Quiz 6 - Commercial Wiring - Unit 9 Flashcards
Keeping a refrigerator door open will help cool the surrounding area.
True
False
Mechanical refrigeration relies primarily on the process of evaporation.
True
False
Cooling the skin is created by,
Body heat converting energy from gasoline
Body heat converting energy to alcohol
Body heat being transferred away from the body
All of the above
The refrigerant cycle requires the following components
Expansion valve, compressor, evaporator, condenser
Condensation, evaporation, heat transfer
Refrigerant preservation, evaporation valve, body heat
All of the above
Both A and B
The function of an evaporator is,
To add heat and condensation
To evaporate the heat
To remove heat from the interior of a building or space
Both B and C
The compressor serves as a pump to push the expanded refrigerant gas to the evaporator.
True
False
The function of the condenser is to discharge the heat extracted by the evaporator and the heat of the compression.
True
False
Figure 9-8 is showing,
A hermetic compressor which consists of a motor-driven pump completely sealed in a liquid-tight steel casing
A hermetic compressor which consists of a motor-compressor completely sealed in a gas-tight steel casing
A hermetic compressor which consists of a motor-condenser completely sealed in a gas-tight weatherproof casing
All of the above
Both B and C
CFC’s aren’t harmful to the atmosphere.
True
False
Circuit breakers are permitted if a nameplate specifies fuses because they’re both overcurrent devices.
True
False
The rated load current,
Is governed under 28-010
Is at minimum equal to 64.1% of the MCC (maximum continuous current)
Is equal to 64.1% of the RLA
Both A and C
A common disconnecting means for a starting winding is
A contact-relay assembly
A horsepower rated fusible disconnect
A centrifugal switch
All of the above
A locked rotor current,
Is equal to the full load current
Is approximately six times the FLC
Can be found in Tables 44 or 45
All of the above
Both B and C
The minimum circuit ampacity,
Can be obtained by multiplying the RLA by six
Is the rated load current multiplied by a hundred and twenty five percent
Is 125% of the MCA
All of the above
Both A and B
According to 28-708(1), the maximum overcurrent protective device (MOP),
Is the LRC times 1.5
Must not be less than fifty percent of the LRC
Must not be greater than fifty percent of the LRC
All of the above
Both A and C
According to 2-024, electrical equipment being approved depends on the rating of equipment.
True
False
According to 28-710, maximum overload protection must be greater than 140% of the RLC.
True
False
Disconnect switches are
Horsepower rated
Rated for low voltage
Rated for ambient temperatures above 30 degrees Celsius
All of the above
According to 28-714(1a), disconnects for hermetic motor compressors must not be rated less than 115% of the RLA.
True
False
A refrigeration disconnecting means shall be capable of safely disconnecting the full locked rotor current according to which rule?
28-604(5)
28-714(1b)
28-714(2b)
All of the above
The larger value of either the FLA or the LRA will determine the size of disconnect switch installed.
True
False
According to 28-604(5,6), a disconnecting means must be accessible, within sight, and not more than 3 meters from the air conditioning or refrigeration equipment.
True
False
Rule 28-708(1) allows a fifty percent size limit on overcurrent protection to be increased to sixty five percent is the equipment cannot start.
True
False
Rule 28-302 allows for an integral thermal protector to interrupt current flow to a motor compressor.
True
False
The electricians job is to make sure that equipment is fed by the proper size conductors, with the proper size and type of branch-circuit overcurrent protection, and the proper horsepower rated disconnecting means.
True
False
