If someone already built it then he has not published his results on the forums I am aware of.
I would suggest building it for yourself. You may know Mindfreer's old channel, albeit back then he asked USD 29.95 for a pdf file that included his own build details. This was his channel https://www.youtube.com/user/MindFreer/videos
Back then I tried to persuade him for looping back some part of the output power to the input motor because in this video https://www.youtube.com/watch?v=c4FEba4kQb0
his meters showed approximately 182W output versus 97W input (see this in the Comment section well under the video) :
Q "@MindFreer Have you connected your inverter's AC output (117-118V) to the motor input for a possible looping test? (This would be the ultimate test for showing real "overunity".) Let the 12V battery in the loop because it acts as a voltage stabilizer against a runaway situation. Also, could you make another video where you show the two 100W light bulbs 'shining' ?"
A "@gyulasun Yes. That was one of my first experiments when I completed this setup. It ran fine for a few minutes then suddenly, it unexpectedly started consuming an incredible 600 watts until all the power in the battery was consumed and then the alternator shorted out, because you can't power anything directly off of an alternator. I think it might need more stabilization than just the battery."
Well, this was a 'interesting' answer, so next question:
"@MindFreer Thanks. My further questions: 1) What do you mean on the alternator shorted out? It simply went wrong, its windings burnt down? 2) Would like to know the battery capacity in AmperHour you used? 3) Earlier you had another video on the CT transformer too, why did you take it off?"
A: @gyulasun 3) YouTube deleted my other 2 videos on how to build your own Free Energy device. They did so without explanation or any recourse for me: Internet Censorship. One was my Current Transformer video and the other that included plans for the above device. You can still buy these plans at the Water4gas website. YouTube does not like Free Energy, and that is a fact, not a "conspiracy theory" as it undermines the whole Petro-chemical machine the world economy currently revolves around."
One more answer from him:
gyulasun 1) I'll have to do a video demonstration of this phenomena as it keeps coming up as a question. You can't hook a load directly to an alternator. I know because I tried when I first setup my device. The alternator will not produce power, instead it just makes this kind of muffled buzzing noise. My battery supplier told me the alternator was shorting out and I had to hook up a battery to it and put my load on the battery. 2) Google:"Xstatic Batcap model 2000" for info on my battery"
Well, there is no way to figure out from his answer what was the truth, perhaps he did not have good enough knowledge for looping... or he did but the setup bogged down by whatever reason, and he still tried to collect some money from his own build plans.
See here his advertisement site from the year 2011 with the help of the internet wayback machine (it does not show up directly any more):https://web.archive.org/web/20110405202731/http://www.water4gas.com/Free-Electricity-Magnetic-Cogging-Device-You-Can-Make-For-Fun-and-Profit.html
If you feel like spending time and money on this then try building it (I mean in his other videos he showed some details). And also, you can find hints here: http://www.rexresearch.com/hatem/hatem.htm
PS Regarding his other "Free energy machine" with the Current Transformer (CT) is another setup what he had the videos removed, I can explain how he thought it working if you are interested, it was "tricky".