There are affordable plans for this that have circuit board diagrams on open source.
Just buy the manual from the links below and you can read about it and build your own with 2 motors.
The inventor/writer of the plans built his and put it in one of his remote locations and the electric company came out several times to change the meter because he was not using/wasting enough electricity.
I know him personally and am looking for someone to help build a board, since my specialty is the medical field and electronics do not make sense to me. If you can build a 100V circuit, I'll buy one if it is not too expensive and I'll hook it up to my house through and extra electric meter and let you know how it works.
He also has many fuel saver manuals and others and you can also buy a browns gas HHO torch kit to experiment yourself.
I have one of the er50 kits and charge my water daily.
Thanks and enjoy your experiments.
https://www.eagle-research.com/cms/af/nomad181  then purchase "Reverse Your Electric Meter" for a mere $12