Air Density (Temperature and Altitude) Air density is a variable of elevation and temperature, and both these variables affect fan air performance. Air density will affect the total pressure that a fan can generate and the horsepower required to move the air. Most fan performance is published at a density based on air at 70°F …
Troubleshooting is the effort to identify and resolve differences between what was expected and what actually happened. The following four categories narrow the focus of attention and speeds up the evaluation process. Aerodynamic Performance – This applies to any of the five rating parameters of flow, pressure, speed, power and density and how they compare …
Noise is generally considered low quality, unwanted sound. The primary selection criterion for a fan is based not on its acoustical characteristics but on its ability to move the required amount of air against the required pressure. In addition, the fan must do so at a reasonable initial cost (it also may be required to …
Fans are constructed from many different materials, and like everything else, there are pros and cons to any option. Heavy solid-blade fans may experience extended starting times due to the high inertia load that the motor must accelerate to speed. It is not unusual to have electric motor overloads trip from extended starting times when …
FAN MANTENANCE To obtain maximum service life of your fans, it is recommended the following maintenance be implemented and recorded in a plant log book Ensure air intake space is unobstructed to avoid overheating the motors. On a weekly basis use an air hose to ensure all airways are clear and free of dust if …
Most fans are sized to handle the largest expected peak design condition. Because normal operating conditions are often well below these design conditions, air-moving equipment is often oversized, operating below its most efficient point and creating several types of problems. Among these problems are high energy costs, high system pressures and flow noise, and, in …
Roof Exhaust Fans Figures below illustrate how roof exhausters are tested; AMCA refers to Fig#1 setup as “Type A: Free inlet, free outlet”. Fig # 2&3 illustrate roof exhaust fan installations having system effects. Fig # 3 illustrates the worst case, because the damper is located in a turbulent airstream. To improve on installations where …
Fan laws relate the performance characteristics of any geometrically similar series of fans. CFM, RPM, SP and HP are all related to each other in a known manner and when one changes, all others change. The CFM variable is the most commonly changed measurement in an air moving system therefore the following example of Fan …