The industrial revolution's main prerequisite is not a converter or any other clever device. It's about power sources. When you've got e.g. a bunch of coal that gives off lots of thermal energy, finding ways to transform that energy (with engines, factory machining etc) becomes a hot open engineering contest with good solutions being a matter of years, and optimal ones, of decades or centuries (i.e. much longer than Roman history).
But if you ain't got the energy, then making any devices, however clever, isn't going to change the tide. Antique and medieval civilizations had some rather elaborate mechanisms like the antikythera, the trebuchet, rapid-fire crossbows in China etc. But without a major source of low-cost energy, none of them succeeded with an industrial revolution: large-scale coal-mining was what did it in the end.
> When you've got e.g. a bunch of coal that gives off lots of thermal energy, finding ways to transform that energy (with engines, factory machining etc) becomes a hot open engineering contest with good solutions being a matter of years
Not really; people had bunches of coal giving off lots of thermal energy forever. They used it in the obvious way, burning it for heat in winter. This didn't lead to much in the way of technological advance.
> and optimal ones, of decades or centuries (i.e. much longer than Roman history).
How is "centuries" "much longer than Roman history"? Roman history goes on for more than 700 years, and that's just the history of Rome as a major international power centered on the city in Italy. The Byzantine Empire, or -- as it called itself -- the Roman Kingdom, with extensive cultural and institutional continuity, went on for another 1000 years after that.
And all of that generated about 5 hp (3.7 kW), at about 1-3% efficiency of thermal energy to motive power.
Watt's engines were about 10-20 hp, and about 10% efficient. Peak efficiency of a triple-expansion steam engine approached 25%. The best thermal engines today (combined-cycle steam turbines) approach 50%, and have a far better power-to-weight ratio.
Well I think it is more about the human power sources.
Only the usage of more efficient crops like potatoes and the import of fertilizer like guano enabled the people of the industrial revolution to work in factories instead on the fields.
No pre industrial civilization was able to feed so many people not working in agriculture.
But if you ain't got the energy, then making any devices, however clever, isn't going to change the tide. Antique and medieval civilizations had some rather elaborate mechanisms like the antikythera, the trebuchet, rapid-fire crossbows in China etc. But without a major source of low-cost energy, none of them succeeded with an industrial revolution: large-scale coal-mining was what did it in the end.