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Rexflo DF12123025BH-PWMG

The 120mm DF12123025BH-PWMG fan from Rexflo is shipped in a modest-looking package with a transparent front. The product specs are listed on the back side:

The fan comes without any accessories. It is manufactured in China and has a recommended price of $20. Its warranty period is 1 year.

The Rexflo DF12123025BH-PWMG looks most conventionally with its black frame and 7-blade impeller connected with four spokes:

 

The impeller and electromotor are 110 and 44 millimeters in diameter, respectively. Three of the fan spokes are 5 millimeters wide; the cable spoke is 7 millimeters wide.

The impeller has seven blades that get wider towards the ends and have a sharp front edge.

The interior of the frame is curved, promising a low level of noise. Well, this fan can hardly be called quiet because the rotation speed of its impeller, controlled via pulse-width modulation, is 1000 to 2600 RPM. The air flow is declared to be 36.9 to 96 CFM and the noise level, 21.9 to 42.6 dBA. The static pressure is not specified.

The fan sticker tells you the model name, voltage and current, and the country of origin. According to my measurements, this fan has a start-up voltage of 5.4 volts and a peak power draw of 2.8 watts. Its dual ball bearing is expected to serve for 50,000 hours. The 4-wire cable is 300 millimeters long.

You can find the test results of the Rexflo DF12123025BH-PWMG in the next section.

Rexus TopMotor DF121225BH

The TopMotor DF121225BH comes in OEM packaging without any accessories. Its design is identical to that of the fan from Rexflo (see the previous section).

 

The frame, the impeller, everything is the same as in the above-discussed Rexflo DF12123025BH-PWMG.

However, the recommended price of the TopMotor DF121225BH is almost twice lower at $11.

The key difference of the Rexus from the Rexflo is the lack of PWM-based speed control. This must be why they differ in price. Thus, the rotation speed of the TopMotor DF121225BH is constant at 2600 RPM. The air flow and noise parameters are the same but Rexus also specify the static pressure for their fan at 4.8 millimeters of water (this is the second highest specification among the tested fans).

The Rexus’s sticker is but slightly more informative than the Rexflo’s.

The bearing type and service life are identical to those of the Rexflo but the electric specifications are different. The peak power consumption is twice as high at 7.8 watts. Although not as high as the specified value, the actual power consumption of the fan as measured by me was indeed twice that of the Rexflo at 5.32 watts. The start-up voltage is 4 volts. The length of the 3-wire cable is 430 millimeters.

Now let’s see how different the outwardly identical fans from Rexus and Rexflo were in my practical tests:

Once again two seemingly identical fans perform differently in tests. The Rexflo model is the better of the two, supporting a wider range of speeds and being more comfortable in terms of noisiness. Although the Rexus can occasionally pump somewhat more air, the rotation speed being the same, this small advantage is negated by its irregular noise. Both models are very far from the leader of this test session.

 
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