The most commonly used fan characteristic is the relationship between pressure rise and volume flow rate for a constant impeller speed (RPM). The air movement has a pressure associated with it, which is termed as static pressure (SP) and the velocity pressure (VP). The static pressure (SP) is the useful working pressure available for overcoming …
Fan drives can be reduced to two basic types: indirect drives (belt drives) and direct drives. Both types have strengths and weaknesses that should be considered carefully during selection. For a summary of the differences between direct and indirect drives, see Table C in the Appendix. Indirect (Belt) Drives Indirect drives, or belt drives, are …
Fans are typically driven by alternating current (AC) motors. In industrial fan applications, the most common motor type is the squirrel-cage induction motor. This motor type is commonly used because of its characteristic durability, low cost, reliability, and low maintenance. These motors usually have 2 or 4 poles, which, on a 60- hertz system, translate …
A typical fan system consists of a fan, an electric motor, a drive system, ducts or piping, flow control devices, and air conditioning equipment (filters, cooling coils, heat exchangers, etc.). To effectively improve the performance of fan systems, designers and operators must understand how other system components function as well. The “systems approach” requires knowing …
This section describes the most important energy efficiency opportunities for fans and blowers. Choose the right fan Important considerations when selecting a fan are (US DOE, 1989): Noise Rotational speed Air stream characteristics Temperature range Variations in operating conditions Space constraints and system layout Purchase costs, operating costs (determined by efficiency and maintenance), and operating …
Volute casing are classified on the basis of Cross-section of Volute passage and splitting of outlet passage for blower. PARALLEL SIDE WALLS In this type of volute casing the sides of the casing are parallel as shown in figure: 1.1. The width of the casing is nearly kept equal to the width of the impeller. …
The fans are tested for field performance by measurement of flow, head, temperature on the fan side and electrical motor kW input on the motor side. Air flow measurement Static pressure Static pressure is the potential energy put into the system by the fan. It is given up to friction in the ducts and at …
Imagine a fan selected with great care to provide exactly the performance required in the specifications. Once installed, the air balancer reports that air performance is considerably lower than required. What went wrong? The answer is probably system effect. The system effect is the change in system performance that results from the interaction of system …