Improvements in Rotary Transformers.
Year: 1899

page_text: Date of Application, 1st June, 1899-Accepted, 1st June, 1900
COMPLETE SPECIFICATION.
Improvements in Rotary Transformers.
I, JOHN MCLEOD MURPHY, of Torrington, in the County of Litchfield and State
of Connecticut, United States of America, Electrician, 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:-
:-
This invention relates to improvements in that class of motor transformers
designed to furnish a given source of energy at a high potential from a storage
battery of low potential, and in which the ratio of windings are theoretically of
such differences as to compensate for the mechanical and electrical losses in the
apparatus.
This kind of apparatus, it is understood, is good only for transforming in one
direction for the reason were it attempted to operate the same in reverse direc-
tions, .e., make the high potential side, which was the generator, become the
motor, and the low potential, which was formerly a motor, a generator, it is
evident that the ratio of transformation will be considerably less, owing to
armature reaction, mechanical and other losses, and if it were desired to charge
the storage battery such operation would be impossible, owing to the electro-
motive force being insufficient to counteract the then high counter electro-motive
force of the said battery.
The purpose of this invention is to provide a rotary transformer apparatus
having means whereby sufficient electro-motive force can be obtained at the low
potential armature to charge the battery when an electro-motive force is applied
to the high potential armature, equal to that which it (the high potential arma-
ture) generated when rotated by the current supplied from said battery to low
potential armature; the high potential armature will then become a motor to
drive a low potential armature under such conditions as to charge the storage
battery which originally gave the low potential armature motion. This result I
obtain by means of an auxiliary winding, the special arrangement and operation
of which, in combination with the regular field windings, I shall now explain
in detail and set out in the claims, reference being had to the accompanying
drawing, in which:―
Fig. 1 illustrates, diagrammatically, the general arrangement of a rotary
transformer constructed in accordance with my invention; and,
Figs. 2 and 3 illustrate modified arrangements of the same, hereinafter parti-
cularly referred to.
In the drawing, SB indicates the storage battery current to field windings A B
and low potential, armature C, of such proportion and strength that the high
potential armature D will generate a desired electro-motive force.
Assuming the SB to have 20 volts electro-motive force and driving armature C,
at such speed that with a given field excitation in B, the high potential arma-
ture D, mechanically connected with the armature C, will generate, say 500 volts.
Now, it is evident that if 500 volts were applied to armature D, in opposite
directions, very little current will pass, the two electro-motive forces being nearly
equal and opposed neutralizing one another.

page_text: To create an electro-motive force when the high potential current is applied
in a reverse direction, sufficiently in excess to the initial or battery force, I
provide an auxiliary winding F, which is put in series with armature D, and
wound on the same core as field A, and in such direction that it will produce a
magnetisation in the same direction as field A, to increase the magnetic force of
such field and correspondingly the electro-motive force of armature C, which
armature, by reason of its increased electro-motive force produced by the auxiliary
magnetising force from the high potential circuit through the winding F, will
gradually take less and less current from battery S B, and at the same time cause
armature D, to take current through the applied 500 volts or high potential
circuit which increased current, going through the winding F, will still further
increase the electro-motive force of the armature Cuntil it becomes sufficient
to charge storage batteries SB.
Instead of putting the auxiliary winding about core A, the same may be
placed around core B, as shown in Fig. 2; in this case, however, the direction
of the winding must be such that the resultant magnetism is opposed to wind-
ing B, to diminish its magnetic force and cause a reduced counter electro-
motive force in armature D, which will enable it to take circuit from the applied
500 volts sufficient to rotate both armatures C-D, at a higher speed, whereby
to cause armature C to produce a higher electro-motive force sufficient to charge
the storage batteries, it being also manifest that the two methods above described
may be combined as in Fig. 3, to accomplish the same results. In this case two
auxiliary windings F-F, are provided, which are properly wound and directed
on the respective cores A-B to produce the results desired. The auxiliary
winding is, of course, only connected with the circuit when the transformer is
used to charge the storage battery, i.e. when transforming down.
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. A rotary transformer of the character described, having means for effecting
sufficient change in the magnetising force under an applied electro-motive force
of high potential in inverse direction, whereby to cause the low potential arma-
ture to generate a voltage greater than that supplied from the battery for the
purposes specified.
2. In a rotary transformer of the character stated, an auxiliary winding for
the field cores in circuit with the high potential armature for the purposes
specified.
3. A rotary transformer, having a supplemental winding in circuit with the
high potential armature for creating a change in the magnetising force for the
fields when an applied electro-motive force of higher voltage than the initial
force for rotating the low potential armature is directed in inverse direction
through the high potential armature, as specified.
Dated this 1st day of June 1899
BOULT & WADE,
Agents for the Applicant.