Improvements in Electrical Motor Generators.
Year: 1897

page_text: Date of Application, 24th Mar., 1897
Complete Specification Left, 23rd Dec., 1897-Accepted, 19th Feb., 1898.
Improvements in Electrical Motor Generators.
We, SIEMENS BROTHERS & Co. LIMITED, of 12, Queen Anne's Gate, Westminster,
in the County of London, and HENRY COOK LEAKE, of 151, Church Lane, Charlton,
in the County of Kent, Electrical Engineers, do hereby declare the nature of this
invention to be as follows:
This invention relates to electrical motor generators so constructed and arranged
that the currents generated by them and the electro motive force of these currents
can be readily varied.
For this purpose we fix on one shaft two armature cores, the one, which may be
termed the doubly wound core, being wound with both motor and generator wind-
ings; and the other, which may be termed the singly wound core, being wound
with either motor or generator windings, but not with both. Each of these cores
is mounted to revolve in a separate polar field, but the windings on the cores of
both the field magnets are so proportioned that the ratio between the ampère turns
on the two cores is constant when the existing current is varied. The windings
on the cores may be connected in series or in parallel or one winding may be wound
continuously round both cores. These coils may be in shunt from either the motor
or the generator conductors. The two magnets mây be made of such different
forms or different materials that, while the core of the one magnetically saturated,
that of the other is not saturated. This may be done by making the core of the
saturated magnet of considerably smaller sectional area than the surface of its
pole piece and by suitably proportioning the air gaps. Or the saturated magnet
may be made of cast iron, the other being of cast steel or malleable iron. For
regulating the machine, we employ a rheostat of any suitable known kind by which
the current in the magnet coils can be varied. Or we may make these coils in
sections, a greater or less number of which may be put in circuit, or the cores may
be compound wound, the series winding being arranged to aid or oppose the shunt
winding as may be desired.
Instead of employing two separate magnets as above described, a single magnet
core may be employed having two pole pieces one presented to each of the armatures.
While the main core is wound with a suitable number of ampère turns, which may
be connected in shunt to either the motor or generator conductors, the pole pieces
are wound with regulating coils in opposite directions, these coils being connected
in series with either the generator or motor conductors, so that any change of the
exciting current in the regulating coils strengthens the one polar field, relatively
to the other.
The effect of magnets constructed and arranged in any of the ways above described
is that a change of the exciting current increases or lessens the electro motive force
of the generated current, so as to suit the electro-motive force to the load, such
change being effected with or without a variation in the speed of revolution of
the armature.
Dated this 04th dow of 1am 1007
ABEL & IMRAY,
Agents for the Applicants.

page_text: Improvements in Electrical Motor Generators.
We, SIEMENS BROTHERS & CO. LIMITED, of 12, Queen Anne's Gate, Westminster,
in the County of London, and HENRY COOK LEAKE, of 141, Church Lane, Charlton,
in the County of Kent, Electrical Engineers, do hereby declare the nature of this
invention 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 electrical motor generators so constructed and arranged
that the currents generated by them and the electro motive force of these currents
can be readily varied."
For this purpose we fix on one shaft two armature cores, the one, which may be
termed the doubly wound core, being wound with both motor and generator wind-
ings; and the other, which may be termed the singly wound core, being wound
with either motor or generator windings, but not with both. Each of these cores is
mounted to revolve in a separate polar field, but the windings on the cores of both
the field magnets are so arranged that the ratio between the ampère turns on the
two cores is constant when the exciting current is varied. The windings on the
magnet cores may be connected in series or in parallel with each other or one wind-
ing may be wound continuously round both cores. These coils may be in shunt
from either the motor or the generator conductors. The two magnets may be made
of such different forms or different materials that, while the core
the one is magnetically saturated; that of the other is not saturated.
This may be done by suitably proportioning the lengths and cross sections of the
air portions and the metallic portions of the magnetic circuits, so that the resistance
of the one core to its magnetic flux is large relatively to the resistance of the other
core to its magnetic flux. Or the saturated magnet may be made of cast iron, the
other being of cast steel or malleable iron. For regulating the machine, we employ
a rheostat of any suitable known kind by which the current in the magnet coils
can be varied. Or the cores may be compound wound, the series winding being
arranged to aid or oppose the shunt winding as may be desired.
of
Instead of employing two separate magnets as above described, a single magnet
core may be employed having two pole pieces one presented to each of the
armatures. While the main core is wound with a suitable number of ampère
turns, which may be connected in shunt to either the motor or generator con-
ductors, the pole pieces are wound with regulating coils to give opposite polarity,
these coils being connected with either the generator or motor conductors, so that
any change of the exciting current in. the regulating coils strengthens the one
polar field, relatively to the other.
The effect of magnets constructed and arranged in any of the ways above described
is that a change of the exciting current increases or lessens the electro motive force
of the generated current, so as to suit the electro motive force to the load, such
change being effected with or without a variation in the speed of revolution of the
armature.
motor
Figure 1 of the accompanying drawings diagrammatically illustrates a
generator having the cores of the field magnets for both armatures wound with
one coil, these cores themselves differing in respect of saturation or magnetic
character. Figure 2 illustrates diagrammatically the modification in which while
the pole pieces for the two armatures have a common main core with its winding
the one
each of these pole pieces has a winding of its own as shewn in Figure
winding giving a polarity opposite to that given by the other.
In both Figures 1 and 2, A is the armature with double winding the one wind-
ing a connected to the commutator a¹ which supplies the leads a a³, the other

page_text: winding b is continuous with that of the single wound armature B and is con-
nected to the commutator 6', which is supplied by the leads 68 63. In Figure 1
there are two field magnets C D one for each armature; but both have a common
winding W in shunt from the leads ba 63. In Figure 2 there is a single field
magnet with a common core and two pole pieces C, D. The common core is
wound with a winding W in shunt from the leads 63 63. The pole pieces C and D
have windings c and d which are also in shunt from the leads 62 63 and are wound
oppositely as shewn in Figure 3. A rheostat R is in Figure 1 interposed between
the field magnet winding W and the lead 62 but in Figure 2, while the winding W
is in direct connection with the leads b2 63, the rheostat R is interposed between
the windings c and d and the lead 62. Although the windings of the field magnets
are shewn in the drawings as being in shunt from the leads for the motor currents,
they might be in shunt from the leads for the generated currents.
By double winding the magnet cores C, D, Figure 1, the one winding in shunt
and the other in series with the main leads, or by connecting the coils c d of the
pole pieces (Figure 2) in series with the main leads, the rheostat R may be dis-
pensed with, the machine being in that case self regulating.
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 a motor generator having a single and a double wound armature on the
same shaft, in combination with each of these armatures a field magnet, both mag-
nets having their cores double wound, the one winding in shunt and the other
in series with the main leads, or having a single winding in that case governed by
a rheostat but the one magnet differing from the other in form or material so
as to differ from it in respect of saturation, substantially as and for the purpose
set forth.
2. In a motor generator of the kind above referred to, in combination with the
two armatures a single field magnet with one winding and with two pole pieces
having opposite windings in series with the main leads or in shunt with them and
in that case governed by a rheostat, substantially as and for the purpose set forth.
Dated this 23rd day of December 1897.
ABEL & IMRAY,
Agents for the Applicants.