3 PIN FAN VS 4 PIN FAN

内容目录

Function of 3 Pin Fan & 4 Pin Fan

Most cooling fans will connect to a PC with a standard connector of some sort. Modern systems will typically use 3-pin or 4-pin dedicated fan headers, though standard MOLEX 4-pin peripheral connectors are also used. From left to right: A 3-pin connector, a 4-pin connector and a MOLEX connector.

3 Pin Fan

The 3 pin fan connector has three indicators (as per the number of wires): The first wire is for power (4 to 12 volts), 2nd is for ground and 3rd wire is for a tachnometric signal (speed sensor) this sensor monitors the fan speed and performance.

A tachnometric signal adjusts the level of power applied to the motor by transmitting the speed of rotation of the fan impeller at a nominal voltage between 5 to 12 volts. In this way, the fan speed is typically controlled by increasing or decreasing the voltage across the power cable.

Pinout 

1 Ground

2 +5V ~12V

3 Tachometer

4 Pin Fan

4 pin fan headers are commonly found in modern motherboards. The 4 pin fan connector is slightly different from the 3 pin connector also works the same but the additional 4th wire is PWM (Pulse Width Modulation) used for controlling the power supply of the load and rotation speed of the fan impeller.

The duty cycle of the PWM signal controls the speed of the fan motor. The motor will be supplied with 12 V (for example )throughout, however, the duty cycle of the PWM signal decides how long the fan should be running or not. A duty cycle of 40% keeps the fan on for 40% of the total time period of the PWM signal, and the other 60% of the time it will remain off. The speed variation of cooling fans is within 30-100% of the rated speed, with the PWM technique and the minimum speed achieved by PWM fans being much lower than DC fans. The chassis and CPU temperature are the two factors that influence the speed of the cooling fans. The new technology advancements have brought firmware and software controlled PWM fans, where the speed is controlled according to the CPU or case temperature. The PWM fans are commonly seen as CPU coolers with higher power consumption.

PWM CONTROL SIGNAL 

●THE FREQUENCY FOR CONTROL SIGNAL OF THE FAN SHALL BE ABLE TO ACCEPT 16K~32 KHZ.
●  THE PREFERRED OPERATING POINT FOR THE FAN IS 25K HZ.
●  AT 100% DUTY CYCLE,THE ROTOR WILL SPIN AT MAXIMUM SPEED.
●  AT 0% DUTY CYCLE,THE ROTOR WILL STOP.
●  WHEN CONTROL SIGNAL LEAD DISCINNECTED,THE FAN WILL MAXIMUM SPEED.
●  AT 25K 3%~5% DUTY CYCLE,THE FAN WILL BE ABLE TO START FROM A DEAD STOP.
●  THE FAN SPEED CONTROL IS CLOSED-LOOP.

PWM CONTROL LEAD WIRE INPUT IMPEDANCE

1.  THE FAN SPEED  WILL DEFAULT TO MAXIMUM WHEN THE SPEED CONTROL INPUT IS LEFT UNCON
2.  ABSOLUTELY NO INTERNAL PULL-UP.NECTED.

FG and RD Function Introduction

FG (Tach output type) Connection Diagram

      Fan with FG function will creat a square wave output.You can know fan speed by sensing the output wave Frequency. Most dc fan have four pole.So when fan run for one round,there will be two high level pulse. About other Multipole brushless fan,high level pulse will be different.

      But please notice if you want to sense it’s output wave,there is a external circuit. Please check the circuit Diagram below. There is no pull-up and VCC value limit.But please notice the Max Iin have to be small than 20mA.

RD (Alarm output) connection Diagram

      Some fan have RD extra function.There is a alarm signal output when fan stop work.Please notice there are Two kinds of signal output. Different customer will need different alarm type.Please check the diagram below.RD alarm input voltage3.3V. RD output current20MA

Lisa

14 years in Foreign Trade

Share:

More Posts

high performance fan 12038

MG12038: Top 12V DC Axial Fan for Air Filtration

In the air filtration industry, high-performance cooling fans are vital for efficiency and reliability. Mega Tech’s MG12038 12V DC axial fan redefines cooling with over 290m³/h airflow, low 48dB noise, and rapid RPM changes under 1 second. Designed to replace the noisy and costly EBM-PAPST 4312 N/2H3P, the MG12038 offers superior performance and 20% cost savings. With PWM control, durable ball bearings, and a low-inertia design, it meets demanding operational cycles, ensuring seamless integration into air filtration systems. Our client, a leader in air filtration, reported quieter operation, faster RPM adjustments, and significant savings after adopting the MG12038. Discover how Mega Tech’s innovative cooling solutions can enhance your systems. Contact us to explore the MG12038 today! #CoolingFan #AirFiltration

active cooling system

MEGA’s IP68 Cooling Fans for Gobo and LED Projector Thermal Management

Are your Gobo or LED projectors overheating?MEGA’s IP68 axial fans (120x25mm, 92x38mm, 150x38mm) provide robust cooling for indoor and outdoor use.Our customizable, cost-effective fans enhance projector performance and durability.Contact MEGA today to optimize your projector designs with tailored cooling solutions!

6010 frameless fan for charger-1

Mega EV Charger Cooling Fans

Discover Mega Tech’s advanced cooling fans for EV chargers. Our 6025, 5020, 8025, and 6010 bracket fans provide reliable and
efficient cooling solutions for 2-wheeler and 3-wheeler EV charging stations.

Send Us A Message

Ask For A Quick Quote

We will contact you within 1 working day.

DOWNLOADCATALOGUE

Note: Your email information will be kept strictly confidential.

DOWNLOADCATALOGUE

Note: Your email information will be kept strictly confidential.

Share to...