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

Contact Us

USA Office275 Paseo TesoroWalnut, CA 91789 Tel: +1-909-598-6033 Fax: +1-909-598-6043Email: sales.usa@cooltron.com

China Office6F,Taojing Bldg., Mingbao Rd., Minzhi, Baoan District, Shenzhen, ChinaTel: +86-755-8209-0805Fax: +86-755-2904-3077

Hong Kong OfficeRoom 2005, 20/F, Centremark,287-299 Queen's Road. Central, Hong Kong