Improvements in and connected with Electrical Switches.
Year: 1898

page_text: r
PROVISIONAL SPECIFICATION.
Improvements in and connected with Electrical Switches.
EDWARD JOHN WADE (Electrical Engineer) of 84, Beechdale Road, Brixton Hill,
London, S.W., and The Electric Motive Power, Limited, (Motor Carriage Builders)
having registered offices at 17 Tower Royal, Cannon Street, London, E.C., do hereby
declare the nature of this invention to be as follows:-
Our invention relates to improvements in those classes of electrical switches which
are used for coupling up storage cells or other sources of E.M.F. in various combina-
tions of series and parallel, more especially with the object of controlling and varying
the E.M.F. applied to electric motors for traction and other purposes.
These switches as now constructed have certain disadvantages. In order to avoid
short-circuiting the cells, one combination has to be broken up before making another,
and the motor circuit has also to be broken and re-made with each charge of E.M.F.
The result is that the switch contacts are rapidly destroyed by the sparking that
ensues and the speed of the motor can only be varied in intermittent steps instead of
rising and falling in a continuous manner.
For example, suppose 12 cells or sets of cells are used and it is desired to couple
them up at will in 6 parallels of 2 each or 4 parallels of 3 each or 3 parallels of 4 each
or 2 parallels of 6 each. Numbering each cell or set of cells from 1 to 12, these four
working combinations may be represented as follows:-
No two of these combinations can be in circuit at the same time without short-
circuiting some of the cells, and therefore in passing from one to another, a distinct
gap or break has to be provided between each.
The object of our invention is to provide means whereby the cells may be altered
from one working combination to another without short-circuiting any of them and
For this purpose we
yet at the same time without breaking the main circuit.
introduce a number of intermediate combinations through which the changes are
effected, and we so arrange the contact pieces that circuit is always made on one
combination before it is broken on another.
Three intermediate stages or combinations are provided between each of the work-
ing combinations. In passing from one of the latter to another the first stage is to
cut out some of the parallels composing it but leaving one or more of them in circuit
to maintain the current. The second stage is to put back into the circuit in parallel
with those still there, part or all of the cells cut out, but grouped in series differently
according to the new E.M.F. it is desired to obtain. The third stage is to cut out the
remainder of the cells of the old grouping; and the contacts then pass to the next

page_text: working combination when all the cells out of circuit are put back in parallel with
those introduced at the second stage and in a similar series grouping.
According to our invention, in the case of 12 cells hereinbefore cited, the
combinations from 6 parallels of 2 each to 4 parallels of 3 each would be.
1, 2, 3, 4
+
5, 6, 7, 8
-
9, 10, 11, 12
+1,2,3,4-
+
{1, 2, 3, 4
(7, 8, 9, 10, 11, 12,
1, 2, 3, 4, 5, 6
+
+7, 8, 9, 10, 11, 12-
7, 8, 9, 10, 11, 123
Throughout a whole series of combinations arranged in this way, any two of them
directly adjacent to each other may be in circuit at the same time without short-
circuiting any of the cells, and the main circuit need never be broken.
In each case
the second of the intermediate combinations consists of unequal series of cells joined
in parallel with each other and there will therefore be a local current through the
switch from the greater to the lesser series. For this reason the E.M.F. in circuit
must not be varied too abruptly, but provided the two E.M.F.'s involved in any one
change are not in a greater ratio than 3 to 2 the currents through the local circuits
will not be excessive. Moreover as these local circuits are almost entirely free from
self-induction the sparking that occurs on breaking them is practically negligeable.
When a change of E.M.F. has to be effected which cannot be accomplished in the
manner hereinbefore described, as for instance when doubling or halving the E.M.F.
by changing the storage cells from two parallels to all in series or vice versa,
auxiliary resistances may be introduced into the circuit to diminish the sparking at
these points.
Our invention can be carried out in various ways, but the method we prefer is to
bring the terminals of, the cells or sets of cells or other sources of E.M.F. to a row of
fixed contact pieces and to connect them together as required for the various com-
binations by bridge pieces which are arranged in suitable sets on the periphery of a
cylindrical druin and can be brought into play one after another as it revolves. These
sets of bridge pieces must be placed sufficiently near to each other that one set makes
circuit with the fixed contacts before another set leaves them.
It will be understood that the intermediate combinations are only intended to be
in circuit momentarily when passing from one working combination to another for if
used continuously the cells would be run down unequally and some become exhausted
before the others.
E. J. WADE.
PERCY W. NORTHEY,
Managing Director.

page_text: Improvements in and connected with Electrical Switches.
EDWARD JOHN WADE (Electrical Engineer), of 84, Beechdale Road, Brixton Hill.
S.W., & THE ELECTRIC MOTIVE POWER COMPANY, LIMITED (Motor Carriage Builders),
having registered offices at 17, Tower Royal, Cannon Street, London, E.C.,
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 improvements in those classes of electrical switches which
are used for coupling up storage cells or other sources of E. M. F. in various combina-
tions of series & parallel, more especially with the object of controlling & varying the
E. M. F. applied to electric motors for traction & other purposes.
These switches as now constructed have certain disadvantages. In order to avoid
short-circuiting the cells, one combination has to be broken up before making another
& the motor circuit has also to be broken up before making another and the motor
circuit has also to be broken & re-made with each change of E. M. F. The result is
that the switch contacts are rapidly destroyed by the sparking that ensues and the
speed of the motor can only be varied in intermittent steps instead of rising and fall-
ing in a continuous manner.
For example, suppose 12 cells or sets of cells are used & it is desired that they can
be coupled up at will in 6 parallels of 2 each, or in 4 parallels of 3 each, or in 3
parallels of 4 each, or in 2 parallels of 6 each. Numbering the cells or sets of cells
from 1 to 12, these four working.combinations may be represented as follows:-
No two of these combinations can be in circuit at the same time without
short-circuiting some of the cells & therefore in passing from one to another, a
distinct gap has to be provided between each.
The object of the present invention is to provide means whereby the cells may
be altered from one working combination to another without short-circuiting any
of them, & yet at the same time without breaking the main circuit. For this
purpose we introduce a number of intermediate combinations, through which the
changes are effected, & we so arrange the contact pieces that circuit is always made on
one combination before it is broken on another.
Three intermediate stages or combinations are provided between each of the working
combinations.
In passing from one of the latter to another, the first stage is to cut out some of the
parallels composing it, but leaving one or more of them in circuit to maintain the
current. The second stage is to put back into the circuit in parallel with those still
there, part or all of the cells cut out, but grouped in series differently according to the
new E. M. F. it is desired to obtain. The third stage is to cut out the remainder of
the cells of the old grouping; and the contacts then pass to the next working
combination when all the cells out of circuit are put back in parallel with those
introduced at the scond stage, & in a similar series grouping.

page_text: According to our invention, in the case of 12 cells hereinbefore cited, the com-
binations from 6 parallels of 2 each to 4 parallels of 3 each would be,-
and from 4 parallels of 3 each to 3 parallels of 4 each,―
Throughout a whole series of combinations arranged in this way, any two of
them directly adjacent to each other may be in circuit at the same time
without short-circuiting any of the cells, and the main circuit need never be
broken.
In each case, the second of the intermediate combinations consists of unequal
series of cells joined in parallel with each other, and there will therefore be a local
current through the switch from the greater to the lesser series.
For this reason the E.M.F. in circuit. must not be varied.too abruptly, but provided
the two E.M.F".s involved in any one change are in a greater ratio than 3 to 2 the
currents through the local circuits will not be excessive. Moreover as these local
circuits are almost entirely free from self-induction the sparking that occurs on
breaking them is practically negligeable.
If desired the local currents may be still further reduced by arranging that when
two or more series of unequal number of cells are in parallel with each other, those
containing the greater number of cells shall have a small resistance inserted in series
with them which shall be cut out by short-circuiting at the same time that the lesser
series of cells are cut out.
When a change of E.M.F. has to be effected which cannot be accomplished in the
manner herein before described, as for instance when doubling or halving the E.M.F.
by changing the storage cells from two parallels to all in series or vice versa,
auxiliary resistances may be introduced into the circuit to diminish the sparking at
these points.
Our invention can be carried out in various ways, but the method we prefer is to
bring the terminals of the cells or sets of cells or other sources of E.M.F. to a row of
fixed contact pieces, and to connect these together as required for the various com-
binations by means of annular contacts, which are arranged in suitable sets on the
periphery of a cylindrical drum, & can be brought into play one after the other as
it is revolved. This form of the switch is illustrated in the accompanying drawing in
which :-
Figure 1 is a developed plan of the drum, showing the arrangement of contact
pieces necessary to couple up the cells, in the combinations herein before referred to,
that is to say, 6, 4, 3 and 2 parallels, together with the intermediate combinations for

page_text: passing from each one of these to the next. The position of each combination is
indicated by figures which correspond to those already used. Figure 2 is a lengthways
section through the drum (only one half of which is shown) when the contacts
required to give combination No. 2* are engaged with the fixed contacts, and it also
shows diagramatically the connections between the cells and the fixed contacts.
Figure 3 is a cross-section through the drum on the line x, y of Figure 1.
A A are a row of forked contact pieces mounted on some non-conducting material
or otherwise insulated from each other & provided with suitable means such as
threaded stems & nuts D whereby the wires from the storage cells may be
connected to them.
Against each terminal is marked which cell and which pole of the cell is connected
to it, assuming that 12 cells are used, numbered consecutively from +1 at one end
of the battery to
12 at the other. C is the drum. BB are annular contacts on
the drum which make connection by passing between the forks of the fixed contacts
A A. The drum is mounted on an axis E and is fitted with a handle F by which it
can be rotated.
Some of the contacts are simply bridge pieces for connecting two adjacent terminals
while others have to couple up terminals at some distance from each other and must
therefore be connected together as shown by the dotted lines.
The width of the fixed contacts must be such that they can never rest on more
than two combinations at the same time, for if three adjacent combinations are
bridged together, short-circuits will result.
The intermediate combinations are only intended to be in circuit momentarily when
passing from one working combination to another, and any suitable device may be
provided to indicate when this is effected, or to prevent the switch being left
continuously in a wrong position.
It obvious that the form of switch shown in the drawings and the special
combinations & number of cells can be varied, those herein before described being
given for purposes of illustration & example.
Having now particularly described and ascertained the nature of our said inven-
tion, & iu what manner the same is to be performed, we declare that what we
claim is :-
1. In electrical controller switches, the method of passing from one parallel
combination to another without breaking the motor or main circuit by first cutting
out one or more of the parallels, then re-introducing in parallel the whole or a
part of the cells cut out, but coupled up in a different series then cutting out
the remainder of the first parallels & finally re-introducing in parallel all
the cells out of circuit grouped according to the new series, substantially as set
forth.
2. In electrical controller switches, a set of contact pieces with which the terminal
of the cells or sets of cells or other sources of E.M.F. are connected in combination
with another set of contact pieces, arranged to contact with said first named set, the
positions of said two sets relatively to each being variable at will, & the number and
relative position of the contacts of said two sets being such that when one set is moved
relatively to the other set in making a change from one working combination of
cells to another working combination, intermediate combinations or stages are
produced and the new working combination obtained without short-circuiting
any of the cells and without breaking the main circuit substantially as set
forth.
3. In electrical controller switches, a set of contact pieces with which the terminals
of the cells or sets of cells or other sources E.M.F. are connected in combination with
another set of contact pieces on a revolvable drum, and arranged to contact with said
first named set, the number and relative position of the contacts of said two sets
being such that when one set is moved relatively to the other set in making a change
from one working combination of cells to another to another working combination,

page_text: intermediate combinations or stages are produced and the new working combination
obtained without short-circuiting any of the cells and without breaking the main
circuit, substantially as set forth.
E. J. 'WADE.
PERCY W. NORTHEY,
Managing Director.