Improvements in and relating to Electro Motors for Driving Centrifugal Pumps.
Year: 1897

page_text: Date of Application, 23rd Sept., 1897
Complete Specification Left, 30th Mar., 1898-Accepted, 18th June,
3.
1898
IROYIDIUNAL DROPICATION,
Improvements in and relating to Electro Motors for Driving
Centrifugal Pumps.
A communication from the SOCIETE EMILE SALMSON ET CIE, of Paris, in the
Republic of France.
I, ARTHUR FREEMORE SPOONER, of 323, High Holborn, in the County of London,
Chartered Patent Agent, do hereby declare the nature of this invention to be
as follows:
This invention relates to centrifugal pumps of that kind wherein the pump and
a dynamo machine having a common axis are combined and mounted upon the
same bed or base plate.
Apparatus of this class has been in use for a considerable time, and dynamos
of all types have been employed for the said purpose, such as continuous current
machines, motors with rotating fields, and synchronous motors with alternating
currents. Good results have been obtained by their use when the centrifugal
pumps are only employed to raise water to a certain predetermined height, and
are consequently only required to rotate at a uniform velocity. This is not the
case, however, when as in most instances the height of the lift varies.
The use of the above machines must, therefore, be definitely rejected in cases
wherein it is desired to be able to vary, without affecting to any appreciable extent
the efficiency of the system, the speed of the pump in the relative proportion of
1 to 3, and that in the most gradual manner possible.
Continuous current machines are found to afford this advantage, that, for a
similar voltage, the velocity which they develop, is inversely proportionate to the
intensity of their magnetic field, and is consequently governed by their exciting
current, which can be caused to vary at will.
The problem to be solved in the present instance is to construct a continuous
current dynamo in which the variations of its exciting current will have no in-
fluence upon the proper maintenance of its brushes, which is not the case with the
machines usually employed; and it is the arrangements which admit of this result
being obtained and the adaptation thereof to machines destined to drive centrifugal
pumps which forms the object of the present invention.
Firstly As regards the special arrangement required in order to admit of a
continuous current dynamo working under favourable conditions, whatever may
be the intensity of its field of induction, all that is necessary is that its reaction of
induction be rendered nil by artificial means, and this result is obtained in the
following manner: In the case, say, of a dynamo of what is known as
"Manchester" type which has an armature of the Gramme-Paccinotti description
and the inductors, properly so called, of which, consist of two bobbins and are
grouped either in series, or in shunt.
the
The novel features characterising this machine, according to the present inven-
tion, consists in the provision of a number of recesses or holes which are formed in
1

page_text: its polar extensions or surfaces, preferably in such a manner that the surface of
the pole pieces will be as little reduced thereby as possible. In each of these
apertures or holes is fitted a bobbin so as to surround the pole pieces of the
machine..
I
".
In all cases these bobbins should be so grouped that their magnetic force
will all be in the same direction. The magnetic force developed by the lower and
upper bobbins will thus be in opposition and will, consequently, determine two
points upon the line of contact of the brushes.
These bobbins should, moreover, always be connected in series with the armature,
and their number of windings should be so calculated that the consequent poles
developed by them may have the same intensity as those developed by the armature.
Finally these bobbins should be so grouped with the armature that the poles will
be two to two in opposition.
Under these conditions, whatever may be the intensity of the current passing
through the armature, the latter cannot develop any flux, inasmuch as the bobbins
will develop in every case a magnetic force equal to, and of a contrary denomination
to, the former.
"Thus there will be no reaction of the, induction, the action of the brushes will
remain invariable, and if the ring be sufficiently divided, its rotation will produce
o sparking at the said brushes even when the flux engendered by the inductors
is nil.
no
*****
The larger the number of apertures or holes, and of contained bobbins that are
provided the better will be the results obtained.
It is to be remarked moreover that the expenditure of energy effected in these
bobbins will be largely compensated for by the diminution of the expenditure of
energy necessitated for the excitation of the dynamo. It would be easy, moreover,
to demonstrate that the benefit is considerable.
t
From the above it will be readily understood that the velocity of rotation of
this machine may be varied within the largest limits, whilst at the same time
maintaining a constant voltage between the brushes, by causing a variation in
the intensity of the current thrown into the inductors.
If these latter be mounted in shunt between the brushes, a rheostat with a
variable resistance should be included in their circuit; if they are mounted in
series, a shunt having a resistance, also variable at will, should be mounted
in shunt with them.
In the above description it is supposed, as already mentioned, that a machine
of the "Manchester type, with a Gramme Pacinotti ring, is employed. It
is to be clearly understood, however, that this machine is simply mentioned by
way of example, and that the dynamo machine, and the winding of the armature,
may be of any other suitable system, but that in all cases a special winding
mounted in the recesses or holes provided in the polar extensions or surfaces of
the inductors, and mounted in series with the armature and serving to engender
magnetic forces equal, and of contrary denomination to those developed by the
armature must be provided.
Secondly: As regards the application to centrifugal pumps, a centrifugal pump
of the "Salmson" type, having a horizontal axis coupled directly to a dynamo
such as that herein before described, and mounted upon the same bed or base
plate, may be employed. It will be readily understood, however, that this arrange-
ment is applicable to any other type of centrifugal pump with either a horizontal
or vertical axis.
In order to render the system as complete as possible, moreover, suitable means
are provided for automatically ensuring the constancy of the discharge of the
pump, in spite of any variations in the height of lift, by simply supposing that the
voltage maintained between the brushes of the dynamo will be constant."
These means are as follows:
Supposing, by way of example, that the inductors be mounted in shunt, a
rheostat will have to be included in their circuit Tf
on
the
11

page_text: machine revolves too rapidly, it will be necessary to increase the field, and for that
purpose to diminish the resistance of the rheostat, if, on the other hand, the
machine does not rotate fast enough it will be required on the contrary to diminish
the field, and with that object to increase the rheostat.
In an installation of this description there will naturally be always a plentiful
supply of water to be disposed of, and it will therefore be found convenient to
employ a liquid rheostat constructed in the following manner.
A suitable tank or receptacle is arranged to contain two metal plates to which
are connected the conductors and water. The resistance of this rheostat can be
caused to vary by increasing or diminishing the level of the said water in the tank
or receptacle the resistance being diminished by raising the water level, and
augmented by lowering it. For the above purpose a suitable outlet or adjutage
is located in the tank or receptacle at a certain elevation and allows the water
to escape constantly, another adjutage or inlet discharging into the upper part
of the tank and having an automatically governed outlet being likewise provided.
If the machine rotates too rapidly, it is required to raise the level of the water
in the tank or receptacle and for that purpose to increase the discharge from the
inlet thereto. If on the contrary the machine does not rotate fast enough, all
that is required is to diminish the discharge from the latter and the tank or
receptacle will empty itself through the lower adjutage or outlet.
For regulating the discharge from the water inlet two small pipes or tubes are
arranged co-axially in the interior of a tube forming part of the flowing
back or return pipe one of which tubes has an aperture in the form of
a nozzle or tuyere, and the other of conical or funnel shape, the said apertures
facing one another, and the pipes communicating with the two bottoms of a
cylinder of two diameters enclosing two coupled differential pistons. The pipe
with the conical or funnel shaped mouth or aperture being connected with the
smaller and that with the nozzle with the larger end of the cylinder respectively.
The water flows through the flow back or return pipe in a direction towards the
conical or funnel-shaped mouth or aperture.
It will be readily understood that should the speed of the flow of water
become greatly reduced or practically nil, the pressure per square centimetre will
become equal upon the faces of both the above mentioned pistons, and the system
will be relieved.
If the speed of the flow of water, however, be not greatly reduced or nil, the
pressure per square centimetre on the face of the smaller piston will become
greater than that on the larger piston.
At a certain predetermined velocity of the flow of water, moreover,
will remain in a state of equilibrium.
the system
In fact for all decrease in velocity the pistons will be raised, and for all increase
in velocity they will be lowered. .
Advantage is taken of these displacements of the pistons to raise or lower a
clack valve which will uncover or close the orifice of a pipe connected with the
upper adjutage or inlet.
It will be seen therefore, that, if the speed of the pump be too low, the said clack
valve will be closed and there will be no discharge from the said upper adjutage
or inlet and the tank or receptacle will empty itself gradually through the lower
outlet or adjutage, and the speed of the dynamo be consequently increased.
If the velocity of the water on the contrary be too great, the said clack valve
will be moved or opened so as to uncover the orifice of the pipe communicating
with the upper adjutage or inlet, and, if the latter be arranged to be of superior
capacity to that of the lower outlet or adjutage (a condition easily secured) the
tank or receptacle will be gradually refilled and the speed of the machine
diminished.
In a case where the inductors of the machine are mounted in series with the
armature, the rheostat formed by the above mentioned tank or receptacle. should
be mounted in shunt between their extremities, and in this instance in order to

page_text: increase the speed of the machine it will be necessary to raise the level of the water
and reciprocally in a manner exactly the contrary to that which has been just
described. It is sufficient for this purpose to reverse the play of the clack valve
governing the mouth or aperture of the upper adjutage or inlet.
D
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29 , 1
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1
1007
Centrifugal Pumps.
A communication from the SOCIETE EMILE SALMSON ET CIE, of Paris, in the
Republic of France.
I, ARTHUR FREEMORE SPOONER, of 323, High Holborn, in the County of London,
Chartered Patent Agent, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
__
This invention relates to electro-motors intended more especially for driving
centrifugal pumps. It refers particularly to that class of apparatus wherein the
armature of the motor and the pump have a common axis, the two machines being
combined and mounted upon the same bed or base plate.
Apparatus of this class has been in use for a considerable time, and dynamos or
motors of all types have been employed for that purpose, such as continuous
current machines, motors with rotating fields, and synchronous motors with alter-
nating currents. Good results have been obtained by the use thereof when the
pump has been required only to raise water to a certain predetermined height and
consequently only to rotate at a uniform velocity. This is not the case, however,
when the height of the lift varies, as it does in many instances.
The use of the above machines must, therefore, be rejected in cases wherein
it is desired to be able to vary, without affecting to any appreciable extent the
efficiency of the system, the speed of the pump in the relative proportion for
example of one to three, and that as gradually as possible.
Continuous current machines afford the advantage that, for a given voltage,
the speed that they develop is inversely proportional to the intensity of their
magnetic field, and such speed is consequently governed by their exciting current,
which latter can be caused to vary at will.
The problem to be solved in the present instance is to construct a continuous
current machine in which the variations of its excitation will have no influence
on the position of its brushes, which is not the case with the machines usually
employed and it is the arrangements which admit of this result being obtained,
and the adaptation thereof to machines destined to drive centrifugal pumps which
form the object of the present invention.
In the accompanying drawings,
Figure 1 is an end elevation of a dynamo or motor constructed in accordance
with my invention.
Figure 2 is a plan view showing the two machines with a common axis and
mounted upon the same bed or base plate and
Figure 3 is a liquid rheostat hereinafter more fully referred to.
Firstly; As regards the special arrangement required in order to admit of a
continuous current machine working under favourable conditions, whatever may
be the intensity of its field of induction, all that is necessary is that its reaction
of its armature be rendered nil by artificial means, and this result is obtained
in the following manner; In the case of a machine, for example, of the

page_text: "Manchester" type such as that shown in Figure 1, which has an armature A
of the Gramme-Paccinotti type a collector c and brushes b, b and the inductors B, B
which consist of two bobbins and are grouped either in series or in shunt.
The novel features characterizing this machine according to the present inven-
tion, consist in the provision of a number of recesses or holes E, E, which are
formed in its pole pieces preferably in such a manner that the surface of such
pole pieces will be as little reduced thereby as possible. In each of these recesses
or holes is a winding or bobbin F so as to surround the pole pieces of the machine.
In all cases these windings or bobbins F are so grouped that their magnetizing
forces will all be in the same direction. The magnetizing forces developed by
the lower and upper windings or bobbins will thus be in opposition, and will,
consequently, determine two poles upon the line of contact of the brushes.
These windings or bobbins F should, moreover, always be connected in series
with the armature, and their number of windings should be so calculated that
the consequent poles developed by them may have the same intensity as those
developed by the armature. Finally these windings or bobbins should be so
grouped with the armature that the poles will be two to two in opposition.
Under these conditions, whatever may be the intensity of the current passing
through the armature, the latter cannot develop any magnetization inasmuch as
the bobbins F will develop in every case a magnetizing force equal to, and of a
contrary denomination to, the former.
Thus there will be no reaction of its armature, the position of the brushes will
remain invariable, and if the armature be sufficiently divided, its rotation will
produce no sparking at the said brushes even when the flow generated by the
inductors is nil.
The greater the number of recesses or holes E, and of contained windings or
bobbins F that are provided, the better will be the result obtained.
It is to be remarked, moreover, that the expenditure of energy effected in these
bobbins will be largely compensated for by the diminution of the expenditure of
energy necessitated for the excitation of the machine. It would be easy, moreover,
to demonstrate that the benefit is considerable.
From the above it will be readily understood that the speed of rotation of this
machine may be varied within the largest limits, whilst at the same time maintain-
ing a constant voltage between the brushes, by causing a variation in the intensity
of the current thrown into the inductors B.
If these latter be mounted in shunt between the brushes, a rheostat with a
variable resistance should be included in their circuit; if they are mounted in
series, a shunt having a resistance, also variable at will, should be mounted in
shunt with them.
In the above description it is supposed, as already mentioned, that a machine of
the "Manchester" type, with a Gramme-Paccinotti ring is employed. It is to
be clearly understood, however, that this machine is simply mentioned by way of
example, and that the dynamo machine or motor, and the winding of the armature,
may be of any other suitable character But that in all cases a special winding
mounted in the recesses or holes E provided in the pole pieces or surfaces of the
inductors, and mounted in series with the armature, and serving to generate
magnetizing forces equal and of contrary denomination to those developed by the
armature, must be provided.
Secondly: As regards the application to centrifugal pumps. A. centrifugal
19
pump of the Salmson type having a horizontal axis coupled directly to a
dynamo or motor such as that herein before described, and mounted upon the same
bed or base plate may be employed as shown in Figure 2. It will be readily
understood, however, that this arrangement is applicable to any other type of
centrifugal pump with either a horizontal or vertical axis.
In order to render the system as complete as possible moreover, suitable means
are provided for automatically ensuring the constancy of the discharge of the
pump, notwithstanding variations in the height of lift, and assuming that the

page_text: voltage maintained between the brushes of the machine will be constant. These
means are as follows:
}
Supposing, by way of example, that the inductors B be mounted in shunt,
arheostat will have to be included in their circuit. If on the one hand the machine
revolves too rapidly, it will be necessary to increase the field and for that purpose
to diminish the resistance of the rheostat, if, on the other hand the machine
does not rotate fast enough it will be required on the contrary to diminish the field,
and with that object to increase the resistance of the rheostat.
In an installation of this description there will naturally be always a plentiful
supply of water to be disposed of, and it will therefore be found convenient to
employ a liquid rheostat, such as that illustrated in Figure 3, which is constructed
in the following manner:
..A suitable tank or receptacle Ris arranged to contain two metal plates a,
m to which are connected the conductors, and y, y. The receptacle R is
intended to contain water. The resistance of this rheostat can be caused to vary
by increasing or diminishing the level of the said water in the tank or receptacle;
the resistance being diminished by raising the water level, and augmented by
lowering it. For this purpose a suitable outlet or ajutage M is located in the
tank or receptacle at a certain elevation and allows the water to escape constantly,
another ajutage or inlet N discharging into the upper part of the tank, and having
an automatic governing device, being likewise provided.
If the machine rotates too rapidly, it is required to raise the level of the water
in the tank or receptacle R and for that purpose to increase the discharge from
the inlet N thereto. If on the contrary the machine does not rotate fast enough,
all that is required is to diminish the discharge from the latter, and the tank or
receptacle will empty itself through the lower ajutage or outlet M.
For regulating the discharge from the water inlet N two small pipes or tubes II
and I are arranged co-axially in the interior of a tube K forming part of the
flowing back or return pipe. The lower tube H, or one of these tubes, has an
aperture in the form of a nozzle or tuyere, and the upper tube I, or other of the
said tubes, has an aperture of a conical or funnel shape, the said apertures facing
one another as shown in the drawing, and the pipes communicating with a cylinder
formed in two diameters and enclosing two coupled differential pistons P and Q;
the pipe with the conical or funnel shaped mouth or aperture I being connected
with the smaller, and that with the nozzle H, with the larger end of the cylinder
respectively. The water flows through the back or return pipe in a direction
towards the conical or funnel-shaped mouth or aperture that is to say in the direction
of the arrow shown in the drawing.
It will be readily understood that should the speed of the flow of water become
greatly reduced or practically nil, the pressure per square inch will become equal
upon the faces of both the above mentioned pistons, and the system will be relieved.
If the speed of the flow of water, however, be not greatly reduced or nil, the pressure
per square inch on the face of the smaller piston Q will become greater than that
on the larger piston P. At a certain predetermined velocity of the flow of water,
moreover, the system will remain in a state of equilibrium. In fact for all decrease
in velocity the pistons will be raised, and for all increase in velocity they will be
lowered. Advantage is taken of these displacements of the pistons P and Q to raise
or lower a plug or valve U which will open or close the orifice of a pipe connected
with the upper ajutage or inlet N. It will be seen therefore, that, if the speed
of the pump be too low the said plug or valve U will be closed, and there will
be no discharge from the said upper ajutage or inlet N and the tank or receptacle R
will empty itself gradually through the lower outlet or ajutage M and the speed
of the machine be consequently increased. If the velocity of the water on the con-
trary be too great, the said plug or valve U will be moved or opened so as to uncover
the orifice of the pipe communicating with the upper ajutage or inlet N, and, if
the latter be arranged to be of superior capacity to that of the lower outlet or

page_text: ajutage M (a condition easily secured) the tank or receptacle will be gradually
refilled and the speed of the machine diminished.
In a case where the inductors of the machine are mounted in series with the
armature, the rheostat formed by the above mentioned tank or receptacle R should
be mounted in shunt between their extremities, and in this instance in order to
increase the speed of the machine, it will be necessary to raise the level of the
water and reciprocally in a manner exactly the contrary to that which has just
been described. It is sufficient for this purpose to reverse the play of the valve U
governing the mouth or aperture of the upper ajutage or inlet N.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. The combination of a centrifugal pump and of a continuous current dynamo
machine or electro-motor having the required number of windings or bobbins
arranged in recesses or holes formed in the pole pieces of the machine, connected
in series with the armature of the machine in such a manner as to destroy its
reaction of its armature, and distinct from those intended to produce the magnetic
field, whereby the speed of the machine is rendered capable of variation within
wide limits whilst maintaining a constant voltage, by only varying its excitation.
2. The employment of a liquid rheostat the variations of resistance of which are
determined by the variations in the level of the water in a receptacle, the height
of which level is automatically regulated by the variations in the speed of the
outflow of water in the conduit of the pump, by means of the intermediary
apparatus hereinbefore described.
3. The improved rheostat constructed substantially as described with reference
to Figure.3 of the accompanying drawing, and operating in the manner and for
the purpose herein before specified.
4. The combined dynamo machine or electro motor and centrifugal pump sub-
stantially as described and as illustrated in Figure 2 of the accompanying drawing.
Dated this 30th day of March 1898
A, F. SPOONER..