CFM-70C datasheet(7/8 Pages) CUI

7 / 8 page

date 10/15/2021

│ page 7 of 8

CUI Devices

│ SERIES: CFM-70C │ DESCRIPTION: DC AXIAL FAN

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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

operating and VFG or VCE depending on the locked rotor position when fan motor is locked (See Figures 1~2 below).

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.

Output Type: Open Collector

Vs: (VFG)

5 V fan: 3.3~5 V

All others: 3.3~15 V

Ic≤5 mA

R≥Vs/Ic

VCE(sat)≤0.5 V

4 Pole Motor

N=RPM

T=60/N (sec)

FG=1/T*2 (Hz)

N=FG*30

Additional Resources: Product Page | 3D Model

CFM-70C Arkusz danych(PDF) 7 Page - CUI INC