patented by Hermann Gläser  in 1889 was popularized by
Lewandowski and others in several articles -, and was cited as
"Lewandowski machine" in some texts -. The
the attention of several researchers working with electrotherapy
by the end of the XIX century, as being compact and insensitive to
machine was composed of two hollow ebonite cylinders T-T1
assembled so they turn in opposite directions one inside the other at
small distance. Mounted fixed in the central axle e-f was a pair of
metal combs forming a neutralizer circuit in vertical orientation (see
below). At the horizontal diameter of the cylinders, outside, two
charge collectors with metal combs Sk-Sk1
were positioned, connected to the machine's terminals m-n. The driving
mechanism used a pair of large pulleys H-H1
turning in opposite directions, driving small pulleys r-r1
by belts, connected to the outer and inner cylinders by ebonite tubes.
Two gears b-b1
were used to invert the directions of rotation of the two lower axles W-W1,
one of them driven by a crank k.
A cross structure a-b-c-d
above the cylinders was used to keep the assembly of the charge
collectors and terminals firm.
The machine apparently works as a cylindric sectorless Wimshurst
machine without the usual terminals, with the
output taken at one of the neutralizer circuits, interrupted by the
spark gap. It requires excitation to start, usually a charged
ebonite rod electrized by friction, brought close to the cylinders
above or below them while the machine turns. A photo of an original machine of this kind can be
found in the collection here.
Several papers and books (see some references below) show engravings
similar to the ones shown here .
By November 2011 I
started to build a
small version of this machine to
see how it works and maybe later build a greater version. For the
cylinders my initial idea was to use sections of PET bottles of
diameters, in an attempt to find an use for that material, that is
highly insulating and easily available, although not resistant to heat.
For the lateral
disks I used HDPE cutting boards, turned on the lathe for a tight fit
inside the cylinders, and fixed to them with three screws each. The
small pulleys and tubes were made of nylon and were fixed to the
lateral plates by screws. The structure was planned with HDPE plates
and brass rods for
most parts, following the original idea but with a simpler driving
mechanism, similar to the one of a classical Wimshurst machine, with
direct and crossed cords in two sets of pulleys to make the two
cylinders rotate in opposite directions over the fixed central axle.
cylinders (left) and plans for the complete machine (right).
The machine used in
machine could be tested before the construction of the terminals.
Excitation was provided by connection through the terminals with
another machine. Initially it only worked, alternating polarity
periodically, while the other machine was working. This behavior could
indicate that the charge multiplying mechanism had insufficient gain
due to the distance between the cylinders. The internal cylinder
was then rebuilt with larger diameter, by using a PET strip with an
overlapped joint instead of a continuous cylinder, cut from another
bottle as the one used for the external cylinder. The distance between
the cylinders was decreased from 7 mm to 2.5 mm. I suspected that
this would not be a problem, and apparently really wasn´t.
machine then worked, also alternating polarity but continuing after the
exciting machine had stopped. It worked better with Leyden jars
connected to the terminals. A better excitation method was to place two
electrodes, one above and other below the cylinders, at small distance,
connected to the exciting machine. The machine then could work with the
terminals short circuited, and could keep excitation for indefinite
time after the disconnection of the exciting machine without polarity
reversal and would retain charge and restart if stopped for some time.
But with the terminals open
it would stop immediately. This is the expected behavior for a
sectorless Wimshurst machine with only the neutralizers mounted. The
operation reported in the old articles was then not observed in this
machine. Maybe due to different materials used or the small size, but
the structure of the machine really doesn't look reliable. With the
terminals short-circuited, current could be drawn from the two
quadrants of the cylinders where polarities are identical, without
stopping the operation. This indicated that the machine could be made
work with the addition of an external neutralizer circuit, providing a
short-circuit over the surface of the external cylinder after it passes
under the output charge collectors, essentially converting it to a
cylindric sectorless Wimshurst machine with the output at the outer
cylinder only. To avoid the need of external excitation, at the expense
of smaller output power, sectors
and brushes could be added, forming a sectored Wimshurst machine.
Something to be observed is that the original descriptions require the
cylinders to be air-tight, while articles about other cylindric
machines stress the need of removing air full of ozone and nitrogen
oxide from the interior of the cylinders. This question will be
answered by observing how the machine behaves after some time.
Concluding that the original idea was not reliable, I added 16 sectors
to each cylinder and
an external neutralizer, with brushes of thin ni-cr wires at the
internal and external neutralizers, and completed the terminal
assembly. The resulting machine works reasonably well, but is
not powerful. It starts up immediately, is insensitive to
produces sparks with up to 1.5 cm between the 1.8 cm terminal balls
generates about 3 µA of current between one terminal and the
neutralizers with the crank turned at 3 turns/second. The clearances
would allow about 6 cm of spark length,
but something impedes enough rise of the output voltage, probably the
brushes at the neutralizers, that would be far from the terminals in a
conventional plate machine, but are quite close in this compact
cylindric version. The charge collectors made from serrated brass foil,
are also not good at retaining charge, due to corona at the edges, and
really corona can be seen at the external edges in the dark. The PET
may have some
characteristic causing this too. With so low current output any loss
impedes the voltage to rise. I tried to reinstall the original inner
cylinder, with sectors, to see if the joint in the substituted cylinder
was causing some problem. The machine works with it, but is even more
investigations will still be done with the structure,
trying to find the losses that are impeding further voltage rise.
interesting property of the machine is the relatively good insulation
of the neutralizer assembly, which is floating, what allows the machine
to operate with one terminal grounded, with the voltage at the other
terminal doubled and the neutralizers at half the voltage. The video
below shows this. When I touch one of the terminals the voltage at the
other rises, and voltage of the same polarity and about half the value
appears at the neutralizers.
 H. Gläser, "Static induction machine," U. S. patent no.
401156, April 9, 1889.
 R. Lewandowski, "Ueber eine neuartige Influenz-Elektrisirmaschine,"
Wiener Medizinische Presse, Nr. 23, col. 833-836, 1888.
 K. "Die Gläser'sche Influenz-Elektrisirmaschine,"
Elektrotechnische Zeitschrift, pp. 452-453, October 1888.
 R. Lewandowski, "Nouvelle machine à influence," Cosmos:
revue des sciences et de leurs applications, Volume 11, pp. 148-150,
 R. Bielschowsky, "Ueber Influenz-Elektricität und die neue
Influenzmaschine von Gläser in Wien," Therapeutische
Volume 3, pp. 107-112, 1889.
 Henry McClure, "An international system of electro-therapeutics,"
Horatio R. Bigelow, Rebman, London, 1894.
 William Edward Steavenson, Henry Lewis Jones, "Medical
Electricity," P. Blakiston, Son & Co., Philadelphia, 1892.
 Thomas Stretch Dowse, Lectures on massage & electricity in
treatment of disease (masso-electrotherapeutics), Treat, 1890. Created: 31/12/2011
Last update: 2/1/2012
By Antonio Carlos M. de Queiroz
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