Improved Means for Controlling the Supply of Electric Current to Electric Mains from a Dynamo or Dynamos.
Year: 1890

page_text: Date of Application, 9th Dec., 1890
Complete Specification Left, 9th Sept., 1891-Accepted, 24th Oct.. 1891
PROVISIONAL SPECIFICATION.
Improved Means for Controlling the Supply of Electric Current to
Electric Mains from a Dynamo or Dynamos.
I, PETER WILLIAM WILLANS of Ferry Works, Thames Ditton in the County
of Surrey, Engineer, do hereby declare the nature of this invention to be as
follows:-
For controlling the potential at any desired point or points in electric mains used
for conveying electric current from a dynamo or dynamos, I lead off branch con-
ductors from such mains at the place where it is required to maintain a constant or
approximately constant difference of potential between the conductors of the
main. These branch conductors I lead to the terminals of a small electric motor
located in proximity to the engine by which the supplying dynamo is driven.
small electric motor is capable of being driven in either direction. In the branch
circuit I also introduce some constant source of electric current to act in opposition
to the current derived from the main conductors. A small dynamo run at constant
speed or secondary batteries may be used for the purpose.
The
When the current passing from the main balances the constant current the small
electric motor will remain at rest. When the current from the main varies froin
the constant current. the axis of the small motor will be revolved in one or other
direction according to whichever current preponderates, and may be caused to act
upon the throttle valve or expansion gear of the engine by which the dynamo used
for supplying current to the mains is driven or may be caused to put a shunt
resistance in or out of the circuit producing the magnetic field of the dynamo or to
alter the forces which act on the throttle valve or other gear, it may be by shifting
a weight along a lever arm in connection with the valve or in other suitable
way. In large systems where the mains are fed with current at a number of points
in the circuit the potential in the mains may be controlled in the same way at each
such point.
The controlling mechanism may be used for controlling all of the dynamos where
a number are used or it may be used for controlling only one or more of such
number as desired.
11
ليم
1
1
1000
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Dated this 8th day of December
1000
COMPLETE SPECIFICATION.
Improved Means for Controlling the Supply of Electric Current to
Electric Mains from a Dynamo or Dynamos.
I, PETER WILLIAM WILLANS of Ferry Works, Thames Ditton in the County
of Surrey, 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 :-
For controlling the potential at any desired point or points in electric mains used
for conveying electric current from a dynamo or dynamos, I lead off branch con-
ductors from such mains at the place where it is required to maintain a constant or
approximately constant difference of potential between the conductors of the main.
These branch conductors I lead to the terminals of a small electric motor located
The small
in proximity to the engine by which the supplying dynamo is driven.
electric motor is capable of being driven in either direction.
In the branch circuit
I also introduce some constant source of electric current to act in opposition to the

page_text: current derived from the main conductors. A small dynamo run at constant speed
or secondary batteries may be used for the purpose.
When the potential difference to be kept constant balances the potential difference
of the small electric motor, this motor will remain at rest. When the potential
difference in the main varies from the constant potential difference the armature of
the small motor will be revolved in one or other direction according to whichever
potential difference preponderates, and may be caused to act upon the throttle valve
or expansion gear of the engine by which the dynamo used for supplying current to
the mains is driven or may be caused to put a shunt resistance in or out of the
circuit producing the magnetic field of the dynamo or to alter the forces which act
on the throttle valve or other gear, it may be by shifting a weight along a lever
arm in connection with the valve or in other suitable way. In large systems where
the mains are fed with current at a number of points in the circuit the potential in
the mains may be controlled in the same way at each such point.
The controlling mechanism may be used for controlling all of the dynamos where
a number are used or it may be used for controlling only one or more of such
number as desired.
In order that my said invention may be fully understood and readily carried into
effect I will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure is a side elevation of a dynamo and engine and control of mechanism;
the figure illustrates diagrammatically a suitable arrangement for carrying my
invention into effect.
Figure 2 is another view of a portion of the apparatus.
D is the main dynamo for supplying current for electric lighting or other
purpose. E is the steam engine by which the dynamo is driven. M is the small
electro motor for controlling the potential in the dynamo mains.
The branch or pilot-wires and , connect the points N and P in the dynamo-
mains, between which a constant difference of potential is to be maintained, with the
terminals of the motor M. A secondary battery B so constructed or arranged as
to have between its terminals n and p, a potential difference equal to that which is
to be maintained between N and P is inserted in the lead with its poles in
opposition to the poles of the dynamo D.
Through the wires p and y a small current is led from the dynamo D through
the field coils of the motor keeping the field permanently excited whenever the
dynamo is working.
The shaft of the motor is geared by a belt or a cord to the wheel w mounted ou
the governing lever A of the steam engine E, which lever through the rod r, moves
the throttle valve of the engine.
The lever A has its fulcrum at A' T is a slider upon the lever, capable of being
traversed along it by the screw W when the same is turned by the cord passing
around the cord wheel or pulley w. U is a coiled spring attached at one end to
the slider T and at the other made fast to the bed plate of the engine or other
convenient fixture.
V is a centrifugal governor upon the crank shaft of the engine; its weighted
levers are connected with the sleeve X on the crank shaft. Y is a bell crank
lever connected with the sleeve X and also with the rod r so that as usual as the
weights are thrown outwards by centrifugal force against the resistance of springs
which control them, the throttle valve of the engine is progressively closed. The
lever A as will be seen presses upon a knife edge upon the side of the rod r and so
acts upon the governor in opposition to the centrifugal force and it acts more or
less powerfully according as the slider T is further from or nearer to the
fulcrum A'.
It will be seen that when the potential difference between N and P is equal to
that between n and p no current will pass through the armature of the motor M and
this armature therefore will remain at rest; but that, if these potential differences

page_text: differ, a current will pass through the motor armature. The arrangement is such
that when the potential difference between N and P is smaller than that
between n and p the armature of the motor will rotate so as to open the valve of the
engine further and so increase the speed and thereby the potential difference
between N and P. Whereas when the contrary is the case the current will have
the opposite direction, which will make the motor armature rotate the opposite
way, and so cause the valve to be closed and consequently the speed of the engine
to be diminished and the potential difference between N and P to fall.
It is obvious that other sources of electromotive force may be substituted for the
secondary battery B and also that the motor may be geared to the engine-governor
in a multitude of different ways. Also that I may attain the end-the regulation
of the electromotive force of the dynamo-by gearing the motor to a variable
resistance in series with the coils of the field magnets of the dynamo leaving the
engine to work at constant or nearly constant speed, regulated by the ordinary
mechanical governor only.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
The means substantially as described for controlling the supply of electric current
to electric mains from a dynamo or dynamos consisting in connecting the dynamo
leads, at points between which a certain prearranged potential difference is to be
maintained, by a shunt in which is an opposing source of current and in arranging
an electro-motor to alter the adjustment of the driving engine or dynamo when set
in motion by current passing in the shunt as herein set forth.
Dated this 8th day of September 1891.