Fan not pulling full amps fan performance 80% of design fan sounded like it was hunting eg in stall initial diagnoses was uneven air on conditions due to transition pieces damper in front of fans disruption air flow on to blades. Q is flow volume, a is impeller area, d is impeller diameter. Although they can sometimes be used interchangeably with centrifugal fans, axial fans are commonly. Continued and ever shortening product design cycles demand a get it right the first time approach. Even though the performance curves for the vaneaxial fan and the centrifugal fan have completely different shapes, the curves are read in the same way. In a fan, the blades are normally rotating at constant velocity. With adjustable pitch fans or belt drive fans that display multiple curves, you can calibrate between the curves for blade angle or rpm settings that are not givensee example.
Figure 6 shows a fan curve of a fan with a significant dip in the stall region. Fan curves graphically depict fan performance data of cfm, rpm, sp, and bhp. For applications requiring a large air volume at a low static pressure, the bhp required at the fans operating rpm may not be sufficient to initially start. Development and testing of the characteristic curve fan model. Two to 10 inches water gauge is the expected pressure range for a single stage fan.
This action causes a new system performance curve sc2 where the required pressure is greater for any given air flow. Typical performance curves for a single impeller speed and diameter appear as. The new york blower company is committed to supporting and supplying necessary equipment to meet the critical demands of the supply chains essential to aid america in this time of need. The article has explained the fan curves basics, but drawing correct system curve is not a easy task and selecting the fans operating point depends largely on preparing correct system curve. Introduction to fan systems fans 3 fan performance curves 6 fan system components 9 section 2. Study on pq curves of cooling fans for thermal design of electronic equipment effects of opening position of obstructions near a fan january 2011 doi. Titus timeout podcast how to read a fan curves part 2 duration. At fan speed n 1, the fan will operate along the n 1 performance curve as shown in figure 5. The first thing to note about the fan curve graph is that it has 3 axes. The fan performance tables and curves in this catalog show the brake horsepower required to operate the fan once it is brought to speed. Technical how to read performance curves axair fans. Choose a fan that has its peak efficiency at or near your operating point. Fan affinity laws applies to all centrifugal loads flow proportional to the speed pressure proportional to the speed squared power proportional to the speed cubed speed % input power % 100 0 80 60 40 20 0 10 20 30 40 50 60 70 80 90 100. A fan operates along a performance given by the manufacturer for a particular fan speed.
For complete product specifications and submittal data isit us at. The fan curves predict the pressureflow rate performance of each fan. The vaneaxial fan figure 11 is a variation of the duct fan design which operates in the mediumtohigh pressure ranges. Rating tables and performance programs 41 selection and rating areas are defined by the manufacturers, usually only good selections are shown. The air is pressurized by the aerodynamic lift generated by the fan blades, much like a propeller and an airplane wing. Reducing or increasing the fans rotational speed respectively reduces or increases the height of the fans characteristic curve as exhibited on the example curves below. The affinity laws for centrifugal pumps and fans are used to express the influence on volume capacity, head pressure andor power consumption due to. In addition to being more useful for ventilation planning, this is. Performance curves housings on all fans are constructed out of 14 inch steel plate. Various axial and centrifugal fan performance curves will be illustrated throughout this article with no attempt made to rationalize any particular selection.
Page 14 performance data determination the fan performance section of this catalog contains a fan performance table and fan curve for each fan size. Knowledge of fan performance curves, and how they are obtained, allows for a more informed decision when selecting a fan. Factors which determine the performance of the fan include the number and shape of the blades. Theoretical model for predicting axial fansblowers performance characteristics 3 l l 2 l 2 m v w2 r 2 m v w1 r 1 m v w2 r 2 3 m av f q, q av f m3s and a 4 2 d 2 1m2 m, is a constant mass flow rate between entry and exit. The performance curve describes a blowers ability to deliver flow rate against backpressure from zero backpressure open flow to. Performance data intermittent volume parallel flow, low profile design external static pressure 0. And flanges are 38 inch steel for greater strength. Fan performance curves the performance curves for these fan types have been established in mounting position d according to amca 210, installed on the pressure side and suction side and represent the total pressure increase dp t as a function of the volume flow. Fan performance other than that anticipated when the fan was initially selected less flow, higher pressure, greater power consumption due to reduced fan efficiency. This flier provides a brief overview of the fans and blowers industrial air technology corp. An axial fan is a type of fan that causes gas to flow through it in an axial direction, parallel to the shaft about which the blades rotate.
For a more indepth look into the characteristics of different fan types, refer to fe2300 for axial fans and fe2400 for centrifugal fans. These curves show the relationship between the quantity of air a fan will deliver and the pressure generated. All charts are organized by fan size and nominal motor rpm. Development and testing of the characteristic curve fan model jeff stein, p. The system curve, the fan curve, and the operating point. Fan laws and system curves new york blower company. The fan performance chart shows performance curves for a series of fan speeds. The pressure is produced simply by the lift of the rotating blades as air moves over it.
Fan curve density effects fan curves are developed for air at normal conditions 14. Factors which determine the performance of the fan include the. Being able to read a fan curve will allow you to choose the best fan for your requirements, as long as the fan is properly tested and certified. Fan curves basics explained understanding fan performance curve. These curves are observed to have the following characteristics. The performance of the vaneaxial fan figure 12 shows the pressure curve to rise steeply from free. Member ashrae member ashrae jeff stein is a senior engineer and mark hydeman is a principal at taylor engineering, llc, alameda, calif. Curves are normally supplied for each specific fan on a given project. The performance data contained in this catalog was calculated from tests conducted in accordance with amca standard 210 laboratory methods of testing fans for rating. Fan curves one of the most valuable pieces of information supplied by fan manufacturers is the fan performance curve. The fan will now operate at b to provide the reduced air flow q2 against higher pressure p2. Characteristics and selection parameters of fans and.
Fan performance tables are at standard conditions 0. Blower application basics blower application basics. Fdc fan curves1 v001 performance data fdc with ecm fan performance curves unit size 10 static pressure, inches w. To access this material simply click on the link or to save right click and select save target as. When your system curve intersects the cfm vs sp curve this is indicative of that fans performance when applied to your actual system. Mcpherson 5 fan manufacturers usually publish characteristic curves in terms of fan static pressure rather than the fan total pressure.
Note that the affinity laws for pumps are not identical with fans fan affinity laws. These types are characterized by the path of the airflow through the fan. The fan supplier will then select a suitable sized motor to the fan. The fan is designed to produce a pressure difference, and hence force, to cause a flow through the fan.
Once you select your cfm, draw a line vertically up to intersect the cfm vs sp curves that run from lower right to upper left. Fans and blowers bureau of energy efficiency first method is to restrict the air flow by partially closing a damper in the system. Computer software is available to provide selections and performance curves. The dynamic pressure p d2 refers to the flange crosssectional area at the of the.
Performance improvement opportunity roadmap 1assessing fan system needs 17 2 fan types 19 3basic maintenance 25 4common fan systems problems 29 5indications of oversized fans 33 6system leaks 37. Within each chart, there are a series of solid black lines with corresponding dashed lines. Performance data fch with ecm fan performance curves static pressure, inches w. Higher flow rates through the inlet increase the attack angle, and.
The fan s actual operating point on this curve will depend on the system resistance. The solid black lines represent the fan curves for each fan and are broken down by partial wheel widths. The performance curve describes a blowers ability to deliver flow rate against backpressure from zero backpressure open flow to completely blocked flow sealed. The performance curves shown in this catalog represent each models typical maximum performance full speed at a constant input voltage. Fan curves manufacturer will provide a fan curve for each fan he or she produces. Locate some unit of pressure on the left hand sp scale 4 units and project a horizontal line to the point of intersection with the sp curve. I will write something next on how to draw a system curve. The second curve shows the relationship between the fans air volume flow rate and the brake horsepower.
Choose a fan that gives you the volumetric flow rate you need for your system pressure drop. Study on pq curves of cooling fans for thermal design of. All housings are rolled in our shop in farmington, new mexico, so quality will be topnotch. The fan ttotal eefficiency can be calculated by using the formula. The upfront use of system curves, fan curves and fan laws can help meet this goal.
Trane applications engineers discuss fan performance curves and fan laws, different fan types fan blade shape, housed vs. The fans actual operating point on this curve will depend on the system resistance. At fan speed n1, the fan will operate along the n1 performance curve as shown in figure 5. The following performance charts are for the selection of qeid mixed flow inline fans. Therefore, to change the angle of attack, the system to which the fan is attached must be changed. Rotron regenerative blowers performance curves regenerative. Mql units form eteg fan performance curves mql02 fan 0904 class i mql03 fan 0906 class i 16 envirotec mql modular airhandling units or et9e 45 mql06 fan 1209 class i mql04 fan 1007 class i envirotec 17 mql units form eteg. Engineers and designers who select and specify fans should have a good basic knowledge of fan curves and an understanding of how these are produced is vital for verifying the original fan selection, trouble shooting after the installation, and understanding future flexibility. How to read a fan performance curve g squared engineered.
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