Check this out;
Patent applications on such devices are so numerous that the patent office instituted a rule that perpetual-motion machine concepts had to be accompanied by a model that could run in the office for a period of one year: Antigravity Machine Patent Draws Physicists' Ire

I can tell you first hand that moving parts need maintenance. NASA developed self lubricating gears and bushings in the 60/70’s, but making your own would require a well equipped shop not accessible to most.

I kinda suspect that both sides of the energy issue are pulling the wool over our eyes. I can light a flash-light bulb for a week using sea water and a beer can!!!
By-the-way, did you know you don’t need $20.oo worth of electricity to charge the batteries in an electric car to go 50 miles? You need to change the acid @ about 35 bucks for a 55 gallon drum and the lead plates once a month @ .12 cents a pound.

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Only a liberal would know how hard it is to get a nicotine patch to stick to a monkey.