Another possibility is to interpret the photograph in the newspaper article, above, to speculate that the two spheres were not connected by a common copper tube, and were not conveyed down into their drum into an iron core devoid of copper windings, but were -instead- carried downward into their drum each copper tubing isolated from the other and each electrically connected to two separate locations on a transformer housed inside of that drum...
There are seemingly infinitely various ways of applying this simple concept of a capacitor|sparkGap|capacitor sandwich to various circuits which will make use of them in an overunity manner, ie. deriving a magnification of output from a miniscule input via electrical reactance.
It is also easy to see that this last simulation is capable of manual operation not requiring complicated electronics such as what exist in modern electric vehicles to control the motor's operation. Given the fact that such supportive circuitry did not exist 100 years ago, it seems highly unlikely that the Ammann brothers implemented their concept any other way than this.
For, it becomes obvious that their accelerator pedal in their EV conversion may not have operated as anything other than an ON/OFF switch engaging, and disengaging, an electrical short to suspend the reactive surges from time to time and, thus, manually impose a periodicity to those surges whose average output may have satisfied their motor's requirement for power.
Because of the nature of reactive power to surge, or diminish, at an exponential rate, an accelerator pedal becomes useless since acceleration is already occurring when the car's accelerator pedal is engaged.
Thus, pumping the accelerator pedal would have been the prefered method of its operation (as far as I can tell).
This last circuit simulation satisfies this last requirement in that these surges are slow enough to be manually regulated by the driver.
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BTW, the "mineral" mentioned by C. Earl Ammann in the newspaper article was probably alumina, aluminum oxide, whose crystalline equivalence is the category of minerals known as corundum whose various formations are: ruby and sapphire, etc. If placed on the anode of an electrolytic battery, it becomes a diode. If placed on both opposing plates surrounding a dielectric, it becomes a capacitor.