Improving Fan System Performance

Quiz Question

1. There are two primary types of fans:
a. Centrifugal
b. Axial
2. _______________ is a complex process that starts with a basic knowledge of system operating requirements and conditions such as airflow rates, temperatures, pressures, airstream properties, and system layout.
Fan selection
Vibration energy
3. Fan rotational speed is typically measured in ______________________.
Revolutions per minute (rpm)
4. Airstream temperature has no important impact on fan-speed limits because of the effect of heat on the mechanical strength of most materials.
5. ___________________ and particulate content are important considerations in selecting fan type.
6. ___________________ is typically defined by a plot of developed pressure and power required over a range of fan-generated airflow.
Fan performance
7. Fan efficiency is the ratio of the power imparted to the airstream to the power delivered by the motor.
8. What does BEP stand for?
Best Efficiency Point
Best Efficiency Plant
Best Efficiency Plot
None of the above
9. What does HVAC stand for?
Heating, Ventilation and Air Conditioning
Heating, Variety and Air Conditioning
Heavy, Ventilation and Air Conditioning
None of the above
10. The effects of heating and cooling coils on fan system performance depend largely on where in the system the heat exchangers are located, the extent of the temperature change, and how the heat exchangers are constructed.
11. There are some principal opportunities in the life cycle of a system that can be used to improve fan system performance. They are:
During initial system design and fan selection
During troubleshooting to solve a system problem
During a system capacity modification
All of the above
12. _____________________ refers to a wide range of causes and problems, including inadequate delivery to a system branch, surging operation, and high airflow noise.
Poor airflow control
High operations control
13. Axial fans generate airflow by accelerating the airstream radially and converting the kinetic energy into pressure.
14. ___________________ are those types of fans that are characterized by blades that tilt away from the direction of rotation.
Backward-Inclined Fans
Radial tip
15. What does NEMA stand for?
National Electrical Manufacturers Association
National Electrical Manufacturers Agency
National Engineering Manufacturers Association
None of the above
16. Tubeaxial fans are frequently used in exhaust applications because they create sufficient pressure to overcome duct losses and are relatively space efficient.
17. Common maintenance tasks on fan systems include:
Periodic inspection of all system components
Bearing lubrication and replacement
Belt tightening and replacement
Motor repair or replacement
Fan cleaning
All of the above
18. What does EPA stand for?
Environmental Protection Agency
Electrical Protection Agency
Environmental Policy Association
None of the above
19. The disadvantages of controllable-pitch blades include higher initial cost, exposure of the pitch angle linkage to fouling, and the potential efficiency and power factor effects that accompany operating a motor below one-half of its rated capacity.
20. ___________________ is a common characteristic of most duct systems.
Frequency drive