IMPROVEMENTS IN INDUCTION COILS
Year: 1884

page_text: I, JAMES SWINBURNE of 41 Manor Road, St. John's in the County of Kent,
Electrician, do hereby declare the nature of said invention for "IMPROVEMENTS
IN INDUCTION COILS" to be. as follows:→
My invention has for its object improvements in induction coils mainly for
distribution of electrical energy. In an induction coil according to my invention
wherein an alternating current is to bo used in the primary, coil, I dispenso with
the iron core heretofore usually employed and .mix the wires of the primary and
secondary coils together. Thus a coil or bundle of cable of two or more strands
may be used, some of the strands being employed for the primary circuit and others
for the secondary, there being no magnetic core.
For direct currents the same arrangement may be employed with or without a
magnétic core but I make the current either intermittent in the primary circuit or
alternating by the 'uso of a circuit breaker or commutator. This may be for
instance a commutator driven by a small motor whose speed is governed by the
electro motivo force on the terminals of the secondary circuit, so that, for instance
several of these machines may be placed in series, each feeding a varying number
of incandescent lamps, preserving uniform electro-motive force on their terminals,
and absorbing power in proportion to the number of lamps used, in spite of
variations of electro-motive force or current available in primary circuit.
A self regulating dynamo which gives either a uniform or a suitably varying
current may be used. I may commutate the main current in parts or by
instalments so as to avoid sparking which might be troublesome.

page_text: I JAMES SWINBURNE of 41 Manor Road St. John's in the county of Kent,
Electrician, do hereby declare the nature of my invention for IMPROVEMENTS
IN INDUCTION COILS and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
My invention has for its object improvements in induction coils mainly for
distribution of electrical energy. In an induction coil according to my invention
wherein au alternating current is to be used in the primary coil I dispense with the
iron core heretofore usually employed & mix the wires of the primary & secondary
coils together. Thus a coil or bundle of cable of two or more insulated strands
may be used, some of the strands being employed for the primary circuit & others
for the secondary, there being no magnetic core. Thus a coil may be made of a
cable consisting of ten fine wires wound round one thick one. An alternating
current of high tension can now be led by very small leads from a great distance,
& passed through the ten snall wires in series. The thick wire may now be
connected to glowlamps in parallel, & will render to them a certain percentage of
the energy yielded by the high tension current.
For direct currents I use the same arrangement but I commutate the primary
current by means of a commutator driven by an electromotor. The electromotor
is driven by the main or secondary current & rotates a commutator with brushes
like a dynamo commutator. As this commutator deals with high tension currents
it is advisable that it should not commutate the whole of the primary circuit nt
once, but each length of wire may be done separately so as to avoid sparking. The
electromotive force on the secondary circuit may be kept uniform by making any
variation alter the speed of the motor. Thus a small brake may be applied to the
motor by a solenoid or electromagnet actuated by the secondary current in shunt
to the lamps, so that an increase of electromotive force makes the motor go slower.
Several coils may be arranged in series on the same primary circuit, and with
governors as described, they will preserve uniform electromotive force on whatever
number of lamps may be in use, whether the driving engine or dynamo are
governed or not.
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. An induction coil for electric lighting without a core of iron or other magnetic
material.
2. An induction coil wherein the primary current is commutated.
3. An induction coil wheroin the primary curront is commutated in sections
substantially as set forth.
4. An induction coil wherein the electromotive force of the secondary circuit is
controlled by acting on the speed of commutating.
Dated this 9th day of October 1884,