Improvements in Regulating Transformers for Alternating Currents.
Year: 1895

page_text: ....
Date of Application, 8th Apr., 1895-Accepted, 1st June, 1895
COMPLETE SPECIFICATION.
Improvements in Regulating Transformers for Alternating Currents.
MANCHESTER EDISON SWAN Co. LTD. Engineers Temple Chambers
Brazennose Street Manchester and ALFRED STILL Civil Engineer Bow Green
Farm Bowdon Cheshire and EDWARD WOODROWE COWAN Civil Engineer
Vicarage Lane Bowdon, 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 :-
The object of our invention is to obtain in an improved manner a transformer
which will give a variable ratio of transformation of electromotive force, the ratio
being altered by a mechanical movement of a part of the apparatus either by hand
or automatically.
The improvement consists in a special design whereby extreme compactness
and simplicity of construction with high efficiency is obtained.
The improved regulating transformer may be applied to the regulation of the
electromotive force in the feeder circuits of a system of electric supply whereby
with the generator or generators supplying electricity at a constant electromotive
force the electromotive force of each of the feeders supplied by the generator or
generators can by means of this improved apparatus be adjusted so that the
electromotive force at the feeding centre can be kept constant at all loads. The
apparatus being placed at any part of the feeder circuit. The improved regulating
transformer can also be applied to an ordinary transformer or generator for the
purpose of compensating for "drop" in electromotive force between open circuit
and full load. To effect this purpose the secondary coil of the regulating
transformer would be placed in series with the circuit in which the "drop
occurred, the primary & moveable coil being moved either by hand or
automatically.
"
The improved regulating transformer can be applied to any purpose whatever
where a regulating transformer serves a useful purpose.
We effect the object of our invention in the following way :-
"
In the accompanying drawing Fig. Is is the secondary and p is the primary.
The secondary is wound in recesses or tunnels in a laminated iron core having a
ring shape, the coils either encircling the core as shewn on the drawing, this form
of winding being generally known as the "gramme or they are wound upon the
inner face of the ring in the form generally known as "drum" winding. The
primary is wound upon a shuttle shaped laminated iron core. The primary core
being mounted on a shaft preferably made of non-magnetic metal which can rotate
while the secondary core remains fixed.
The action is as follows:-
In Fig. I the primary coil with its core is shewn in the position of maximum
ffect. Magnetism induced by the current in the primary coil follows approxi-
mately the path shewn by the dotted lines D D. thus threading the secondary coils
& generating electro motive force in them. The secondary coils are so wound that
half the added electromotive force is generated in the left hand coil & half in the
right hand coil. The connections are so made that these electromotive forces are
added to each other.
In Fig. II the primary coil with its core is shewn in the position of no effect.
The magnetism induced by the current in the primary coil follows approximately
the path shewn by the dotted lines D D threading half the secondary coils in one

page_text: direction and half in the opposite direction, the added electromotive force being
balanced by the subtracted electromotive force the resultant effect being nil.
In intermediate positions of the primary coil between those shewn in Figs. I
and I respectively, intermediate effects are obtained between these two extremes.
If the primary coil be rotated beyond the position of no effect in Fig. II
electromotive force will be generated in the secondary coils in an opposite sense or
subtracted instead of added.
↑
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim.is:
1. The construction of a regulating transformer in which a variable ratio of
transformation is obtained by a mechanical movement of the primary coil whereby
though the magnetic flux is practically constant for all positions of the primary
coil and the secondary coils are cut by practically the same number of lines per
second in all positions, the portion of the secondary coils cut in a positive sense by
the magnetic lines to those cut in a negative sense is variable according to the
position of the primary coil relatively to the position of the secondary coils.
II. The construction of a regulating transformer having its primary coil wound
upon an iron core substantially of the design shewn on the accompanying drawing
in conjunction with its secondary coils wound upon an iron core substantially of the
design shewn on the same drawing.
III. The application of the improved regulating transformer to:-
(a.) The regulation of alternating current feeder or other circuits.
(b.) The regulation of the secondary electromotive force of an ordinary
alternating current transformer whereby secondary "drop" is compensated
for.
(c.) The raising and lowering of lights for scenic and other effects.
(d.) Any purpose whatever where a regulating transformer serves a useful
purpose.
Dated this 5th day of April 1895.