Improvements in Electro-motors and Dynamos.
Year: 1895

page_text: Date of Application, 30th July, 1895
Complete Specification Left, 30th Apr., 186-Accepted, 30th July, 1896
PROVISIONAL SPECIFICATION.
Improvements in Electro-motors and Dynamos.
We, THOMAS Drake HollicK, and FREDErick William HOLLICK,
both of 604, Commercial Road East, in the County of Middlesex, do hereby
declare the nature of this invention to be as follows:-
In many applications of electric motors, it is very desirable that, whilst the
electro-motive force remains practically constant, the speed should be capable of
being regulated so that it may be varied as required by the variations of loal, or
the work to be done.
For instance, taking the case of a tramcarriage driven by an electro-motor, it is
requisite that the attendant on the car should be able to adjust the speed of the
motor to suit the constantly changing requirements of the journey ;-for instance,
the difference in the load carried, the ascent and descent of inclines, the starting
and stopping of the car and the like.
Various methods have been proposed to effect the desired object, such as
varying the relative positions of the armature and field magnets to each other,
the use of "resistances," and the like, but these methods have hitherto proved
inefficient, or objectionable.
By our present invention we are able to attain the required results simply, and
efficiently, whilst the desired variation of speed is effected within very wide
limits.
Assuming that our invention is to be applied to an electro-motor used for the
purpose of propelling a tramear, we use a motor provided with an ordinary armature
of sufficient length and having a commutator of the usual kind, and field-magnets
preferably shunt-wound in the ordinary well-known way.
The field magnets are carried steadily and rigidly in guides, so that they can be
moved longitudinally or in a direction parallel with the armature spindle, for a
sufficient distance, and upon the armature spindle we fit and fix a second armature
suitably wound (as hereinafter described) and adjoining, or close to, the first
armature and also provided with a commutator.
The action of our improved apparatus is as follows:-
:-
When the field magnets are in such a position in their guides that they entirely
surround or enclose the first armature, (in the direction of their length), the armature
and shaft will revolve at a certain definite speed. If now the field magnets are
moved in their guides in the direction of the second armature, until one half only of
the length of the latter is surrounded by them, the speed of the armature will be
double, and so on proportionally. The movement of the field magnets as described
will however bring them partly over the second armature.
We find, however, by experiment, that the action described (that is to say the
increase of speed of the armature as the field magnets are withdrawn from it)
cannot be continued indefinitely with efficiency. In the case, for example, of an
armature fifteen inches long and nine inches diameter (which proportions we have
found to give good results), an increase of speed up to say about four to one can
be obtained.
Whilst the field magnets have been moved as described until they partly surround
the second armature, we allow the circuit of the conducting wires of the latter to

page_text: remain open, and we find that the iron core with which this armature is providel has
the effect of keeping the magnetic field in proper condition.
Supposing now that, say, three inches of the first arm iture still remain surrounded
by the field magnets, whilst about twelve inches of the latter surrounds the adjoining
part of the second armature.
We wind the latter in such manner and with such conducting wire that a length
of twelve inches of the armature will give a speed equal to or somewhat greater than
the highest speed of the first armature.
At this speed, therefore, attained as above described the connection through
the first armature is switched off by a suitable switch and the connection through
the second armature is switched on. In this condition, we can still further
increase the speed of the armatures and shaft, by moving the field magnets back in
the guides in a direction opposite to that first described, until a pɩrt only of
the second armature is surrounded by them, their overhanging part surroun ling a
corresponding part of the first armature,-(adjoining the second one), the
conducting wire circuit of which remains open, and its iron core serves to keep
the magnetic field in proper order, as in the case of the second armature as already
described.
Assuming such a motor as that just described makes one hundred revolutions
per minute when the whole of the first armature is surrounded by the field
magnets, and that when the latter have been shifted as describe the speed
is increased to four hundred revolutions per minute, then by bringing the second
armature into operation as described, the speed can be maintained; or by
switching off the first armature and switching on the second, and moving back
the field magnets so as to uncover one half of the length of the secon armature,
a speed of about double the above-or (say) eight hundred revolutions--can be
attained.
We find that by properly proportioning the various parts, a motor_constructed
in the novel manner described is easily operated and very efficient, and resistances
of the kind ordinarily used for starting and the like, may be dispensed with.
The field magnets may be moved in their guides in the manner described, by means
of a lever, screw, or other equivalent device of any of the well-known kinds,
operated by an attendant; or a governor of any suitable kind may be used, by
which when the speed of the motor increases unduly, the field magnets are moved
longitudinally a sufficient extent and in the proper direction either directly by the
governor, or by electrical power set in operation by suitable contacts made by the
governor when a certain speed has been reached, or by equivalent mechanical or
electrical means.
Our invention may be applied not only to electrical motors for actuating
tramcars, electric cranes, or other machinery, but to dynamos, the action being of
course inverted in the case of its application to the generation of electricity, as
compared with that above described for its application to motors for the utilization
of electricity.
We do not confine ourselves to any particular proportion of the parts, which may
be varied more or less, as may be found desirable to suit different circumstances
and conditions.
The details of construction and of the several parts of the apparatus may also be
varied to any required extent.

page_text: We, THOMAS DRAKE HOLLICK, and FREDERICK WILLIAM HOLLICK,
both of 604, Commercial Road East, in the County of Middlesex, 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, and accompanying drawings, that is to say :--
In many applications of electric motors, it is very desirable that, whilst the
electro-motive force remains practically constant, the speed should be capable of
being regulated so that it may be varied as required by the variations of load, or
the work to be done.
For instance, taking the case of a tram carriage driven by an electro-motor, it
is requisite that the attendant on the car should be able to adjust the speed of the
motor to suit the constantly changing requirements of the journey -for instance,
the difference in the load carried, the ascent and descent of inclines, the starting and
stopping of the car and the like.
Various methods have been proposed to effect the desired object, such as
varying the relative positions of the armature and field magnets to each other, the
use of resistances," and the like, but these methods have hitherto proved insufficient
or objectionable.
By our present invention we are able to attain the required resuits simply, and
efficiently, whilst the desired variation of speed is effected within very wide
limits.
Assuming that our invention is to be applied to an electro-motor used for the
purpose of propelling a tramcar, we use a motor provided with an ordinary armature
of sufficient length and having a commutator of the usual kind, and field-magnets
preferably shunt-wound in the ordinary well-known way.
The accompanying drawings are in illustration of our invention, Figure 1
representing a side view, and Figure 2 an end view.
The field magnets, of which a, a represent the poles and b, b₁ the exciting
coils, are carried steadily and rigidly in or upon guides c, so that they can be
moved longitudinally or in a direction parallel with the spindle of the armature d,
(which is provided with a suitable commutator e), for a sufficient distance, and upon
this armature spindle we fit and fix a second armature suitably wound (as herein-
after described) and adjoining, or close to, the first armature d, and also provided
with a suitable commutator or commutators at g.
The action of our improved apparatus is as follows:-
C
When the field magnets a are in such a position in or on their guides c that they
entirely surround or enclose the first armature d, (in the direction of their
length), as shewn in Figure 1, the armature and shaft will revolve at a certain
definite speed. If now the field magnets a are moved in their guide in the direction
of the second armature f, until one half only of the length of the first armature d
is surrounded by them, the speed of the armature will be double, and so on
proportionally.
The movement of the field magnets a as described will however, of course, have
brought them partly over the second armature f.
We find, however, by experiment, that the action described (that is to say the
increase of speed of the armature as the field magnets are withdrawn from it) cannot
be continued indefinitely with efficiency. In the case, for example, of an armature
fifteen inches long and nine inches diamoter such as is shewn at d (which proportions
we have found to give good results), an increase of speed up to, say about four
to one, can be obtained.
Whilst the field magnets a have been moved as described until they partly surround

page_text: the second armature, we allow the circuit of the conducting wires of the latter to
remain open, and we find that the iron core of this armature has the effect of keeping
the magnetic field in proper condition.
Supposing now that, say, three inches of the first armature d still remain
surrounded by the field magnets a, whilst about twelve inches of the latter surround
the second armature f.
The latter has been wound in such manner and with such conducting wire that a
length of twelve inches of this armature will give a speed equal to, or somewhat
greater than, the highest speed of the first armature d.
At this speed, attained as above described, the connection through the first
armature d is switched off by a suitable switch, and the connection through the
second armaturefis switched on. In this condition, we can still further increase
the speed of the armatures and their shaft, by moving the field magnets a back,
in or on their guides c, in a direction opposite to that last described, until a
part only of the second armature f is surrounded by then, their overhanging
part surrounding a corresponding part of the first armature d, the conducting
wire circuit of which remains open, and its iron core serves to keep the
magnetic field in proper order, as was the case with the second armature
already described.
as
Assuming that such a motor as that just described makes one hundred revolutions
per minute when the whole of the first armature d is surrounded by the field
magnets a, and that when the latter have been shifted as described the speed is
increased to four hundred revolutions per minute, then by bringing the second
armature into operation as described the speed can be maintained; or by switching
off the connection through the first armature d and switching on the connection
through the second armature f, and moving back the field magnets a so as to
uncover one half of the length of the second amature f, a speed of about double
the above or (say) eight hundred revolutions-can be attained.
We find that by properly proportioning the various parts, a motor constructed
in the novel manner described is easily operated and very efficient, and resistances
of the kind ordinarily used for starting, and the like, may be dispensed with
The field magnets a may be moved in or on their guides c in the manner
described, by means of a lever, screw, or other equivalent device of any of the well-
known kinds, (in Figure 1 they are shewn actuated by a chain h, attached to them
and passing over pullies i, i, the chain being driven by a handle k,) operated by an
attendant; or a governor of any suitable kind may be used, by which when the
speed of the motor increases unduly, the field magnets are moved longitudinally
through a sufficient distance, and in the proper direction, either directly by the
governor, or by electrical power set in operation by suitable contacts made by the
governor when a certain speed has been reached, or by equivalent mechanical or
electrical means.
Our invention n.ay be applied not only to electricabmotors for actuating tramcars,
electric cranes, or other machinery, but to dynamos, the action being of course, as
will be easily understood, inverted in the case of its application to the generation of
electricity, as compared with that above described for its application to motors for
the utilization of electricity.
We do not confine ourselves to any particular proportion of the parts, which may
be varied more or less as may be found desirable to suit different circumstances and
conditions; and the details of construction and of the several parts of the apparatus
may also be varied to any required extent.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
:-
1. In electrical motors, the method of regulating the speed of the motor, consisting
in fixing two armatures having iron cores, upon the motor shaft, the ends of such
armatures being adjoining or near each other, in combination with field magnets

page_text: surrounding the armatures, and of the length of one of the armatures, with means
for altering and adjusting longitudinally the position of the field magnets round the
armatures, and with means for switching the coils of either armature on or off,
substantially as described and illustrated.
2. The method of construction in which the second or shorter armature is wound
in such manner that when the field magnets entirely surround it, whilst surrounding
a portion only of the first or larger armature, they will revolve at about the same
speed as that given by that part of the first armature which remains surrounded by
the field magnets, substantially as described and illustrated.
Dated this 30th day of April 1896.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicants.