Review on Wathai Industrial Bearing Brushless Cooling by Jeremy Gums

This review is for Wathai's 120mm x 38mm EC fan. I bought two of these to replace two old 22w shade post fans (no cupcakes) that I installed on top of the back of my wood stove. Using a Ponie PN1500 power monitor, I found that the old high speed fans had a total power draw of 38 watts. I started looking for more efficient fans as they often run for days. A study of traditional AC cupcake fans found they are no better for lower power consumption. It turns out that typical inexpensive AC muffin fans also have a shielded pole motor design. I've thought about using brushless DC fans (BLDC), but then I would need a switch mode power supply (SMPS) to convert the AC power to the DC voltage that suits them. I also found that using 48VDC BLDC fans with SMPS would be the more efficient way. However, those efforts led me to newer fans being developed by EC. It's basically a 48V (or maybe 60V) BLDC fan with integrated SMPS that runs directly offline (no AC transformer) to convert AC to DC. With PWM, an EC fan can handle a very wide range of AC input voltages (by design they should also be able to handle the same range of DC input voltages as many SMPS; but I haven't found any manufacturer claiming this). I tested the new Wathai fans individually outdoors with a pony. The first fan showed 3.74W at 121.3VAC and 0.05A (PF 0.60) and the second fan showed 4.17W at 121.4VAC and 0.06A (same 0.60pF) . This is a big improvement over AC cupcake fans of the same size and airflow capacity, which draw around 20-30W each. Based on these numbers, the two new Wathai fans should pay for themselves in just one heating season through reduced power consumption. Interestingly, when two fans were switched in parallel for my application, the performance of the pony fluctuated between 0.05-0.1 watts. Performance figures were very consistent when testing one fan at a time. Overall, the build quality is very good. The included mounting screws are long enough to fit through a 1/8" thick mounting surface, the included grille, and both sides of the fan. The fan housing is plastic, not aluminum; but I don't have any of the cheaper aluminum-framed EC fans The power cord is 48" long (if you count the length of the plug pin it's 49") of good quality, but constructed with only 20-22 gauge wires. If you're not using a fan cord, I'd recommend it Due to the small amount of wiring, the cable is only suitable for a maximum output of 30-40 W. The grille is beautifully made and in shiny aluminum chrome color as shown (I would have preferred black grilles but didn't find this option). The supplied connector clamp does the trick but I went further and soldered/shrunk the power cord from the old fans for my application I have several flaws on the Wathai fan found. I couldn't find any UL, CE or other international certifications for the fan or power cord. There is also no IP classification. Lock washers are not included. Most EC fans like Wathai currently only run at one speed. I could find PWM/0-10Vdc variable speed from other brands; but they were 2-4 times more expensive. The power cord that comes with the fan doesn't have bare wire ends ready to clip into the clip, so you'll need to do that when you get the fan. There are no instructions or specs with the fan, although it should be easy enough to set up/install for most people. There is no model/serial number (or current rating, like most cupcake fans) on the fan tag, so I'm guessing Wathai only offers this model in that specific size. Finally, as another reviewer pointed out, there's RFI from the fan. My portable AM radio made a noticeable buzz over most of the AM band when I brought it within a meter of the Wathai fan. My TV, about 10 feet away, showed no problems with the fans and is on the same circuit. So pay attention to your application; This fan may not be the right choice for you. On the positive side, the fan moves air similar to the 100 CFM DC fan I compared airflow to and the Wathai fan is pretty quiet. I'm pretty sure it matches the advertised dB noise level. Plus, the price is so comparable to old, inefficient AC cupcake fans that it's worth buying because they'll save you enough power to pay for itself in no time. Overall, I am very satisfied with the Wathai 120x38mm EC fan. to buy. So far I've only used them for a week; but if the bearings last up to 60,000+ hours I'll easily justify my money.