Improvements in the Method of and Means for Preventing Electric Sparking at Contacts in Circuits, Including Electro-magnet Coils or other Coils or Conductors, in which a Self-inductive or Sparking Capacity Exists.
Year: 1899

page_text: Date of Application, 19th Sept., 1899
Complete Specification Left, 15th Feb., 1900-Accepted, 28th Apr., 1900
PROVISIONAL SPECIFICATION.
Improvements in the Method of and Means for Preventing Electric
Sparking at Contacts in Circuits, Including Electro-magnet Coils
or other Coils or Conductors, in which a Self-inductive or Sparking
Capacity Exists.
A communication from abroad by CHARLES LUMAN BUCKINGHAM, of 195, Broad-
way, in the City, County and State of New York, United States of America,
Lawyer.
I, WILLIAM LLOYD WISE, of 46, Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, do hereby declare
the nature of this invention to be as follows:
:--
Ordinarily, in a circuit including a coil of wire surrounding an iron core,
large sparks will appear upon breaking said circuit. This, however, I have
found may be very largely avoided by a special winding involving no greater.
length of wire for an equal magnetic pull, or an additional expense in con-
struction.
In the drawings Figure 1 represents a circuit including an electro-magnet coil
surrounding an iron core, and an apparatus for opening and closing the circuit.
In this case there is a continuous winding from one convolution to the next
throughout the coil.
+
Fig. 2 shows a magnet wound with two parallel wires, 1, 2. In this case,
adjoining convolutions are parts of separate coils or wires.
a
Fig. 3 illustrates an electro-magnet of the form shown in Fig. 2, with the
two separate coils joined together to form a circuit including battery with
key and contact e, or other suitable device for opening and closing the circuit:
Fig. 4 shows an arrangement of four wires instead of the two shown in Fig. 2.
Fig. 5 shows a magnet wound with alternate sections rather than with a
single winding of two wires side by side.
With the arrangement shown in Fig. 1. upon opening the circuit between
armature lever and contact e, a large spark will appear. Between the lever e
and contact e in Fig. 3, however, the spark is many times reduced.
In the arrangement of Fig. 3, the right end of the wire 1 is carried
back to the left end of wire 2, thus forming the convolutions of the magnet
into a continuous circuit; but, in this case, the convolution h of wire 1 and
the convolution of wire 2 are separated by practically one-half of the
voltage consumed by the coil or electro-magnet, and the same is true of neigh-
boring convolutions throughout the coil; that is to say, every two neighboring
convolutions are separated by one-half of the voltage between the two extreme
terminals of the device. This is apparent from the fact that current proceeds
from the positive pole of battery will run throughout all the convolutions
of the wire 1 before it reaches-the convolution of wire 2. Of course, if
the magnet were wound as in Fig. 1, adjoining convolutions would be separated
by only a very small voltage,

page_text: It is, of course, not necessary that the two wires 1 and 2 be wound side by
side as two strands of one, as approximately the same result will be obtained
if the two wires were wound in small alternate sections, as shown in Fig. 5.
Thus it is found that by winding an electro-magnet or solenoid with two wires
and connecting them as shown in Fig. 3, the spark at points of rupture may be
almost wholly eliminated. The same result may also be approximately obtained
by winding the magnet with three, four or more wires and connecting them
in such manner that all the convolutions of the magnet shall be brought into one
continuous circuit. An arrangement of four wires instead of two is shown in
Fig. 4.
It is well known that the presence of an iron core will greatly increase sparking
effects; our invention, however, is useful though in a less degree, where only
solenoids are used.
1000
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.
Improvements in the Method of and Means for Preventing Electric
Sparking at Contacts in Circuits, Including Electro-magnet Coils
or other Coils or Conductors, in which a Self-inductive or Sparking
Capacity Exists..
A communication from abroad by CHARLES LUMAN BUCKINGHAM, of 195, Broad-
way, in the City, County and State of New York, United States of America,
Lawyer.
I, WILLIAM LLOYD WISE, of 46, 'Lincoln's Inn Fields, in the County of
London, Consulting Engineer and Chartered Patent Agent, 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:-
Ordinarily, in a circuit including a coil of wire surrounding an iron core,
large sparks will appear upon breaking the said circuit. This, however, the
communicator has found may be very largely avoided by a special winding in-
volving no greater length of wire for an equal magnetic pull, or an additional
expense in construction.
'
In the drawings filed with my Provisional Specification, Fig. 1. represents a
circuit including an electro-magnet coil surrounding an iron core, and an
apparatus for opening and closing the circuit. In this case, there is a con-
tinuous winding from one convolution to the next throughout the coil.
Fig. 2 shows a magnet wound with two parallel wires, 1, 2.
In this case,
adjoining convolutions are parts of separate coils or wires.
Fig. 3 illustrates an electromagnet of the form shown in Fig. 2, with the
two separate coils joined together to form a circuit including a battery with
a key and contact e or other suitable device for opening and closing the circuit.
Fig. 4 shows an arrangement of four wires instead of the two shown in Fig. 2.
Fig. 5 shows a magnet wound with alternate sections rather than with a
single winding of two wires side by side.
With the arrangement shown in Fig. 1, upon opening the circuit between the
armature lever and the contact e, a large spark will appear. Between
the lever and the contacte in the apparatus shown in Fig. 3, however, the
spark is many times reduced.

page_text: In the arrangement shown in Fig. 3, the right end of the wire 1 is carried
back to the left end of the wire 2, thus forming the convolutions of the magnet
into a continuous circuit; but, in this case, the convolution h of the wire 1 and
the convolution i of the wire 2 are separated by practically one-half of the
voltage consumed by the coil or electro-magnet, and the same is true of neigh-
bouring convolutions throughout the coil; that is to say, every two neighbouring
convolutions are separated by one-half of the voltage between the two extreme
terminals of the device. This is apparent from the fact that current proceeding
from the positive pole of the battery 6 will run throughout all the convolutions
of the wire 1 before it reaches the convolution of the wire 2. Of course, if
the magnet were wound as shown in Fig. 1, adjoining convolutions would be
separated by only a very small voltage.
It is, of course, not necessary that the two wires 1 and 2 be wound side by
side as two strands of one, as approximately the same result will be cbtained
if the two wires were wound in small alternate sections, as shown in Fig. 5.
Thus it is found that by winding an electro-magnet or solenoid with two wires
and connecting them as shown in Fig. 3, the spark at points of rupture may be
almost wholly eliminated. The same result may also be approximately obtained
by winding the magnet with three, four, or more wires and connecting them
in such manner that all the convolutions of the magnet will be brought into one
continuous circuit. An arrangement of four wires instead of two is shown in
Fig. 4.
It is well known that the presence of an iron core will greatly increase sparking
effects; the invention, however, is useful, though in a less degree, where only
solenoids are used.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. The method of protecting contacts against destructive sparking in circuits
including electro-magnets or solenoids traversed by currents which would other-
wise produce such sparking, which consists in winding the magnets with two or
more wires and connecting the said wires in such manner that when two are
employed the terminal of the first will be joined with the beginning of the
second, or when three are employed the terminal of the first will be joined with
the beginning of the second and the terminal of the second with the beginning
of the third, and so on, in accordance with the number of strands or wires
employed, the reciprocal action of the windings upon each other serving prac
tically to neutralize the tendency to destructive sparking, in the manner shown
and described.
2. Means for preventing electric sparking at contacts in circuits including
electro-magnet coils or solenoids in which a self-inductive or sparking capacity
exists, substantially as herein before described with reference to and shown respec-
tively in Fig. 3, in Fig. 4, and in Fig. 5 of the drawings filed with my Pro-
visional Specification.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.