Improvements in or applicable to Switches for Electro Motors and the like Purposes.
Year: 1896

page_text: Date of Application, 29th Oct., 1896
1007
10th Cont
1007
PROVISIONAL SPECIF
Improvements in or applicable to Switches for Electro Motors
and the like Purposes.
We, JOSEPH PLATT HALL, of Gorse Bank, Oldham, Electrical Engineer, and WILLIAM
HENRY SEVILLE CRAVEN, of Heaton Villas, Cheetham Hill, Manchester, Engineer, do
hereby declare the nature of this invention to be as follows:-
Our said invention relates to the combination with an electric current reversing
switch of a liquid resistance in such a manner that the break of the circuit takes place
at the surface of the liquid instead of on the reversing switch the commutator of which
remains inert at the moment the break of the circuit takes place.
This is effected partly by the arrangement of the angles at which the contacts of the
commutator are placed with regard to each other and partly by the motion relative
thereto of the plate or plunger which enters the resistance tank.
As applied for example to a series wound motor the switch has a commutator
with brushes for changing the direction of the current and directing it through
the plate or plunger and the liquid resistance and thence back by the return main
to the dynamo.
The depth of the plate or plunger in the liquid adjusts the resistance in the
circuit and when the current has attained a maximum the liquid resistance may
be cut out of circuit by a suitable switch either operated by or from the plunger or
independently thereof.
Other parts of our said invention relate to details of construction having for their
object to augment the angular rotation of the commutator as compared with the lever
by which it is operated and also to obtain a relatively long range of action for the
plate or plunger of the resistance as compared with the commutator or its controlling
lever. To this end the controlling lever is connected to the commutator or to a
projection therefrom in such a manner as to form a compound lever therewith as for
instance by using a controlling lever having its fulcruma set excentrically to the
commutator and connected thereto by a pin and slot. We may employ toothed or
other gearing for the same purpose.
To increase the range or traverse of the plunger of the resistance the latter is
operated from the commutator axle by a crank and links levers excentrics a toothed
sector or pinion and a rack or other like multiplying gear either alone or in combina-
tion with each other.
In some cases we control the plunger of the resistance and the commutator by
toothed gearing or levers operating on the commutator and on the plunger inde-
pendently of instead of through each other either by a single controlling handle or by
separate handles. Suitable gearing or devices are interposed between the controlling

page_text: handles and the commutator and the plunger of the resistance for obtaining the such
relative movements of the one to the other as to ensure the inertness of the com-
mutator while the break of the circuit takes place so as to confine the latter to the
surface of the liquid.
By suitable modifications in the details our said invention may be applied not only
to a series wound motor but also to shunt or other arranged motors.
Dated this 28th day of October 1896.
E. T. WHITELOW, A.M. Inst.C.E..
70, Deansgate, Manchester, Agent for the Applicants.
Improvements in or applicable to Switches for Electro Motors.
and the like Purposes.
We, JOSEPH PLATT HALL, of Gorse Bank, Oldham, Electrical Engineer, and
WILLIAM HENRY SEVILLE CRAVEN, of Heaton Villas, Cheetham Hill, Manchester,
Engineer, 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:-
Our said invention relates to the combination with an electric current reversing
switch of a single liquid resistance in such a manner that the break (or make)
of the circuit takes place at the surface of the liquid instead of on the com-
mutator which remains inert at the moment the break (or make) of the circuit
takes place.
In order that our said invention may be more clearly understood we will describe
the same with reference to the accompanying drawings which by way of example
illustrate its application to a switch for operating a series wound reversible motor, i.e.
a motor which may he caused to rotate in one direction or the other according to the
direction in which the current passes through its armature. For convenience rota-
tion in one (arbitrarily chosen) direction is herein called direct and rotation in the
opposite direction is called reverse. In all the drawings the same letters refer to the
same parts.
Sheet I of the accompanying drawings contains 4 diagrams illustrating in a
schematic form the main features of our said invention. -and + indicate the terminals
of the wires connected to the source of the electric current. m indicates the motor
armature and m² the motor series coils.
a is the barrel of the commutator or current reverser. 61 62 63 64 are the brushes
working in contact therewith. The commutator has conducting surfaces a¹ and insu-
lating or non-conducting portions a² and the direction of the current is determined as
usual by the relative position of the conducting surfaces al and the brushes. e is a
resistance tank containing a suitable solution of chemicals in water to reduce its
resistance. The depth of the liquid is kept constant by an overflow pipe or hole
placed at a suitable height. A plate or plunger d connected with the brush b¹ makes
or breaks the circuit by entering or being withdrawn from the liquid in the tank e.
In the diagrams in Sheet I the commutator a is rotated and the plunger d is moved
at the same time by the handle e mounted on the axis of the commutator and con-
nected to the plunger d by a link c. The liquid level and the disposition of the contact
surfaces a¹ of the commutator are so arranged that the current is broken (or made) by
the plunger & leaving (or entering) the liquid while the commutator brushes are in
contact with the contact surfaces of the commutator. It follows from this arrangement
that no current is passing during the time in which the brushes leave one contact
surface pass the insulations and arrive on the next contact surfaces. In effect the

page_text: change of direction of the current is made while the current itself is cut off and
thereby the great advantage is gained that there is no sparking on the com-
mutator itself thereby removing a serious defect which leads to the rapid destruction
of the commutator. The diagrams on Sheet I show the relative positions of the parts
at various times.
In diagram I the notor is being driven direct and the current is about to be
reversed. By throwing over the handle e to the left the plunger d rises and the
commutator a turns to the left. (Confining one's attention for the moment to the
brush ). The plunger d is lifted clear of the liquid and breaks the circuit before
the brush has quite reached the end of the left hand conducting surface. This
absence of current continues while the brush & leaves the conducting surface passes
through the position shown in diagram I and attains to that shown in diagram 2 i.e.
on to the next conducting piece. The direction the current will take (when allowed
to pass) has now been changed. A further movement of the handle c to the left dips
the plunger d into the liquid (see diagram 2) thus completing the circuit and
driving the motor in the reverse direction. The remaining brushes 61 62 63 make and
break contact with the conducting surfaces in a similar manner as will be well
understood.
For convenience the brush b has been described as moving from one place to
another. This is so only in a relative sense inasmuch as the brushes are stationary it.
is the cominutator which moves.
The remaining drawings illustrate other parts of our said invention which relate
to means for carrying into practical effect that part of our invention which has been
herein before described.
In Sheet 2 Fig. 4 is a sectional elevation and Figs. 4" and 4" are end elevations
from opposite ends of Fig. 4. In these figures the controlling lever c has its
fulcrum c¹ set excentrically to the axis of the commutator with which it is connected
by a pin el taking into a slot in the lever a so as to form a compound lever whereby
the angular rotation of the commutator is augmented as compared with that of the
controlling lever. On the axle of the commutator is a toothed sector f engaging
with a pinion f¹ formed on or attached to a crank f³ the crank pin of which is
connected by a link f with the plunger d. This combination of mechanism gives a
long range of action to the plunger as compared with the commutator and its con-
trolling lever. In Sheet 3 Fig. 5 is an elevation partly in section, Fig. 5* is an end
elevation (from the right hand of Fig. 5 illustrating an alternative arrangement
operating the plunger. In this case the controlling lever c is attached direct to the
commutator a the axle of which carries a double slotted plate with which engages a
pin and bowl g which carries the plunger plate d and which is mounted in a slide
block g2 carried in guides g. The rotation of the commutator tilts the slotted
plate g and thereby lifts or lowers the plunger.
In Sheet 4 Fig. 6 in an end elevation and Fig. 6 is a sectional elevation of an
arrangement for operating the plunger and the commutator independently from a
single controlling handle instead of through each other. h is the handle mounted on
a crank or hand wheel h¹ the axle of which carries a worm he gearing into a worm
wheel h³ the axle of which carries a pinion hand a crank h. The latter is
connected by a link to the plunger d which is guided at h in suitable slideways.
The pinion h gears into the sector h8 which is secured to the axle of the com-
mutator a and causes the latter to rotate simultaneously with the rise or descent of
the plunger.
In all the arrangements the depth of the plate or plunger in the liquid adjusts
the resistance in the circuit and when the current has attained a maximum the
liquid resistance may be cut out of circuit by a suitable switch either operated from
the plunger or independently thereof. In the drawings various ways are shown of
effecting this.
In the arrangement shown in Sheet 2 (Fig. 4) a metal bar m is mounted on the
plunger and when the latter has reached its lowest point the ends of the bar m will
engage and make metallic contact with forks or recesses m¹ of the tank e. In

page_text: the arrangement shown in Sheet 3 the same end is obtained by a metallic pro-
jection m² engaging with a fork m³ on the descent of the plunger. In Sheet 4 a
cross bar m' simply comes into contact with the side of the tank when the plate
descends.
Any number of such commutators and plates may be mounted independently of
each other on a common tank as shown in Sheet 3.
In constructing such apparatus as hereinbefore described the usual precautions
must be taken to insulate the parts where necessary in order to prevent the current
short circuiting or taking the wrong direction as will be well understood by those
conversant with electrical machinery without further description.
Although for purposes of description we have described our invention as forming a
switch and cominutator for operating a series wound reversing motor it is to be
understood that with suitable modifications in the details and the connections our
said invention is also applicable to shunt or other motors or to other purposes where
it is required to make and break the circuit or to reverse the direction of an electric
current or currents.
Having now particularly described and ascertained the nature of our said 'inven-
tion and in what manner the same is to be performed we say we are aware that
it has been heretofore proposed to employ apparatus so arranged that the break or
make of the current has taken place on the surface of a liquid whilst the commutator
brushes were still in contact with the conducting surface of the commutator through
the intervention of an arrangement of two liquid containing vessels and two levers
one being in use for one direction of the current and the other for the other
direction.
We desire it to be understood that we do not claim the mere making and breaking
of the circuit at the surface of a liquid resistance nor do we make any broad or
general claim to apparatus of this class, but we declare that what we claim is:-
1. The combination of a single liquid resistance and an electric current reversing
switch or commutator in such a manner that the break (or make) of the current
takes place at the surface of the liquid while the commutator brushes are in contact
with the conducting surfaces of the commutator when the switch is operated so
that at the moment the brushes make or break contact with the conducting surfaces
of the commutator no current is passing between them substantially as set forth.
2. The combination of the excentrically set handle c the pin c¹ the commutator a
the sector f the pinion the crank f the link and the plunger d substantially as
and for the purpose set forth and described with reference to Figs. 4, 4, and 4 of
the accompanying drawings.
3. The combination of the lever c the commutator a the slotted plate g the sliding
Ein g and the plunger / substantially as and for the purpose set forth and described
with reference to Figs. 5 and 5 of the accompanying drawings.
4. The combination of the worm
link the plunger d with the sector
the worm 3 the pinion the crank the
and the commutator substantially as and
for the purpose set forth and described with reference to Figs. 6 and 6 of the
accompanying drawings.
Dated this 29th day of July 1897.
E. T. WHITELOW, A.M. Inst.C.E.
70, Deansgate, Manchester, Agent for the Applicants.