For example, having battery with high (few megaohms) series resistance, is it possible to convert mechanical energy to current at that battery's voltage?

Or in other words, if I have low voltage, high current generator like homopolar generator, is it possible to use high impedance voltage source (battery with high resistance or an electret) to increase the generator output voltage?

The question basically is: is there a generator that utilizes external electric field in addition to conventional magnetic field. Conventional generators utilize electromagnetic induction (changing magnetic field) or magnetic field part of Lorentz force (Laplace force). I'm asking about a generator that utilizes both magnetic and electric field.

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    \$\begingroup\$ You may have to re-word your question and add a diagram showing what you want to do along with the reason why, because it's not at all clear to me. \$\endgroup\$
    – John D
    Jun 6, 2017 at 21:24
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    \$\begingroup\$ It sounds like you are asking if a low-voltage, high-current generator can be combined with a high-voltage, low current source to make a high-voltage, high-current source. You can not get more power than the sum of the two. If you connect them in series, the current rating will be the lower of the two. If you connect them in parallel, the voltages would need to be matched. Using electronic power conversion circuits, a wide range of AC and DC sources with various voltage, current and frequency ratings can be combined to a common grid. \$\endgroup\$
    – user80875
    Jun 6, 2017 at 22:30
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    \$\begingroup\$ A variety of electrically and mechanically interconnected rotating machines and transformers could conceivably be used to combine a variety of AC and DC sources to supply a single grid. \$\endgroup\$
    – user80875
    Jun 6, 2017 at 22:35

1 Answer 1


The question basically is: is there a generator that utilizes external electric field in addition to conventional magnetic field.

Since that is not a concept that is routinely covered in text books, the question must be whether or not the concept is practicable or has ever been explored or proven. Since this is actually two concepts, one of which appears to be the dual of the other, it might be useful to consider the combination of two machines. Since the electrostatic machine would tend to operate at a high voltage and low current while the electromagnetic machine would tend to operate at a low voltage and high current they could not easily be connected together electrically. That would tend to indicate that the two concepts can not usefully be combined in one machine.

There are many electronic power conversion products available for creating electrical grids and microgrids that combine a variety of electric power generating sources. Combining an electrostatic machine with an electromagnetic machine in that manner is certainly practicable.

Some recent macro scale electrostatic machine research is described by: B. Ge; A. N. Ghule; D. C. Ludois, "A 3D Printed Fluid Filled Electrostatic Rotating Machine Designed with Conformal Mapping Methods," in IEEE Transactions on Industry Applications, 09 May 2017 Vol. 52(3), pp. 2156-2166.

The above paper identifies 13 electrostatic machines that were constructed between 1933 and 2016 and provides references to the associated research. The list consists of ten macro-scale machines and three micro-scale machines. The list includes the speed, torque, voltage and design concept for each machine.


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