Improvements in and connected with Dynamo Electric Machines.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in and connected with Dynamo Electric Machines.
We, CHARLES HENRY WADE, of 7 St. James' Square, Chartered Accountant,
JAMES MOORES, and HENRY OLIVER FARRELL, both of 15 Hanging Ditch, Electrical
Engineers, all of Manchester, in the County of Lancaster, do hereby declare the
nature of this invention to be as follows:-
This Invention relates to Dynamo-Electric Machines which are or may be
driven at variable speeds, and its object is to construct and arrange these machines
in such a manner as to produce an output the voltage of which will vary only
within narrow limits notwithstanding variations within wide limits of the speed
of the armature thus permitting the machine to be utilised in train lighting when
driven from the vehicle axle, and under other like conditions.
In carrying out our Invention, we wind the field magnets with two coils, one of
which is the ordinary energising coil. The other coil has preferably fewer ampère
turns, but it is so wound or the current is sent through it in such a direction that it
induces an opposite magnetic effect to that produced by the main coils. We also
divide, without section, the subsidiary coil into a convenient number of sections,
from the end of each of which we bring out a leading wire and attach it to one of
a similar number of contacts on a switch. By means of this switch, we are enabled
to cut off the energising current in the subsidiary winding wholly or partly.
Thus, if the machine is running at low speed, the whole of the subsidiary winding
may be out of circuit. If the speed should increase, the first section of the sub-
sidiary winding is joined in, producing a counter effect to that produced by the
main winding and so preventing any effective increase in the lines of force. If
the speed continues to increase successive sections of the subsidiary coil are joined
in. It will be understood that only the end leading in wire, and one leading in
wire from the sections are joined in with the switch at one time.
We may operate the switch by hand, but prefer to do so automatically by means
of a centrifugal governor, by an electric governor, a tachometer or other similar
device. Our Invention enables us, when the machine is run at a constant speed,
to control the output.
When the whole or a part of the subsidiary coil has been brought into circuit
s and for the purpose herein before described, the principal factor in the main-
enance of the magnetic field is the counter magnetic effect. This counter effect
s however assisted by the increased resistance and may to some extent be regulated
by employing for the subsidiary coil, wire of greater or less resistance.
Dated this 25th day of February A.]). 1897.
W. E. HEYS & SON,
Agents for the Applicants.

page_text: Improvements in and connected with Dynamo Electric Machines.
We, CHARLES HENRY WADE, late of 7 St. James' Square, and now of 37 Cross
Street, Chartered Accountant, JAMES MOORES, and HENRY OLIVER FARRELL, both
of 15 Hanging Ditch, Electrical Engineers, all of Manchester, in the County of
Lancaster, 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 dynamo-electric machines which are or may be driven
at variable speeds, and its object is to so construct and arrange these machines in
such a manner as to produce an output the voltage of which will vary only within
narrow limits notwithstanding variations within wide limits of the speed of the
armature, thus permitting the machine to be utilised in train lighting when driven
from a carriage or other axle, and'under other like conditions.
In a dynamo constructed to embody our improvements the field magnets are
provided with an energising coil and with a subsidiary coil, this latter coil being
wound in such a manner that a current passing through it induces a magnetic.
effect opposed to that induced by the energising coil. This subsidiary coil is
preferably in series with the energising coil and is divided into a convenient
number of sections from the end of each of which a wire is led out to one of a
number of contacts on a switch. By means of this switch any number of the
sections of the subsidiary coil may be put into or out of the circuit.
Thus, if the machine be running at a low or normal speed the whole of the sub-
sidiary coil may be out of the circuit. Should the speed increase the first section
of the subsidiary coil is joined in, and the current passing through it produces a
counter effect to that produced by the main winding and so prevents any effective
increase in the lines of force. Should the speed continue to increase successive
sections of the subsidiary coil are joined in.
The switch may be operated by hand but it is preferred to operate it auto-
matically by means of a centrifugal governor, by an electric governor, by a
tachometer or by any other similar device.
When the whole or a part of the subsidiary coil has been brought into circuit
as and for the purpose hereinbefore described, the principal factor in the main-
tenance of the stability of the magnetic field is the counter magnetic effect. This
counter effect is however assisted by the increased resistance and may to some
extent be regulated by employing for the subsidiary coil or including in its circuit
wire of greater or less resistance.
In order that our invention may be more readily understood we have hereto
appended a sheet of drawings which illustrate diagrammatically an improved
dynamo and its accessories.
A represents a dynamo which may be of any ordinary or suitable construction
and the field magnets of which are provided with a main or energising coil B.
A subsidiary coil C, wound in such a manner that a current passing through it
induces an opposing magnetism to that induced by the main coil is also placed
upon the field magnets. Under normal conditions or at a low speed, as illustrated
by the drawing, the end of the main coil is in circuit through the switch I) with
the lamps or the like E, and the whole of the subsidiary coil is cut out.
Should the speed of the vehicle or the driving mechanism increase, the switch I)
is moved so as to come into contact with the next stud and thus put a few turns
or a section of the coil C into the circuit. The coil C being connected to the coil B
the current passing through the former or through part of it sets up a magnetism

page_text: opposed to that set up by the passage of the current through the latter and thus
prevents any effective increase of magnetism consequent upon the increase of speed.
Should the speed continue to increase, further sections or all of the subsidiary coil
may be placed into the circuit.
The movement of the switch 1) may be effected by hand or automatically, as for
example, by means of the governor F which may be driven from the driving
mechanism.
It will of course be understood that other forms of dynamos than that
represented may be employed and that two or more main or subsidiary coils may
be used.
By means of our invention we are also enabled, when the machine is run at a
constant speed, to control the output.
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 a dynamo electric machine, the combination with the main energising
coil of a subsidiary opposing coil and devices by means of which any part or all of
the subsidiary coil may be included within or cut out from the circuit, sub-
stantially as and for the purpose hereinbefore described and as illustrated by the
accompanying drawing.
2. A dynamo electric machine constructed and arranged substantially as and
for the purpose herein before described and as illustrated by the accompanying
drawing.
Toted this 1st day of December AD. 1897.
W. E. HEYS & SON,
Agents for the Applicants.