date 05/19/2021

│ page 6 of 7

CUI Devices

│ SERIES: CFM-92S │ DESCRIPTION: DC AXIAL FAN

cuidevices.com

APPLICATION NOTES

Auto Restart Protection

When the fan motor is locked by an external force, the device will temporarily turn off electrical power to the motor and

restart automatically when the locked rotor condition is released.

Tachometer Signal (Yellow Wire)

The tachometer signal is for detecting the rotational speed of the fan motor. The output will be a square wave when fan is

Figure 1: Tachometer

Output Circuit

Figure 2: Tachometer

Output Waveform

Polarity Protection

Able to withstand 10 minutes of reverse polarity connection between the positive and negative wires without causing

damage.

Figure 3: Soft Start

Soft Start

When the fan power is on, the current will increase slowly (~15 seconds) until the fan reaches the rated speed.

~15 s

t

Rated

Current

Output Type: Open Collector

5 V fan: 3.3~5 V

All others: 3.3~15 V

Ic≤5 mA

R≥Vs/Ic

4 Pole Motor

N=RPM

T=60/N (sec)

FG=1/T*2 (Hz)

N=FG*30

Additional Resources: Product Page | 3D Model