1. Product Training Course
Part I: The Line of Fan Knowledge

2. The Role of Cooling Fans
a. Essential to systems that generate a significant amount of heat
b. Protect systems from overheating and malfunctioning
c. Come in different makers and models, and are engineered
specifically for the system in designs
Introduction

3. • 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

4. 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

5. 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…

6. Axial Fan Structure
Three Major Parts:
Rotor
Stator
Frame
Rotor -(incl. impeller, axial,
case, Magnet)
Stator- (incl. Bearing, SI steel,
Cover, PCB & fastener)
Frame

7. 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

8. Blower Structure
Three Major Parts:
Top Cover
Impeller
Bottom Cover
Top Cover
Impeller
Bottom Cover

9. Fan Performance Guide
How to measure the performance of fan?
• Air Flow
• Air Pressure
• Air Speed
• Air Noise
• Fan Blade
• Bearing Type

10. 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

11. 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

12. 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)

13. 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)

14. 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

15. 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.

16. Fans & Bearing
Three Bearings Analysis I
Type Advantage Weakness
Ball Bearing
1. suitable for lower speed
2. high reliability & durability
3. seal type, no oil
leakage problem
1. high cost
2. irregular rolling is larger while the
motor spinning at high speed and
easier to create vibration
3. big vibration and high noise
Sleeve Bearing
1. low cost
2. easy to produce
1. low life expectancy
2. face to face friction and easily to
lead abrasion
3. material is softer
Combined
Bearing
(one ball and one
sleeve)
1. work in quite complicated
conditions
2. less sensitive to a
unbalance of an impeller
3. lower vibration
1. high noise level
2. lower life expectancy
3. oil leakage problem

17. Fans & Bearing
Three Bearings Analysis II
Type Life Expectancy Environment Noise Level Mounting
Ball Bearing 60,000 hours
Higher heat,
no shocks
High Any
Sleeve Bearing 30,000 hours
Low heat, higher
shocks
Low Horizontally
Combined
Bearing
(one ball and
one sleeve)
40,000 hours
Low heat,
higher shocks
Medium Any

18. 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

19. 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 voltage
3, 5, 12, 24 and
48 VDC
Case is usually
made from
thermoplastic
medical
instruments,
telecom switches,
car
entertainment
systems

20. AC & DC Fans
AC & DC Current

21. 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

22. 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

23. AC Fan Assembly Chart

24. DC Fan Assembly Chart

25. 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

26. Contact Us
USA Office
275 Paseo Tesoro
Walnut, CA 91789
Tel: +1-909-598-6033
Fax: +1-909-598-6043
Email: sales.usa@cooltron.com
China Office
6F,Taojing Bldg., Mingbao Rd.,
Minzhi, Baoan District, Shenzhen, China
Tel: +86-755-8209-0805
Fax: +86-755-2904-3077
Hong Kong Office
Room 2005, 20/F, Centremark,
287-299 Queen's Road. Central,
Hong Kong