IMPROVEMENTS IN SELF REGULATING ELECTRO-MOTORS AND DYNAMO-ELECTRIC GENERATORS
Year: 1884

page_text: "
We, WILLIAM MORRIS MORDEY, of 144 Disraeli Road Putney, in the County of
Surrey, Electrician, and CHARLES WATSON of 20 Upper Parkfields, Putney in the
County of Surrey, Electrician, do hereby declare the nature of said invention for
IMPROVEMENTS IN SELF REGULATING ELECTRO-MOTORS AND DYNAMO-ELECTRIC
GENERATORS" to be as follows:-
This invention has for its objects improvements in the construction of electro-
motors and dynamo-electric generators, and has reference particularly to the self
regulating power of the same.
In electro-motors, as hitherto usually constructed the speed has varied greatly
with alterations in the work imposed on them. One of the objects of this
invention is to obtain a constant or nearly constant speed of rotation under
varying conditions of load.
In dynamo-electric generators, as hitherto constructed, whether worked on the
series, shunt, compound series and shunt, or separately excited principle, it has
always hitherto been necessary to maintain a steady and uniform rate of speed in
order to obtain the required regularity of electrical conditions in the external
circuit of the dynamo. A further object of our invention is, with dynamo-electric
generators, to obtain constant or nearly constant electromotive force, or potential
difference, and constant current, or either or both, at irregular speeds of rotation.
Qur improved method of governing electro-motors is applicable to all ordinary
types of electromotors, whether they are merely dynamo-machines working with
inverted action or otherwise.
According to our invention we wind the field-magnets of the motor with two
wires, wound or connected in such a manner that the current passing through the
wire of one coil assists the current passing through the wire of the other coil. We
also wind the armature with two wires or circuits, not connected with one another
in any way, but joined up to form two separato and distinct circuits, and oach
provided with a separate and distinct commutator or collector. One of these
armature circuits occupies relatively only a small portion of the available space,
and in some cases consists of merely a very few convolutions of wire.
This additional armature circuit is connected by means of its commutator and
contact brushes or springs or their equivalents, directly to the ends of one of the
field-magnet circuits, which for convenience may be called the additional field
circuit; the other field-magnet circuit being .connected with the mains or other
source of electric supply in the usual way, either in series with the main armature
circuity or as a shunt across it.
In the case of a magneto-electric motor, that is, one in which the field-magnet is
a permanent magnet, we use only one circuit on the field-magnets, viz :-the
additional field-magnet circuit above-mentioned, to which the additional armature

page_text: circuit is connected by means of its commutator or collector, and brushes. By
these arrangements we obtain a constant or nearly constant speed with a varying
load.
In applying our invention to electric-generators we are able to construct
dynamo-machines of any of the above-mentioned types capable of maintaining the
necessary constant or nearly constant external electrical conditions when driven by
steam engines or other motors which from being badly governed, or having varying
loads imposed on them, or from other causes work with irregular speed and are on
that account unsuitable for driving dynamo-machines of the usual construction.
In the case of dynamo-machines according to our invention, we wind an
additional circuit on the armature, as in the case of motors constructed according
to the principle of our invention. This additional armature circuit is of com-
paratively small size and power, and is entirely separate and distinct from the
main armature circuit, and is connected to a separato commutator or collector, on
which press brushes or their equivalents.
On the field-magnets we also wind two separate and distinct circuits; one,
which may be called the main field-magnet circuit, being of the usual description-
that is to say it may be in series with the armature and external circuit, or it may
be a shunt on the armature, or it may be a compound winding consisting of a
combination of shunt and series.
The second circuit (which we call the additional field-magnet circuit) is quite
separate electrically from the main series or shunt circuit, or from the compound
series and shunt circuits as the case may be, and is joined directly to the brushes
of the commutator of the additional armature circuit in such a way that the
current passing through it is in such a direction as to tend to produce a magnetic
polarity opposite to that produced by the main field-magnet circuit.
In the case of separately excited machines, whether of the alternate current or
direct current type, we construct the exciting machine (which is assumed to be
driven by the same engine, as the excited machine, and therefore subject to the
same irregularities of speed) according to the principle of our invention so that the
variations in speed do not produce variations in the external circuit of the excited
machine. That is to say we construct the excitor, according to our invention, to
produce a decreasing current with an increasing speed and vice versa.
We are aware that attempts have been made to automatically control the output
of dynamo-machines by the use of arrangements which usually act on the
principle of changing an electrical resistance usually placed either in the field-
magnet circuit, or as a shunt across it.
We are also aware that the control has sometimes been made by an automatic
adjustment of the brushes or commutator with respect to the armaturo.
These various contrivances all require a change of condition to set them in
operation, that is to say, the irregularity which it is sought to prevent must to
some extent occur before it can be corrected.
Now in this our invention, as regards dynamo-machines, our object is to effect
the regulation simultaneously with the change of speed, so that no change occurs
in the electrical conditions of the external circuit, or no change is produced by the
alteration of the speed.
It will be understood that in the case of compound-wound machines the usual
alterations of current or potential may be produced by the alteration of the external
circuits of such machines in the usual way, but according to our invention such
machines are unaffected by variations of speed.
J

page_text: COMPLETE SPECIFICATION.
We, WILLIAM MORRIS MORDEY of 144 Disraeli Road, Putney, in the County of
Surrey, Electrician, and CHARLES WATSON of 20 Upper Parkfields in the County
of Surrey, Electrician do hereby declare the nature of our said' invention for
"IMPROVEMENTS IN SELF-REGULATING ELECTRO-MOTORS AND DYNAMO-ELECTRIC
GENERATORS" and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement :-
In electro-motors as hitherto usually constructed, the speed has varied greatly
with alterations in the work imposed on them. The object of this invention is to
obtain a constant or nearly constant speed of rotation under varying conditions
of load.
Our improved method of governing electro-motors is applicable to all ordinary
types of electromotors whatever the shape or design of the armature or field magnets
may be and whether they be merely dynamo machines working with inverted
action or otherwise.
According to our invention we wind the field magnets with two separate wires
or windings, wound or connected in such a manner that the current traversing one
coil or winding strengthens the magnetisms of the field magnets produced by the
current passing thro' the other coil or winding. That is to say the two coils or
sets of windings act in assistance of each other. The action is not a differential
one.
We do not confine ourselves to any particular arrangement of the windings on
the field magnets. They may be placed over one another, or side by sido; or when
one polepiece has (say) two cores or limbs springing from it, one winding may be
on one limb, and the other winding on the other limb. The first named arrange-
ment that of placing one winding over the other, is however that which we
prefer.
We also wind the armature with two windings, not connected with one another
in any way; but joined up to form two separate and distinct armature circuits,
and each provided with a separate and distinct commutator or collector.
The principal armature winding (which we call the main or motor armature
circuit) is by its commutator or collector, and brushes or their equivalents, con-
nected with the mains or other source of electrical supply in the usual way; and
to the same source is also connected one of the field windings above mentioned.
This for convenience we may call the main field circuit. The motor armature
circuit and the main field circuit may be connected with the mains or other sup-
plying conductors in any suitable way, either in series with one another, or in
parallel circuit with one another, or in a combination of the series and parallel
principles. For instance a portion of the main field winding may be traversed by
the current which flows through the armature, while the remainder of the main
field winding may be connected as a shunt on the terminals or on the armature;
but in any case it must be understood that this main field winding is in all its

page_text: parts a magnetising one, and does not in any part exert a demagnetising or
weakening influence, and that the energising of the field magnets is only in part
due to it. The other armature winding, which we call the additional armature
circuit, usually occupies relatively only a small portion of the available space, and
in some cases consists of only a very few convolutions of wire. This additional
armature circuit is connected by means of its commutator or collector, and brushes
or their equivalents, directly to the ends of a separate field magnet circuit which
we call the additional field circuit.
In the case of magneto-electric motors, that is, those in which the field magnets
consists wholly or partly of what are known as permanent magnets, we use only
one winding on the fields, to which the additional armature winding is connected,
the main or motor armature circuit being fed from the source of supply as in the
cases already mentioned.
The regulating effect of our improvement will be understood from the following
general description, which applies in principle to all cases of ordinary working and
connection. Thus whether the motor be connected in series or parallel, and
whether the conditions of supply are those of constant current or constant
difference of potential. Rotation of the armature takes place when current from
the mains, or other feeders of the motor, passes through the main or motor arma-
ture, and through the main field winding. The additional armature winding which
is, as described, on the same core as the main armature winding, acts as a generator
and supplies a current-usually of small quantity and pressure-which traverses
the additional field winding already described, assisting the main field winding to
energise the magnets. If we suppose the case of a motor-let it be a shunt motor
for the sake of illustration-which is required to run at a given speed with any
load within its working range. The armature and fields, and their windings are.
designed accordingly, and when working the field strength is in part due to current
circulating through the shunt winding, and in part to the current generated by
the additional armature. When a portion or the whole of the load is removed the
motor tends to increase in speed, but an increase in the current generated by the
additional armature winding immediately increases the strength of the field, the
opposing. E. M. F of the main motor armature winding rises, less current passes
through it, and thus-as well as by the increase in the generating work done-the
rise in speed is at once checked. Again, if the load is increased the tendency of
the motor is to decrease in speed, but this produces a slight diminution of the
current generated by the additional armature winding; a consequent weakening of
the field; a decreased opposing E. M. F of, and increase of current through, the
main motor armature winding. Thus the fall in speed is at once checked. By
rightly proportioning the two armature windings and the two field windings; or
the relative values of the "permanent" and of the electro-magnetic constituents
of the field as the case may be, we obtain constant or nearly constant speed of
rotation with varying load.
· In our provisional specification we described various modes of applying our
invention in the construction of dynamo electric generators of different kinds but
as we do not now consider such application of our invention advantageous we do
not lay any claim to them.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is
1. In an electro-motor having an armature with two windings one for motive
purposes the use of the second or additional winding for regulating and controlling
the speed of rotation, substantially as herein before described.
2. In an electro-motor the use of field magnets having two windings, one of
:which is traversed by current received from the source of external supply; the
other being traversed by current supplied by an additional armature winding,
substantially as and for the purpose set forth.

page_text: 3. In an electro-motor the use of an armature having two separate windings and
commutators; one for motive purposes in connection with the external source of
current; the other for regulating and controlling purposes connected directly to
an additional field winding substantially as and for the purpose set forth.
4. In an electro-motor the use of field magnets that are partly permanently
magnetic and which are also wound with a conductor in circuit with an additional
armature winding substantially as and for the purpose described.