product training fan knowledge
TRANSCRIPT
Product Training Course
Part I: The Line of Fan Knowledge
The Role of Cooling Fansa. Essential to systems that generate a significant amount of heatb. Protect systems from overheating and malfunctioning c. Come in different makers and models, and are engineered specifically for the system in designs
Introduction
• Types of Air Mover Products : Axial Fans vs. Blowers
• Structure of Cooling Fans and Blowers
• Fan Performance Guide & Fan Characteristics
• Differences in AC & DC Fan
• How to Select an Ideal Fan
Fan Knowledge Topic Agenda
What are axial fans and blowers?
4.Product Performance
5.Applied Work Systems
6.Flow Direction
Types of Air Mover Products
1.Size
2.Shape
3.Product Features
Axial Fan
* Axial Fans ( also called “box fans”)- Large volume airflows- Low-pressure - Low system impedance conditions- Low noise level
* Flow Direction:
- bow air across their axis in a linear
direction
* Markets – CPU, IT, home, office,
telecom, medical, industrial equipments,
and etc…
Axial Fan Structure
Three Major Parts:
Rotor
Stator
Frame
Rotor -(incl. impeller, axial,case, Magnet)
Stator- (incl. Bearing, SI steel, Cover, PCB & fastener)
Frame
Blower
* Blowers
- More concentrated airflows
- High system impedance conditions
- High level of noise
- Option for single or dual inlets
*Flow Direction:
- The flow go in from the shaft
direction and out from the radial
direction
* Markets – office automation equipment,
network servers, industrial and telecom
systems, and portable consumer product
Blower Structure
Three Major Parts:
Top Cover
Impeller
Bottom Cover
Top Cover
Impeller
Bottom Cover
Fan Performance Guide
How to measure the performance of fan?
• Air Flow• Air Pressure
• Air Speed• Air Noise • Fan Blade• Bearing Type
Fan Characteristic – Fan Air Flow
• The total cubit of flow moved in certain time
• CFM (Cubic Feet Per Minute) indicates the volume of air that a fan will move in one minute at zero static pressure.
• Unit: CFM : ft^3/min, CMM : m^3/min; 1 CMM = 35.315 CFM
Fan Air Flow (CFM)
• Purpose: to provide the required flow for heat dissipation
Fan Characteristics – Static Pressure
• Purpose : To resist the resistance created by system
• The amount of resistance in a circulation that a fan must surmount to ensure proper air movement
• As the pressure differential rises, the airflow drops
Static Pressure (mm-H2O)
• Unit : mmH2O, InH2O; 1InH2O = 25.4mmH2O
Fan Characteristic – Fan Air Speed
• Purpose: to provide the required speed to the required amount of cooling
• Fan blade rounds per minute
• The more airflow generated, the faster fan blade rotates
• Unit: RPM (Revolutions Per Minute)
Fan Air Speed (RPM)
Fan Characteristic – Fan Noise
• Purpose: to know if the fan noise level would affect the system operation in work environment
• Noise is measured in accordance with ISO7779 standards in Anechoic Chamber with less than 18.6 dBA background noise
Fan Noise (dBA)
• The greater the change in air pressure, the louder the resulting noise will be.
• The noise created by airflow and normal friction from mechanical structure.
• Unit: dBA (A-weighted decibels)
Fan Characteristic – Fan Blade
• The direct influence of performance of the airflow and air pressure
• the more fan blades, the higher air pressure• the more fan blades, the higher airflow • the more fan blades, the harder to maintain the plastic mold
Blade Shape and Numbers of Blades
Bearing Types
Bearing Types – ball, sleeve, and one ball one sleeve
In order for a cooling fan to work efficiently, it relies on bearings. These bearings reduce friction and allow a fan to operate at high speeds. Three standard fan bearing types are ball, sleeve, and one ball one sleeve. Which type of bearing a fan utilizes depends on its function as well as the speed at which it moves.
Fans & Bearing
Three Bearings Analysis IType Advantage Weakness
Ball Bearing
1. suitable for lower speed2. high reliability & durability3. seal type, no oil leakage problem
1. high cost2. irregular rolling is larger while the motor spinning at high speed and easier to create vibration3. big vibration and high noise
Sleeve Bearing 1. low cost2. easy to produce
1. low life expectancy2. face to face friction and easily to lead abrasion3. material is softer
Combined Bearing
(one ball and one sleeve)
1. work in quite complicated
conditions 2. less sensitive to a unbalance of an impeller3. lower vibration
1. high noise level2. lower life expectancy3. oil leakage problem
Fans & Bearing
Three Bearings Analysis II
TypeLife
ExpectancyEnvironment Noise Level Mounting
Ball Bearing 60,000 hours Higher heat,no shocks
High Any
Sleeve Bearing 30,000 hoursLow heat, higher shocks
Low Horizontally
Combined Bearing
(one ball and one sleeve)
40,000 hours Low heat,higher shocks
Medium Any
AC & DC Fans
a. The Type of AC and DC fans
b. Uses of AC and DC fans
c. Installing AC and DC fans
d. AC and DC fans Selection
Differences in AC and DC Fan
AC & DC Fans
AC VS DC Fans
Type of Electricity
Voltage Options
Construction Applications
AC FAN -alternating current (AC) charges that change direction quickly. -provide a constant flow
higher voltage 110, 115, 120, 220, 230, 240 VAC
Case is usually made from die cast aluminum
in a wide variety of higher power applications
DC FAN -direct current (DC) electrical flows that only move in one direction -provides a variable, uneven flow
Lower voltage3, 5, 12, 24 and 48 VDC
Case is usually made from thermoplastic
medical instruments, telecom switches, car entertainment systems
AC & DC Fans
AC & DC Current
Connector Types – AC & DC Fan
AC Terminal Connectors
• Wire Cord• Power Plug Cord
AC Wire Connectors(Leads)
• two black colored wires• soldering required each time when the fan needs to be replaced
AC Fans
DC Fans
DC Wire Connectors
• two or more wires• the first wire – red color -> positive voltage• the second wire – black color negative voltage• additional wires –> special fan functions (thermistor, PWM)• bounded together with a molex or pin connector at the end
Connector Types – AC & DC Fan
DC Fan with lead wire
Offer an alternative for customize design
AC Fan with lead wire AC Fan with terminal lead
two black wires
Black -> negative
Red -> positive
power plug cord
AC Fan Assembly Chart
DC Fan Assembly Chart
How To Choose an Ideal Fan
• Current and Voltage• Case Dimensions• Decide Connector Type• Measure the heat • Decide the permissive temperature in the unit• Calculate the required air volume• Estimate the system impedance• Select the data sheet by fan performance curve
Guideline to choose a fan best fits your application
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