AN IMPROVED ELECTRO- MOTOR
Year: 1882

page_text: LETTERS PATENT to Moritz Immisch, of 119 Toriano Avenue, Camden Road,
in the County of Middlesex for an Invention of "AN IMPROVED ELECTRO-
MOTOR"
->
PROVISIONAL SPECIFICATION left by the said Moritz Immisch at the Office
of the Commissioners of Patents on the 30th September 1882.
MORITZ IMMISCH, of 119 Toriano Avenue, Camden Road, in the County of
Middlesex, "AN IMPROVED ELECTRO-MOTOR
"
This Invention relates to an improvement in that class of elctro-motors [sic] in
which the number of armature magnets is so proportioned to the number of field
magnet poles that each armature magnet should at any given moment occupy a
different place in the magnetic field as compared with the rest of the armature
coils, the object being to obtain an equal pull and uniform action.
I employ three armature magnets of the well known T form, and field magnets
forming four pole pieces, with the similar poles opposite each other.
.
The coils of the armature magnets are similarly wound and the ends of the coils
are connected with a commutator.
Two pairs of contact springs or brushes are employed, one pair to lead the
current. to the commutator and the other pair to take it off.
.
The commutator and brushes are so arranged that the polarity of each of the
armature coils is changed four times in one revolution. Besides this each of the
armature coils receives four times in one revolution a double amount of current,
just when the magnets are in such a position of the magnetic field when this double
current is most conducive to procure rotary motion.
.
:
The four pole pieces may be formed of four sections of a ring; these sections may
be either circular or of a horse shoe shape, the wire being wound in such a manner
that similar poles are formed opposite each other. Or two straight electro-magnets
may be employed, their poles being placed in a like manner.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Moritz Immisch in the Great Seal Patent Office on the 22nd March
1883.
MORITZ IMMISCH, of 119 Toriano Avenue, Camden Road, in the County of
Middlesex, "AN IMPROVED ELECTRO-MOTOR "
This Invention relates to an improvement in that class of electro-motors in
which the number of armature magnets is so proportioned to the number of field
magnet poles that each armature magnet should at any given moment occupy a
different place in the magnetic field as compared with the rest of the armature
coils, the object being to obtain an equal pull and uniform action.
I will first proceed to describe my invention as applied to a motor in which
there are three armature magnets of the well known T form, and field magnets
forming four pole pieces of alternating polarity.
The coils of the armature magnets are similarly wound and the ends of the coils
are connected with a commutator.
Two pairs of contact springs or brushes are employed, one pair to lead the
current to the commutator, and the other pair to take it off.
The commutator and brushes are so arranged that the polarity of each of the
armature magnets is changed four times in one revolution. Besides this, each of
the armature coils receives four times in one revolution a double amount of current,
just when the magnets are in such a position of the magnetic field that this double
current is most conducive to procure rotary motion.
The four pole pieces may be formed of four sections of a ring; these sections
may be either circular or of a horse shoe shape, the wire being wound in such a
manner that alternating poles are formed in the ring. Or two straight electro-
magnets may be employed, their poles being placed in a like manner.
But in order that my invention may be fully understood I will proceed to
describe the same by the aid of the accompanying sheets of drawings, in which
Fig 1 is a plan view of one form of the improved motor, and Fig 2 is a transverse
section of the same taken partly through the field magnets and the armature
magnets and partly through the commutator. In Fig 2 only one of the coils of the
field magnets, and one of the coils of the armature magnets are shown in section,
but it will be understood that all the field magnets, and also the armature magnets
are similarly provided with coils.
A, B, C are the cores of the armature magnets; 1, 2, 3, 4 are the brushes or
contact springs, 1 and 3 forming one pair, and 2 and 4 the other pair. These
brushes are in frictional contact with the commutator, consisting of twelve segments,
six of which are visible in Figs 2 and 3, viz: a and a¹; 6 and 6'; and c and c'.
These segments are connected to the ends of the wires of the armature coils in the
manner shown in Fig 3, the outer ends of the coils being connected to the
. segments a¹, b and c', and the inner ends to the segments a, b and c. These six
segments are each and singly in metallic connection with one of another series of
six segments as shown in Fig 5, where, in order to more clearly illustrate the same,
the commutator is represented as developed or spread out in the form of a flat
band. It will be seen that those segments of the two series which are metallically
connected with each other are indicated by similar letters in both series.
Fig 4 is a side elevation of Fig 3 and shows a suitable manner of constructing
the commutator. The segments are laid on a cylinder of insulating material and
fixed by rings Y and Z, also of insulating material. There are six screws in each
ring, those in ring Y serving to press the ends of the connecting wires against the
6
1

page_text: segments, the wires, themselves then passing under the segments (as shown by the
thick dotted lines in Fig 5), to the other side of the commutator, and are there
connected to the proper segments by the screws in ring Z. The latter screws are
also in connection with the ends of the armature wires. With the exception of the
metallic connections shown and above described (and which may be effected in
any other convenient manner), the segments are well insulated from each other.
Each of the brushes makes contact with the two series of segments, those
brushes which lead the current to the commutator being metallically connected
together, and those which take the current off being also metallically connected
together. Calling brushes 1 and 3 positive, and brushes 2 and 4 negative, it will
be seen by Fig 2, that the current enters the commutator by two of the brushes at
opposite points and is taken off the commutator by the other two brushes.
In Fig 5 the contacts of the brushes with the commutator are represented by
the vertical lines 1, 2, 3, 4.
It will be seen that by brushes 1 and 3 the positive current enters segments
c, a, b and c, and is taken off by brushes 2 and 4 from segments b, a, c¹ and c'.
Thus magnet C is excited by double the amount of current as compared with A
and B, the segments c, c, being in contact with the halves of two positive brushes,
and the segments c¹, c¹, with the whole of a negative brush.
Supposing the commutator to have moved towards the left of a revolution,
the brushes remaining stationary, a positive current will then enter by the
segments a, a, c and b, leaving by segments a, b', c¹ and a, showing that now
magnet A gets the double current, while B has changed polarity. A further
development of the changes occurring during the rotation of the commutator is
shown in Fig 6, in which diagram No 1 represents the commutator as having
moved another twelfth part of a revolution towards the left, when a double current
enters coil B while C has changed polarity. In diagram No 2 of this same figure
the commutator is shown as having again moved one twelfth of a revolution and
the coil C is again receiving a double current, as in the first instance, but its
polarity is of the opposite sign to what it then was.
When the polarity of the brushes is reversed (which can be easily done by
means of an ordinary commutator switch) the motion of the armature will also be
reversed.
Fig 2 shows the armature magnet A at the point of changing its polarity. If
the armature turns to the right C is on the point of getting the double current
which is just leaving B, while if the polarity of the brushes were to be reversed, so
as to cause the armature to turn to the left, B would be on the point of receiving
the double current just leaving C.
The armature thus receives 12 impulses in each revolution.
There is no dead
point, because, even during the brief interval which occurs, just before a magnet
changes its polarity a path is open to the current through the other two coils, thus
tending to produce rotary motion.
Having thus described the principle of my invention as adapted to the employ-
ment of three armature magnets and four field pole pieces, it will readily be
understood that the same principle is equally applicable to other numbers of
armature and field magnets in which the armature has one more or one less coil
than the number of pole pieces of the field magnets. In all cases the number of
commutator brushes employed corresponds with the number of pole pieces of the
field magnets.
Fig 7 represents a combination of five armature magnets with four pole pieces.
In this case instead of the armature coils receiving four times in each revolution a
double current, each of the coils remains four times in a revolution unexcited during
a twentieth of the revolution. Referring to diagram No 1 of this Fig, the ends of
the armature coils being fixed as before, the outer ones to segments a¹, b', c¹, d
and el, and the inner ones to segments a, b, c, d and e, and calling the magnets
belonging to the respective segments A, B, C, D and E, it will be seen that magnet A,
becomes negative, magnet B, positive, magnet C, negative, magnet D, positive, and

page_text: magnet E is at rest, being unexcited by any current. The commutator having
turned one-twentieth of a revolution, as shown in diagram N° 2, magnet E, becomes
positive, magnet A, negative, magnet B, positive, magnet C, negative, and magnet
D is at rest. The contacts of the brushes with the commutator are represented by
the vertical lines 1, 2, 3 and 4. In the case where the number of armature coils is
greater by one than the number of field magnet poles, there is an angular displace
ment or shifting round the axis of the two series of segments of the commutator, so
that the segments belonging to the same coil are moved away from each other,
while in cases where the armature coils are fewer by one than the field poles, the
displacement takes place in the opposite direction; taking as the starting point in
both cases such a position that the end of a segment in one series is in a line with
the commencement of a segment in the other series. In the former case the
segments remain intact and their number in each series is only of the number of
armature coils employed, while in the second case the segments are divided and
connected in the manner shown in Fig 5. There are in consequence, in the latter
case, apparently double the number of segments in each series, though in reality,
taking into consideration how they are connected, their number is the same as that
of the coils.
The amount of angular displacement of the segments necessarily depends on the
numbers employed. In the case of four field poles and three armature coils the
difference between one-third and one-fourth of the whole length is one-twelfth,
which is the amount of displacement, and as there are six segments in each series
the commencement of a segment in one series is just opposite the middle of a
segment in the other series, as shown in Figs 5 and 6.
Fig 8 refers to a combination of five armature coils with six field poles. In
diagram No 1 of this Fig, calling the magnets connected with the segments
a, a, b, b, c, c, d, d¹ and e, e¹ respectively A, B, C, D and E, the magnet A receives a
double current and is negative, B is positive, C, negative, D, negative, and E
positive. Shifting the commutator one-thirtieth of a revolution as shown in
diagram N° 2, magnet A is negative, B is positive and receives a double current,
C is negative, D positive, and E positive. The contacts of the brushes with the
commutator are represented by the vertical lines 1, 2, 3, 4, 5 and 6.
Fig 9 refers to seven armature coils and eight field poles. The angular displace-
ment is one fifty-sixth of the whole length. Calling the magnets connected with
the segments a, a, b, b', c, c, d, d, e, e', f, f¹ and g, g', respectively A, B, C, D, E, F
and G, the magnet A has a double current and is negative, B is positive, C negative,
D positive, Ẹ positive, F negative, and G positive. It is clear that after the
commutator has turned one-eighth of a revolution, all the seven coils will have
received in their turn the double current, and all the coils will now be of the
opposite polarity to what they were at the commencement. The contacts of the
brushes with the commutator are represented by the vertical lines 1, 2, 3, 4, 5, 6, 7
and 8.
It will be readily understood that by doubling the original number of the
armature coils, the segments in the commutator, the pole pieces of the field magnets,
and the commutator brushes, the angular displacement of the segments of the
commutator remaining the same, the action and changes above described will take
place simultaneously in the two halves of the armature, thereby forming a double
machine in each half of which a similar action will take place to that which occurs
in the arrangements above described. Or instead of doubling the armature coils,
segments, pole pieces, and brushes, any other multiple of the original number may
be employed, and a similar action will result in each of the parts or sections as
originally formed and heretofore described.
I wish it to be understood that I do not confine myself to any particular form of
field magnets. They may be of the shape shown in Fig 2, or of a ring form as
shown in Fig 10, or they may be straight magnets with polar extensions as shown
in Fig 11, or of any other suitable form, and they may be connected up either in
series or in multiple arc.
:

page_text: It will also be understood that the magnets of the revolving armature instead of
being of T form as shown, may be of any other suitable form, the ends of the wires
of the armature coils being connected to the commutator in the manner described.
As a motor, by reversing the action, becomes a generating machine, or vice versa,
and as I do not confine myself to any particular form of magnets and coils, it will
be readily seen that the commutator and the arrangement of brushes as described
are equally applicable to generating machines in which the number of armature
coils is either one more, or one less than the number of field pole pieces.
Having now described the nature of my invention and the manner of carrying
the same into effect what I claim is :-
1st The improved electro-motor in which there are as many contact brushes
employed as there are pole pieces in the field magnets, the number of armature coils
being one less or one more than the number of pole pieces of the field magnets, in
combination with a commutator, the segments of which are divided into two series,
suitably situated in relation to each other and connected, substantially as described
and shown in the drawings.
2nd The improved commutator in which the segments are divided into two
series suitably situated in relation to each other and connected, substantially as
described and shown in the drawings.
In witness whereof, I, the said Moritz Immisch have hereunto set my hand and
seal, this 22nd day of March in the year of our Lord One thousand eight
hundred and eighty-three.
MORITZ IMMISCH (L.S.)