According to the law of conservation of energy, it will not rotate. The efficiency of water electrolysis is not high, and only 70% of the electrical energy is converted into chemical energy at most. The combustion efficiency is also very low in an open environment. The efficiency of combustion under closed pressure in an internal combustion engine is less than 40%. The combustion method of this machine has a maximum efficiency of 20%. In addition, the efficiency of the generator is not 100%, and there are also losses due to mechanical friction. The final efficiency is around 0.05%, i.e. the electrolytic cell consumes 100 kilowatt hours of electricity and the generator can only produce 5 kilowatt hours of electricity in the end. It is impossible to function alone. Of course, you can turn it on and use it as a rotating decoration.
1 cubic meter of hydrogen has a mass of 89.9 g and a heat of 14.3 × 10,000 ×89.9 = 12,855.7 kJ. The efficiency of electrolytic hydrogen production is typically around 55%. The hydrogen meter is: 12855.7kJ/55%=23374kJ, the time required for electrolysis with a power of 100W: 23374kJ/0.1=233740s=65h (hours)