Mohawk AC & Refrigeration Exam Prep 2026/2027 |
Questions & Correct Answers | Graded A+
1. Describe the significance of alternations in defining an electrical cycle.
An electrical cycle includes three alternations, which is necessary for
full power.
An electrical cycle is characterized by four alternations, which is
standard in high voltage systems.
An electrical cycle consists of two alternations, which represent the
complete waveform of alternating current.
An electrical cycle is defined by one alternation, indicating half of the
waveform.
2. What are the standard voltages available from a 4 wire 208 volt electrical
system?
110 volts, 220 volts
480 volts, 240 volts
240 volts, 120 volts
208 volts, 120 volts
3. What is the typical relationship between locked rotor current and run current
in an air conditioning system?
The locked rotor current fluctuates around the run current.
The locked rotor current is equal to the run current.
The locked rotor current is usually lower than the run current.
The locked rotor current is usually much higher than the run current.
,4. What is the primary method used to decrease the superheat setting of a
Thermal Expansion Valve (TEV)?
Raising the evaporator temperature
Increasing the refrigerant flow
Adjusting the valve spring tension
Lowering the sensing bulb temperature
5. What does the abbreviation TD stand for in the context of an evaporator in a
refrigeration system?
Temperature Difference
Thermal Dynamics
Total Density
Turbine Drive
6. What is the purpose of refrigeration service valves in a refrigeration system?
To regulate the temperature of the refrigerant.
To allow for the servicing and maintenance of the refrigeration
system.
To filter impurities from the refrigerant.
To increase the pressure of the refrigerant.
7. Which parameter is essential for calculating the compressor displacement in
an air conditioning system?
Diameter of pistons
Refrigerant type
, Length of pistons
Compressor speed
8. What is the primary role of the condenser in an air conditioning system?
To release heat from the refrigerant.
To expand the refrigerant.
To compress the refrigerant.
To absorb heat from the environment.
9. In a refrigeration system experiencing frequent compressor failures, what
might be a potential solution involving the suction accumulator?
Increase the refrigerant charge to improve cooling efficiency.
Install a suction accumulator to prevent liquid refrigerant from
reaching the compressor.
Reduce the size of the evaporator coil to decrease refrigerant flow.
Replace the compressor with a larger model to handle the load.
10. What is the voltage rating of the blown start capacitor mentioned in the
provided question?
140 volts
440 volts
250 volts
330 volts
11. What is the typical amount of air required per ton by an air cooled
condenser?
, 600 CFM
200 CFM
800 CFM
400 CFM
12. Describe the significance of evaporator TD in the performance of a
refrigeration system.
Evaporator TD represents the thermal dynamics of the refrigerant
flow.
Evaporator TD indicates the temperature difference between the
refrigerant and the air or liquid being cooled, which affects the
system's efficiency.
Evaporator TD measures the total density of the refrigerant in the
evaporator.
Evaporator TD is used to calculate the pressure drop across the
evaporator coils.
13. What is the primary function of the starting winding in a single phase motor?
To regulate the motor's speed.
To reduce electrical noise during operation.
To maintain continuous operation of the motor.
To provide the initial torque needed to start the motor.
14. If the temperature of a gas is increased while keeping its volume constant,
what will happen to its pressure according to gas laws?
The pressure will remain the same.
The pressure will increase.
Questions & Correct Answers | Graded A+
1. Describe the significance of alternations in defining an electrical cycle.
An electrical cycle includes three alternations, which is necessary for
full power.
An electrical cycle is characterized by four alternations, which is
standard in high voltage systems.
An electrical cycle consists of two alternations, which represent the
complete waveform of alternating current.
An electrical cycle is defined by one alternation, indicating half of the
waveform.
2. What are the standard voltages available from a 4 wire 208 volt electrical
system?
110 volts, 220 volts
480 volts, 240 volts
240 volts, 120 volts
208 volts, 120 volts
3. What is the typical relationship between locked rotor current and run current
in an air conditioning system?
The locked rotor current fluctuates around the run current.
The locked rotor current is equal to the run current.
The locked rotor current is usually lower than the run current.
The locked rotor current is usually much higher than the run current.
,4. What is the primary method used to decrease the superheat setting of a
Thermal Expansion Valve (TEV)?
Raising the evaporator temperature
Increasing the refrigerant flow
Adjusting the valve spring tension
Lowering the sensing bulb temperature
5. What does the abbreviation TD stand for in the context of an evaporator in a
refrigeration system?
Temperature Difference
Thermal Dynamics
Total Density
Turbine Drive
6. What is the purpose of refrigeration service valves in a refrigeration system?
To regulate the temperature of the refrigerant.
To allow for the servicing and maintenance of the refrigeration
system.
To filter impurities from the refrigerant.
To increase the pressure of the refrigerant.
7. Which parameter is essential for calculating the compressor displacement in
an air conditioning system?
Diameter of pistons
Refrigerant type
, Length of pistons
Compressor speed
8. What is the primary role of the condenser in an air conditioning system?
To release heat from the refrigerant.
To expand the refrigerant.
To compress the refrigerant.
To absorb heat from the environment.
9. In a refrigeration system experiencing frequent compressor failures, what
might be a potential solution involving the suction accumulator?
Increase the refrigerant charge to improve cooling efficiency.
Install a suction accumulator to prevent liquid refrigerant from
reaching the compressor.
Reduce the size of the evaporator coil to decrease refrigerant flow.
Replace the compressor with a larger model to handle the load.
10. What is the voltage rating of the blown start capacitor mentioned in the
provided question?
140 volts
440 volts
250 volts
330 volts
11. What is the typical amount of air required per ton by an air cooled
condenser?
, 600 CFM
200 CFM
800 CFM
400 CFM
12. Describe the significance of evaporator TD in the performance of a
refrigeration system.
Evaporator TD represents the thermal dynamics of the refrigerant
flow.
Evaporator TD indicates the temperature difference between the
refrigerant and the air or liquid being cooled, which affects the
system's efficiency.
Evaporator TD measures the total density of the refrigerant in the
evaporator.
Evaporator TD is used to calculate the pressure drop across the
evaporator coils.
13. What is the primary function of the starting winding in a single phase motor?
To regulate the motor's speed.
To reduce electrical noise during operation.
To maintain continuous operation of the motor.
To provide the initial torque needed to start the motor.
14. If the temperature of a gas is increased while keeping its volume constant,
what will happen to its pressure according to gas laws?
The pressure will remain the same.
The pressure will increase.
