.

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

Superheat method.

Supercooling method.

Subcooling method.

Condensing method.

61. The box temperatures for high-temperature refrigeration systems start at...

30°F

45°F

50°F

65°F

62. 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...

Equalize to the system.

Stay the same.

Go down.

Go up.

63. What is the normal maximum reduction of temperature in cooling tower water if the ambient wet-bulb temperature is 85°F

72°F

75°F

78°F

81°F

64. A compressor that is not pumping at full capacity will have...

High suction and low head pressure.

High suction and high head pressure.

Low suction and low head pressure.

Low suction and high head pressure.