Improvements in or connected with the Working and Welding of Metals by Electricity.
Year: 1893

page_text: Date of Application, 18th May, 1893-Accepted, 19th Aug., 1893
COMPLETE SPECIFICATION.
Improvements in or connected with the Working and Welding
of Metals by Electricity.
I. ALFRED LONGSDON, of 9 New Broad Street in the City of London, Civil
Engineer, do hereby declare the nature of this invention (a communication to
me from abroad by the firm of Fried Krupp, of Essen in the Empire of Germany,
Cast Steel Manufacturers) and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement :-
This invention refers to improvements on an 'invention for which a Patent was
granted in England dated 28 October 1885 No. 12984, wherein the electric arc is
formed between the work as one pole and a carbon or pencil of suitable material as
the other pole.
In using the electric arc in this method, variations in its length and consequently
in its resistance, down to zero, for generating the arc, cannot be avoided. The
consequence of the self-excitation of the shunt-wound machines is, that considerable
variations of the pressure take place at the terminals or clamps. The reflex actions
of said variations upon the electric are disturb the latter to such an extent
that working with the same is very troublesome and must be interrupted at
intervals.
Attempts have been made to obviate this disadvantage by means of accumulators
or storage batteries, which are coupled up in parallel with the continuous current
dynamo. The storage battery acts so to speak as a buffer to take up the violent
current-shocks occurring with this method, but storage batteries have the
disadvantage of constantly requiring very careful attention; their first cost and
expense of maintenance are very high, and they require a great deal of space.
According to this invention I substitute for the storage batteries hitherto
employed an arrangement of the external exciting circuit of dynamos as hereafter
described and obtain a perfect substitute for storage batteries with respect to
maintaining constant the pressure or tension at the terminals.
The invention will be fully understood by further describing same with reference
to the accompanying diagram.
The continuous current dynamo B employed for supplying current for the electric
arc A, does not itself excite its electro-magnets (limbs) C, but the latter are
excited or energized from a second source of current supply D, in conjunction with
a regulating resistance E.
.
As the exciting source of current supply there may be employed a battery of
primary, secondary, or thermal elements or cells, or a continuous current dynamo.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
In the working and welding of metals by electricity, the combination of two
sources of current-supply, one of which serves to energize the magnetic field of
that source, the effective current of which is employed for heating and welding,
and substantially as hereinbefore set forth.
BREWER & SON,
London and Leeds, Agents for Applicant.
TO Con WOOT ST RAT