A New or Improved Continuous Current Transformer and Method of Winding the Field Magnets of such.
Year: 1892

page_text: Date of Application, 9th Jan., 1892
Complete Specification Left, 10th Oct., 1892-Accepted, 12th Nov., 1892
PROVISIONAL SPECIFICATION.
A New or Improved Continuous Current Transformer and Method
of Winding the Field Magnets of such.
We FRANCIS MURRAY NEWTON and TOM HAWKINS both of The Newton
Electrical Engineering Works, Taunton, Electrical Engineers, do hereby declare
the nature of this invention to be as follows:-
Our invention relates to a new or improved dynamotor or continuous current
transformer, which is designed to yield a current of constant electro-motive force at
the secondary terminals of the transformer or at any given point in the external
secondary circuit and this notwithstanding variations of the load. Our invention
also embraces a method of winding the field magnets of dynamotors.
In our invention we employ as is usual a high tension armature and a low tension
armature rigidly attached to one another and each with its own field magnet. The
Baid field magnets are compound wound. The series winding of the primary field
magnet is in series with the primary armature, the external primary circuit and the
generator. The series winding of the secondary field magnet is in series with the
secondary armature, the external secondary circuit and the lamps or other
apparatus for which the current is supplied. The shunt winding is common to both
magnetic circuits, that is to say a coil constituting either the whole or a part of
the shunt winding embraces a part of each field magnet, instead of first embracing a
part of one field magnet and then a part of the other. The said shunt winding is
derived from the secondary circuit.
The action is as follows. When the current in the primary circuit is turned on
the primary or motor armature as is well known begins to rotate and so drives or
causes rotation of the secondary or dynamo armature. The current generated by
the revolution of this armature passes through the shunt winding and increases the
magnetisation of the primary field. The series winding of the primary field magnet
is now cut out of circuit either by a hand switch or by an automatic device. Both field
magnets are now excited by the shunt winding but as current is taken from the
external secondary circuit the magnetisation of the secondary field by its series
winding is increased so as to compensate for the loss of volts which would otherwise
take place in the said secondary circuit.
F
.
1
1000
uay
F. M. NEWTON,
TOM HAWKINS,
Per J. G. Lorrain, M. Inst. E.E., M. Inst. M.E., &c.,
Norfolk House, Norfolk Street, Strand, London, W.C.,
Applicants' Patent Agent.
COMPLETE SPECIFICATION.
A New or Improved Continuous Current Transformer and Method
of Winding the Field Magnets of such.
We, FRANCIS MURRAY NEWTON, and TOM HAWKINS, both of The Newton
Electrical Engineering Works, Taunton, Electrical Engineers, 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 :-
Our invention relates to a new or improved dynamotor or continuous current
transformer which is designed to yield a current of constant electro-motive force at
the secondary terminals of the transformer or at any given point in the external
Price 8d.]

page_text: secondary circuit, and this notwithstanding variations of the load. Our invention
also embraces a method of winding the field magnets of dynamotors.
In the accompanying sheets of drawings, Figure 1 is a side elevation partly in
section, Figure 2 an end elevation and Figure 3 a plan of a dynamotor or continuous.
current transformer constructed under our invention. Figures 4 and 5 are diagrams
illustrating the principles of our invention, the former figure being of the nature of
a side elevation in so far as it relates to the dynamotor and of the nature of an end
elevation in so far as it relates to a generator shown as used in conjunction with the
said dynamotor; whilst Figure 5 is of the nature of a plan section.
The said diagrams (Figures 4 and 5) illustrate more especially the action of our
invention and also that part of our invention which relates to the method of winding
the field magnets.
In our invention we employ as is usual a high tension armature B and a low
tension armature B₁ rigidly attached or nearly so to one another, and each with its
own field magnet (A and A¹). The said field magnets are compound wound, the
series winding C of the primary field magnet A is in series with the primary
armature B, the external primary circuit X and the generator Y. The series
winding C of the secondary field magnet A is in series with the secondary
armature B¹ the external secondary circuit Z and the lamps or other apparatus L
for which the current is supplied.
The shunt winding D is common to both magnetic circuits (that is to say a coil
constituting either the whole or a part of the shunt winding embraces a part of
each field magnet instead of first embracing a part of one field magnet and then a
part of the other) and as usual is derived from the secondary circuit Z. In order
that the adjacent limbs of the separate field magnets may be embraced in this
manner we prefer to make that part of their limbs so embraced integral, that is to
say the metal of the two limbs is not divided so as to have the limbs actually distinct
at such part as is covered by the secondary winding. Although however we prefer
to make such part integral we may have the limbs actually separate, in which case
we provide such part of the limbs with lateral extensions, so that they may meet
and be in actual contact with one another. This latter arrangement is diagram-
matically illustrated in Figure 3. In this figure a a are the lateral extensions to
which we have referred. When we adopt the plan of having the part of the field
magnets embraced by the secondary coil integral, we find it convenient to make
such part integral with the bed plate, forming in fact part of the same casting.
When we adopt this plan, we generally attach the upper parts or pole pieces of the
field magnets to the said integral parts by means of bolts as shown in Figures 1, 2
and 3. In this case it is convenient to put the primary windings over the said lower
parts of the said attached pole pieces as shown in Figures 1 and 2.
The action of our invention is as follows. When the current in the primary
circuit is turned on, the primary or motor armature, as is well known begins to
rotate and so drives or causes rotation of the secondary or dynamo armature. The
current generated by the revolution of this armature passes through the shunt
winding and increases the magnetisation of the primary field.
The series winding
of the primary field magnet is now cut out of circuit either by a hand switch or by
an automatic device. Both field magnets are now excited by the shunt winding but
as current is taken from the external secondary circuit, the magnetisation of the
secondary field by its series winding is increased so as to compensate for the loss of
volts which would otherwise take place in the said secondary circuit.
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 new or improved continuous current transformer substantially as set
forth.
2. The new or improved method of winding the field magnets of continuous
current transformers substantially as and for the purpose set forth.

page_text: 3. In continuous current transformers of the kind specified in Claim 1, the
integral construction of field magnet limbs substantially as set forth with reference
to Figures 1, 2, and 3.
4. In continuous current transformers of the kind specified in Claim 1, the
5 construction of field magnet limbs set forth with reference to Figure 3A.
Dhin Tanah 1
Otaha 1000
J. G. LORRAIN, M. Inst. E.E., M. Inst. M.E.,
Norfolk House, Norfolk Street, Strand, London, W.C.,
Chartered Patent Agent.