What causes a fan to surge?
As long as the outlet pressure of the blower is greater than the downstream pressure, the blower operates smoothly and efficiently. If the blower is slowed down enough or the downstream pressure rises suddenly beyond the capacity of the blower surge will occur.
How do you assess the performance of fans explain?
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. Static pressure Static pressure is the potential energy put into the system by the fan.
What happens if you put two fans in series?
In general, combining axial fans in series does not increase the airflow but increases the air pressure. When an increased air volume or pressure becomes necessary for an application, multiple fans can be used instead of replacing a single fan with a larger capacity fan.
What are the various factors which can affect fan performance?
Many factors influence the efficiency of a fan. These include motor efficiency, blade speed, housing design, clearance between the fan blades and fan housing, and blade shape. However, even the most efficient fan will not perform satisfactorily if it is not kept clean and properly serviced.
How does a fan increase pressure?
For a fan, it is based on the average air velocity at the fan outlet. As the velocity of the airflow increases, the velocity pressure increases. The total pressure developed by a fan is the sum of its static pressure and its velocity pressure. The acoustic energy emitted by a sound source.
Do fans increase pressure?
A fan increases the static pressure on it’s outlet and can also decrease the static pressure on the inlet slightly. Even though very slight in comparrison, a fan is technically a compressor. The static pressure rise is usually in the order of inches of water.
Can you put 2 inline fans together?
The maximum unrestricted flow will not be increased by mounting two fans inline with each other. If you put two of the same fans on the same side of a 2′ tube, the airflow would be the same as if there was only one.
Does putting two fans together?
Yes and no. Putting two fans together does not increase the maximum airflow of the fans. So if you have a fan that pushes 50cfm in a theoretical, no resistance situation, putting two of them together will still only push 50cfm. What stacking can do though is help overcome resistance to the fan.
Why is my CPU fan surging so fast?
Recently the CPU fan started surging to a high speed. After start-up, it can take up to a couple of hours for this surging to take place. 1. Ran Dell’s hardware diagnostics with no problems shown. 2. Opened the computer and checked for dust problems.
What are the common causes of a fan failure?
Fan failures: five typical problems and what causes them 1. Fan is too noisy. When an impeller hits the inlet or housing, it’s likely not centred; the inlet or housing is… 2. Fan is too quiet. When the fan is not operating at all, it’s likely straightforward mechanical and/or electrical… 3. Fan …
What should I do if I have a fan failure?
If the fan foundation is inadequate, are isolators properly sized and levelled; shims properly installed; anchor bolts properly sized, intact and installed on all anchor points; and is ducting twisting or rubbing? Check bearings: are they upgraded for a higher load capacity?
What happens when a fan hits an inlet?
1. Fan is too noisy. When an impeller hits the inlet or housing, it’s likely not centred; the inlet or housing is damaged; the impeller is crooked or damaged; there’s a loose shaft or loose bearing; a shaft is bent; or there’s a misaligned shaft and bearing.
Recently the CPU fan started surging to a high speed. After start-up, it can take up to a couple of hours for this surging to take place. 1. Ran Dell’s hardware diagnostics with no problems shown. 2. Opened the computer and checked for dust problems.
Which is the operating point of a surge fan?
 There must be a section of ductwork with relatively high velocities.  The operating point of the system is to the left of the peak pressure (at lower flow rates). In this region the fan curve has a positive slope, such that increasing the flow also increases the fan static pressure. In concept, a system in surge is like an oscillator.
What happens when the fan angle is too severe?
This change of direction (and relative velocities) allows the fan to generate pressure. If the attack angle becomes too severe, air will no longer follow the blade surface uniformly. The amount of deflection and the pressure being generated stops increasing and normally will fall off. This is called the stall point.
Why is my Ceiling Fan not producing enough air?
If the fan is running very sluggishly or isn’t producing enough air at the high-speed setting, it could be a problem with the intake or exhaust. You’ll have to check the intake of debris and make sure that the fan is placed high and close to the roof.