What is considered a good vacuum level for a deep vacuum?
A) 28 in Hg vacuum B) 100 microns C) 1,000 microns D) 500 microns
[Ques. 2] A transformer uses this electrical principle to increase or reduce voltage with no moving parts or contacts.
A) Resistance B) Electromotive force
C) Capacitance D) Induction
[Ques. 3] The electrical power supplied to houses is usually:
A) 240 V, single-phase power. B) 440 V, single-phase power.
C) 208 V, three-phase power. D) 230 V, three-phase power.
[Ques. 4] The vacuum level on a system being evacuated pulls down to 2,000 microns, but goes no lower even as the vacuum pump continues to run. This indicates:
A) That the system is charged with the wrong type of refrigerant.
B) The presence of water in the system.
C) That the vacuum is complete.
D) That the refrigeration oil is incompatible with the refrigerant in the system.
[Ques. 5] Once acid is created within the refrigeration system:
A) It can cause a burnout when the refrigerant is exposed to the compressor motor.
B) It becomes impossible to remove brazing oxides and metal particles from the system, even if a filter drier is used.
C) Dry nitrogen must be used to reverse the increase in system high-side pressure caused by the acid.
D) Only a multiple evacuation procedure can be used to evacuate the refrigeration system.
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