Delta (AFB1212SHE) Fan Testing

Summary

This blog covers some basic measurements of the Delta (AFB1212SHE) DC brushless fan with a possible use of the fan for computer cooling.

Delta AF1212SHE DC Brushless Fan

Hardware Setup
To perform measurements of the current drawn by the fan across and a range of input voltages, the displayed values on from a Rigol DP832 power supply were utilised. For the tacho measurements a Cypress CY8CKIT-049 development board was employed to convert the tacho output from the Delta fan into a corresponding RPM value.

CY8CKIT-049 - Courtesy Cypress Semiconductor

For the PSoC input a pullup resistor (4k7) was connected between the 5V DC supply and the input pin.

PSoC - Delta AFB1212SHE Test Bed

PSoC Tacho Measurement
The tacho measurement solution utilised a one second sampling window to count the number of pulses. While the measurement solution does have some level of jitter, this was unimportant as the measurement was for indicative purposes.

PSoC Tacho Measurement

The website documentation for the Delta brushless fan, AFB1212SHE-F00 shows that the fan has 4 poles and two pulses are seen for each complete rotation of the fan. The image below is taken from the fan datasheet.

Delta AFB1212SHE Tacho Output

The Cypress Timer_3 component performs all the counting and is configured to count on rising edges. A copy of the project is available at the end of the blog for anyone wanting to review and improve the design.

PSoC tacho Timer Component Configuration

Measurement results of the fan speed were made available on the Kitprog serial connection. 

Measurement Results
While varying the input voltage across the operating range listed on the Delta website, the fan speed was calculated and output to a serial monitor. The DC power consumption was calculated and plotted against the fan speed. 

Shown in the graph below is the almost linear relationship between input voltage and fan speed.

Delta AFB1212SHE Input Voltage vs Fan Speed and Power Consumption

The data listed below represents the points in the graph above. There is also one addition to the table which is Measured RPM. This value was derived using the period of the Tacho waveform to verify the error in the PSoC software measurement.

Measurements with Delta AFB1212SHE