Apparatus for Transmitting Motion to a Distance by Means of Electrical Energy.
Year: 1898

page_text: Date of Application, 12th May, 1898-Accepted, 27th Aug., 1898
COMPLETE SPECIFICATION.
Apparatus for Transmitting Motion to a Distance by Means of
Electrical Energy.
We, SIEMENS BROTHERS & Co., LIMITED, of 12, Queen Anne's Gate, West-
minster, S.W., in the County of London, Electrical Engineers, do hereby declare
the nature of this invention (as communicated to us from abroad by Siemens &
Halske. Aktien-Gesellschaft, of Markgrafen-Strasse, No. 94, Berlin, S.W.,
Electrical Engineers), and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to apparatus for transmitting motion to a distance by
means of electricity and for producing an action similar to that produced by the
arrangement described in Specification No. 8041 of 1897 by means of a trans-
former connected with a commutator through a combination of partial pressures.
In the form of apparatus set forth in the Specification No. 8041 of 1897 the
transmitter and receiver were, generally speaking, similarly arranged. The
transmitter and receiver were supplied with alternating or rotary current excita-
tions from the same machine. By this invention it is not necessary to magnetise
directly both the transmitter and the receiver. According to the nature of the
alternating current the excitation of the one part of the transmitter or of the
receiver may be produced by induction. The advantage obtained by this, is, that
the number of necessary wires is diminished and that sliding contact may be
dispensed with for the one apparatus, since the movable part of this apparatus is
not supplied with direct current.
If an apparatus be constructed in the manner represented in Fig. 1 of the
accompanying drawings, namely with a stationary and a movable part each
carrying coils connected together as shewn at A B and C D, an electromotive
force will be induced in the coils C 1) by magnetising the fixed parts A B by an
alternating current. If the fixed coil is short circuited the movable part will
come to rest in that position in which it induces the minimum current in the
short circuited coil.
If the poles in the stationary part are shifted by any means, the position of the
movable part is shifted in corresponding degree. In Fig. 2 this is applied in an
apparatus for the transmission of motion.
P is the transmitter S the receiver. The pair of coils A B of the transmitter P
are supplied with an alternating current from an appropriate source. An electro-
motive force is induced in the pairs of coils CD and E F which dependent on
the angles which the planes of the windings of these pairs of coils make with
those of the windings of the pair A B. The receiver S has on its one part two
pairs of coils G H and I K, corresponding with the coils C D and E F, of the
transmitter P. The other part of the receiver S has a short circuited coil L M.
If the pair of coils CD are electrically connected with the pair G H, and E F
with I K the combined action of the two pairs of coils produces a combined field
the position of which depends on the magnitude of the separate pressures at the
terminals CD and E F of the transmitter. Since the magnitude of these pressures
depends on the position of the stationary part of the transmitter relatively to the
movable part thereof, the position of the field in the receiver, that is to say, the

page_text: poles formed by the coils G H and I K, depends on the position of the movable
part relatively to the fixed part of the transmitter. Taking for the sake of
simplicity the case where the coils CD and E F, as well as GH and I K, are
equal, the field-strength in the receiver, (as a simple mathematical calculation
will shew) is of a constant magnitude but the poles produced change their
position correspondingly with the movement of the movable part in the trans-
mitter. If the coil L M of the receiver is short circuited, the movable part of
the receiver always tends to come to rest in that position which induces the
mininum current in the short circuited coil. When, therefore, the movable part
of the transmitter is turned, the poles in the receiver, are shifted and the receiver
is turned to a corresponding degree. Thus movements of the transmitter are
conveyed to the receiver, and conversely movements of the receiver are conveyed
to the transmitter.
Obviously, the movable and fixed parts of the receiver and transmitter can be
interchanged. The transmitter and receiver, instead of being arranged to be
bi-polar, as shown in Figure 2 may be arranged to be multipolar. Of the four
connecting leads between the transmitter and the receiver two, say CE and GK,
may be combined so that only three connecting leads are necessary. Instead
of two pairs of opposite coils several may be used and may be connected as is
usual with rotary current coils.
Such an arrangement is shewn by way of example in Figure 3. M and m are
two alternating current motors, of which the movable parts have coils for uniphase
alternating currents, while the fixed parts have three-phase current coils. In the
transmitter M the two ends of the coils of the movable part are connected to two
sliding contacts S1 S2 to which the leads from the primary machine are attached.
The free ends of the coils of the fixed part, which coils are connected in star or
mesh fashion, are attached to the three terminals A B C which are connected with
the corresponding terminals a b c of the receiver m.
The coils of the movable part of the receiver m are short circuited so that this
apparatus needs no sliding contact. Every movement of the spindle of the trans-
mitter M will be conveyed to the spindle of the receiver m and vice versa, so that
the two apparatus behave as though they were mechanically geared together in
a yielding manner. According to the foregoing construction, in order to work
the apparatus, it is only necessary to move the poles of the receiver. In the
arrangements shewn in Figs. 2 and 3 this is done by a motor. In Fig. 4 an
arrangement is shewn in which the shifting of the poles in the receiver is effected
by means of an induction coil or a transformer and a switch apparatus or com-
mutator.
T is a transformer fed through terminals 7 and 8 with an alternating current
from the machine P. By way of example it is here supposed that the receiver M
requires a higher pressure than that yielded by the primary machine. The wind-
ings of the transformer are separated into divisions which are unequal to each
other.
The magnitude of the separate partial pressures is apparent from the diagram,
Fig. 5. The partial pressures a b, a c, ad, a c, a f, a g, are in the same proportion
to each other as are the projections of the radií a r³, a r³, a r², a, a, on the
radius a g, the angle r¹ are being equal to the angle rs ar³, and so forth.
From the terminals a b c d e f g of the transformer T leads pass to the com-
mutator U as is shewn in Fig. 4.
The commutator consists of contact arms K, K, K, K, crossing each other at
right angles and, 5 contact rings. The outermost of these consists, as to its one
half, of contact segments to which the connecting wires are attached as shewn.
The contact arms make electrical connection with the contact rings h1 h2 h3 h 4.
The contact segments of the commutator U marked a b c d e f g and corre-
sponding with the similarly marked terminals of the transformer T may have so
great an insulating space between each of them that when the contact
arms K1 K2 K3 K4 are turned the passage of an arm from one contact segment

page_text: to the next will break the circuit; or they may be arranged, as shewn in Fig. 4,
in such a way, that when an arm is passing from one segment to the next the
corresponding portion of the coil in the transformer will in the first instance be
closed by a resistance W in the known manner.
Leads are carried from the contact rings to the sliding contacts s¹³ ³ of the
receiver which consists of an asynchronous alternating current motor M. The
sliding contacts are connected with the one coil section and 34 with the
other, crossing the first vertically. The coil of the fixed part of the motor is
short circuited at the terminals. By moving the contact arms of the com-
mutator, the electrical pressures at the contact rings s¹ 2 and 3 are varied,
and the magnetic fields dependent on the separate pressures, are correspondingly
changed. The magnetic field produced in the movable part possesses constant
strength, if the partial pressures are chosen to correspond with diagram Fig. 5,
but it changes in position according to the magnitude of the pressures at the
sliding contacts ss and ss, and therefore according to the position of the
contact arms.
The movable part now always takes such a position that the current
in the coil of the fixed part, short circuited at 2, is a minimum and,
therefore, that the fields in the fixed and movable parts are at right angles to
each other.
It follows, that for each movement of the contact arms from one contact seg-
ment to the next produces a certain movement of the receiver. The arrangement
shewn in Fig. 4 has the advantage over that exemplified in Figs. 2 and 3 that
primarily only the friction of the contact arm has to be overcome in order to
effect a secondary movement of any desired degree of energy. The subdivision
of the pressure ay may be carried to any desired extent; the greater the sub-
division the smaller can be the changes in position effected in the receiver M.
Obviously, the receiver may have several crossing coils, in which case the
commutator must be correspondingly arranged.
The arrangements described and shewn in Figs. 2 to 4 are especially advan-
tageous if the number of connecting leads from the transmitter to the receiver
cannot be great, they are practically applicable for the transmission of slow
movements, where the electromotive forces generated by movement of the movable
part are negligable as compared with the electromotive forces induced from
without.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1. In apparatus for transmitting motion to a distance of the kind herein
referred to, the substitution in the receiving instrument, for the fixed or movable
coils which are supplied with current from without, of fixed or movable short
circuited coils or groups of coils which are only capable of producing pulsating
but not rotating fields, substantially as described.
2. In apparatus for transmitting motion to a distance such as is herein referred
to and in which the receiver is arranged as set forth in the First Claim, the use
for the transmitter of an induction coil or transformer in combination with a
commutator by means of which the alternate current pressures in the movable
part are so changed as to amplitude that in the receiver the position of the poles
and that of the short circuited coils vary so as to cause the movements of the
receiver to correspond with those of the transmitter, substantially as described.
Dated this 12th day of May 1898.
ABEL & IMRAY,
Agents for the Applicants.