Improvements in Apparatus for Controlling Electric Motors.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Controlling Electric Motors.
We, SIEMENS BROTHERS & CO. LIMITED, of 12, Queen Anne's Gate, Westminster,
S.W., Electrical Engineers, and ARTHUR JAMES STOPHER, of 47, Elliscombe Road,
Old Charlton, Kent, Mechanical Engineer, do hereby declare the nature of this
invention to be as follows:-
Electric locomotives having more than one motor require, for the starting of
their motors a series of operations to direct the electric current in such a way as
to introduce and cut out resistances and to work the motors first in series and then
in parallel. Thus when, for instance, there are two motors, the current is first
directed through the resistance and the motors in series, secondly the resistance
is cut out, the motors still being connected in series, thirdly, the resistance is again
introduced and one of the motors is short circuited, fourthly, the current flows
through the resistance and both motors in parallel, and finally the resistance is
cut out and the motors continue in parallel. Now this invention relates to
apparatus whereby operations such as are above indicated are automatically
determined to occur in proper sequence, the operator having only to move a suit-
able handle. The apparatus is also arranged to prevent sparking at those parts
which might be injured, the sparking being confined to a suitable sparking switch.
For this purpose a winch handle is connected by suitable gear to a rotary com-
mutator in form of a hollow cylinder having on its periphery insulated conducting
strips, which as the cylinder revolves, are brought in their proper order in contact
with suitable terminals connected to the motors, resistances and sparking switch.
There are also arranged within the cylinder such connections as are required of
the conducting strips to one another. At one end of the commutator cylinder
is a disc having a circular hollow cut in its circumference, this hollow being
engaged by the edge of a disc which is geared to a reversing switch and which
has two circular hollows engaged by the periphery of the commutator disc, the
two discs thus interlocking one another in such a manner that the commutator
cannot be moved unless the reversing switch is first moved to one of two positions
and the reversing switch cannot be moved unless the commutator is in such a
position that no current is passing.
a
cur-
that
A cam or other suitable device geared to the commutator actuates
and the conducting
the sparking switch which has carbon contacts;
strips of the commutator are arranged so that the path of the
rent for each succeeding operation is prepared in such manner
Thus the
the reversal of the sparking switch completes the circuit.
circuit being never interrupted on the commutator no sparking occurs except
at the sparking switch. When the commutator is rotated in the opposite direction
the sequence of operations is reversed. It is convenient to gear to the commutator
an indicator by which the operator can see its position. The number of conducting

page_text: strips and contacts of the commutator necessarily depends upon the number of
motors that have to be started, and the number of successive steps required.
Dated this 15th day of Nov 1807
ABEL & IMRAY,
Agents for the Applicants.
Improvements in Apparatus for Controlling Electric Motors.
We, SIEMENS BROTHERS & CO. LIMITED, of 12, Queen Anne's Gate, Westminster,
S.W., Electrical Engineers, and ARTHUR JAMES STOPHER, of 47, Elliscombe Road,
Old Charlton, Kent, Mechanical 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:-
-
Electric locomotives having more than one motor require, for the starting of
their motors, a series of operations to direct the clectric current in such a way as
'to introduce and cut out resistances and to work the motors first in series and then
in parallel. Thus when, for instance, there are two motors, the current is first
directed through the resistance and the motors in series, secondly, the resistance
is cut out, the motors still being connected in series, thirdly, the resistance is again
introduced and one of the motors is short circuited, fourthly, the current flows
through the resistance and both motors in parallel, and finally, the resistance is
cut out and the motors continue in parallel. Now this invention relates to
apparatus whereby operations such as are above indicated are automatically
determined to occur in proper sequence, the operator having only to move a suit-
able handle. The apparatus is also arranged to prevent sparking at those parts
which might be injured, the sparking being confined to a suitable sparking switch.
We shall describe this invention by way of example as applied to two electric
motors referring to the accompanying diagrams and drawings.
Figure 1 is a diagram indicating eight successive electrical connections determined
by the apparatus.
Figure 2 is a diagram shewing development of the commutating cylinder with
the conducting segments and connection as arranged thereon.
Figure 3 is a longitudinal section of the apparatus.
Figure 4 is an end elevation.
Figures 5 and 6 are transverse sections respectively on the lines 5-5 and 6-6
of Figure 3.
Figures 7 and 8 are respectively part longitudinal and transverse sections to
an enlarged scale shewing the fixing of the commutator segments.
Figure 9 is a transverse section and Figure 10 is a part side elevation shewing
the contacts for the commutator segments.
Referring first to Figures to 10 inclusive, A is a closed casing within which is
mounted in bearings on frames B a commutating cylinder C, having fixed upon
it a number of conducting segments C¹. These, as shewn more particularly in
Figures 7 and 8 are insulated from the cylinder by insulators ce¹, also the
stems C by which the segments are held have where required attached to them
conductors C by which they are electrically connected to others of the segments.
The segments as the cylinder revolves (as will hereafter be described) pass
between conducting springs D fixed to metal straps D¹ on a girder D³ which is
attached to the framing B but the straps D¹ are insulated from the girder by
insulators and d. Some of the straps D1 are electrically connected to others
of them by diagonal bars D³. The cylinder C is driven at a slow speed by a hand

page_text: wheel E through gearing e el ee³, e being a pinion on the hand wheel,
el and e² being a wheel and pinion on a countershaft F, and 3 being a wheel on
the shaft of the cylinder C. On the countershaft F is fixed a cam F¹ which, in
each revolution causes an arm G, pivotted at g to a bracket gl fixed to the framing B,
to make a stroke from right to left and from left to right, resting for a time in
each position between contact springs H which are fixed on brackets being
insulated therefrom by insulators . By the gearing eel the countershaft F
and its cam F make one revolution for two revolutions of the hand wheel, and
by the gearing e²e the commutating cylinder makes one revolution for four of
the countershaft F and therefore for 8 of the hand wheel E.
Referring now to Figure 2 shewing the circumference of the commutating
cylinder and the segments C¹ thereon developed the positions of the switch arm G
to the right or left are indicated by the dotted crossed rectangles K and K¹
respectively; and the top diagram indicates the condition of the circuits when
the motors are at rest, this diagram corresponding with the last in VIII of
Figure 1. Referring now to Figure 1 which shews eight different conditions
of the circuits, in each case with a preparatory condition, indicating resistances
and m m the two motors and the dotted lines in the upper figures indicating
paths prepared for the current when the switch arm G shall be moved over. The
lower figures in each of the eight diagrams shew the paths for the current com-
pleted when the switch arm G is moved over.
The eight conditions of the circuits are therefore as follows:-
I. All the resistances are in circuit and the motors are in series.
JI. Part of the resistance is cut out.
II. All the resistance is cut out.
IV. Part of the resistance is again introduced and the second motor is short
circuited.
V. The motors are connected in parallel.
VI. Part of the resistance is cut out.
VII. All the resistance is cut out.
VIII. The circuit is open stopping the motors.
As in no case is there complete interruption of the circuit on the commutator
there is no sparking between any of the segments C and springs D; when any
sparking occurs, it is only at the switch as the arm G leaves the contact springs H.
Although we have described the apparatus as applied to two motors, obviously
by employing suitable numbers of commutator segments and resistances, suitably
arranged, three or more motors might be similarly controlled. It is convenient
to connect a visible index to the commutating cylinder so that the operator may
at any time see its position. Also it is convenient, though not necessary, that the
hand wheel should be geared to the cylinder in the proportion of 8 to 1, because the
operator knows that by each turn of his handle he completes a change of circuit.
In cases where a greater or less number of changes of circuit are required, the
gearing would be by preference arranged to correspond with the number of changes.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:
-
1. In apparatus for controlling electric motors the combination of a cylinder
having contact segments arranged on its circumference, means of causing the
cylinder to revolve spring contacts for the segments a cam geared to the cylinder
and a switch having an arm engaged with the cam and adapted to vibrate from
one contact to another, substantially as and for the purpose set forth.
2. In apparatus such as is above referred to the arrangement of the segments
of the commutator in relation to the movement of the vibrating switch in such a
manner that the current path for each succeeding operation on the motors is pre-

page_text: pared but not completed till the switch has made a corresponding stroke,
substantially as and for the purpose set forth.
ABEL & IMRAY,
Agents for the Applicants.