Year: 1899

page_text: I, BENJAMIN GARVER LAMME, of 230, Stratford Avenue, Pittsburgh, in the
County of Allegheny and State of Pennsylvania, U.S.A., Electrical Engineer, do
hereby declare the nature of this invention to be as follows:-
1
My invention relates to systems of electrical distribution in which current is
supplied to translating devices through a transformer, and has for its object to
provide an arrangement for varying the electromotive force supplied to such
translating devices.
In installations of this kind where a large amount of energy is being employed
variation of the secondary electromotive force of the transformer is a difficult
matter because of the high electromotive force or heavy currents which are in-
volved and which render the use of switching devices for varying the active length
of either primary or secondary winding of the transformer neither economical
nor safe
According to my present invention I provide a third coil on the transformer
which supplies an additional electromotive force to the translating devices through
a second transformer; the length of this third coil can be varied and it is so de-
signed and proportioned as to have a range of electromotive force equal to the
maximum variation desired in the electromotive force supplied to the translating
devices. Since this is usually only a comparatively small per centage of the
whole electromotive force supplied to such devices the regulation may be readily
effected without injuring the switching devices used.
In the accompanying drawing I have shewn a diagram of a system of distri-
bution comprising an alternating current generator 1, a step-down stationary
transformer 2, the primary of which is in circuit with said generator 1, and
translating devices 4 supplied with current from the secondary winding 5 of the
transformer 2.
In order to vary the electromotive force supplied to the translating devices, as
is often found necessary in practice, I provide a third coil 6 from which leads 7
are carried out to contact pieces 8. One terminal of the third coil 6 is connected
to a switch arm 9 arranged to make contact with any one of the stationary
contact pieces 8, in order to vary the active length of the third coil 6. This
winding 6 is so proportioned as to have generated therein a comparatively small
current and low electromotive force such as will not interfere with the operation
.
77

page_text: of the switching devices 8, 9. In order that the variation of the electromotive
force of this third coil may be imparted to the circuit supplying the translating
devices, I provide a series transformer 10, one winding 11 of which is in circuit
with the secondary 5 of the transformer 2, and 'the other winding in series with
the third coil 6, or with such portion of the same as may be in circuit through the
switching devices 8, 9. It will be readily seen that with this arrangement of
apparatus the third coil may be designed and proportioned to have a range equal
to the maximum variation in the secondary electromotive force desired, and this
is ordinarily only a comparatively small per centage of the entire secondary
electromotive force, the regulation may be readily effected without injury to the
switching devices employed.
I have, for convenience, shewn the invention as applied to a single phase circuit
but it will be understood that it is equally applicable to circuits of two or more
phases, and it will also be understood that the translating devices supplied with
current from the transformer 2 may be of any known type or kind and connected
in circuit in any well known manner.
1000
I, BENJAMIN GARVER LAMME, of 230, Stratford Avenue, Pittsburgh, in the
County of Allegheny and State of Pennsylvania, U.S.A., Electrical Engineer, 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:
My invention relates to systems of electrical distribution in which current is
supplied to translating devices through a transformer, and has for its object to
provide an arrangement for varying the electro-motive force supplied to such
translating devices.
In installations of this kind where a large amount of energy is being employed
variation of the secondary electromotive force of the transformer is a difficult
matter because of the high electro-motive force or heavy currents which are in-
volved and which render the use of switching devices for varying the active
length of either primary or secondary winding of the transformer neither
economical nor safe.
According to my present invention I provide a third coil on the transformer
which supplies an additional electro-motive force to the translating devices
through a second transformer, the length of this third coil can be varied and it is
so designed and proportioned as to have a range of electro-motive force equal to
the maximum variation desired in the electro-motive force supplied to the trans-
lating devices. Since this is usually only a comparatively small percentage of
the whole electro-motive force supplied to such devices the regulation may be
readily effected without injuring the switching devices used.
In the drawing filed with the Provisional Specification I have shewn a diagram
of a system of distribution comprising an alternating current generator 1, a step-
down stationary transformer 2, the primary 3 of which is in circuit with said
generator 1, and translating devices 4 supplied with current from the secondary
winding 5 of the transformer 2.
In order to vary the electro-motive force supplied to the translating devices, as

page_text: is often found necessary in practice, I provide a third coil 6 from which leads 7
are carried out to contact pieces 8. One terminal of the third coil 6 is connected
to a switch arm 9 arranged to make contact with any one of the stationary contact
pieces 8, in order to vary the active length of the third coil 6. This winding 6
is so proportioned as to have generated therein a comparatively small current, and
low electro-motive force such as will not interfere with the operation of the
switching devices S. 9. In order that the variation of the electro-motive force
of this third coil may be imparted to the circuit supplying the translating devices,
I provide a series transformer 10, one winding 11 of which is in circuit with the
secondary 5 of the transformer 2, and the other winding in series with the third
coil 6, or with such portion of the same as may be in circuit through the switching
devices 8, 9. It will be readily seen that with this arrangement of apparatus the
third coil may be designed and proportioned to have a range equal to the maximum
variation in the secondary electro-motive force desired, and this is ordinarily only
a comparatively small percentage of the entire secondary electro-motive force,
the regulation may be readily effected without injury to the switching devices
emploved.
I have, for convenience, shewn the invention as applied to a single-phase circuit,
but it will be understood that it is equally applicable to circuits of two or more
phases, and it will also be understood that the translating devices supplied with
current from the transformer 2 may be of any known type or kind and connected
in circuit in any well known manner.
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. The method of regulating the electro-motive force supplied to translating
devices in the secondary circuit of a transformer by means of a third coil on the
transformer, which third coil is connected to one coil of a second transformer,
the other coil of which is in the circuit containing the translating devices.
2. An electrical installation in which for the purpose of varying the electro-
motive force in the secondary circuit of a transformer a third coil is provided on
the transformer with means for varying its active length, said third coil being
connected to one coil of a second transformer, the other coil of which is in the
circuit containing the translating devices.
3. A. system of electrical distribution substantially as described with reference
to the accompanying drawings.
Dated the 18th day of April 1900
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester and Birmingham.