Oh dear... magnets.
Right, listen up. No energy conversion process can ever be >100% efficient. Some energy is always lost to heat and friction. The second law of thermodynamics has been shown exhaustively to work like this since William Thomson (later the Lord Kelvin) and many others worked it out in the 1840s. This is mainstream physics, taught, demonstrated and tested to destruction in every undergraduate physics or engineering course. As XKCD have on their marvellous t-shirt, "Science: it works, bitches"
For this machine to be 500% efficient, for every calorie it takes in, it must produce 5 calories. This is nonsense. You can't
make energy, only convert it between forms (including matter). So, if it works, this machine must be converting itself from matter to heat, which is VERY inefficient indeed!
Tediously, at some point, Tesla always seems to be invoked in these discussions. It's almost like a version of Godwin's Law (look it up - it's fun to look things up). Tesla may have been a genius but he was also something of a crank. He may have demonstrated power transmission in 1890-something, but he was also making pronouncements about things that simply can't work for the very reason that they
don't work. The best one can say is that he did a lot of thinking and some of it was good, but the rest was nonsense. There was no conspiracy to keep his "free energy" work suppressed. He was strange to start off with, but increasingly severe OCD made him a nightmare to work with. He became obsessed with the number 3 and spent considerable amounts of time finding and nursing sick pigeons, for example. Funds from his European patents dried up at the outbreak of WWI and the tower he built to experiment with energy transmission was demolished so it couldn't be used by German spies. His condition, outbursts and general lack of research rigour left him ostracised by backers, industry and science. He died, bitter and penniless due to those factors.