IMPROVEMENTS IN APPARATUS FOR REGULATING THE SPEED OF ENGINES USED FOR DRIVING DYNAMO-MACHINES FOR ELECTRIC- LIGHTING AND OTHER PURPOSES
Year: 1883

page_text: LETTERS PATENT to Peter William Willans of Thames Ditton in the County
of Surrey for an Invention of "IMPROVEMENTS IN APPARATUS FOR REGULATING
THE SPEED OF ENGINES USED FOR DRIVING DYNAMO-MACHINES FOR ELECTRIC-
LIGHTING AND OTHER PURPOSES
"
.
"
PROVISIONAL SPECIFICATION left by the said Peter, William Willans at
the Office of the Commissioners of Patents on the 5th March 1883.
PETER WILLIAM WILLANS of Thames Ditton in the County of Surrey
IMPROVEMENTS IN APPARATUS FOR REGULATING THE SPEED OF ENGINES USED
FOR DRIVING DYNAMO-MACHINES FOR ELECTRIC LIGHTING AND OTHER PURPOSES
"
This invention has for its object the better regulation of the speed of engines
driving dynamo machines so as in the case of electric lighting to ensure as far as
possible the maintenance of a constant current. in the lamps independent of the
number of lamps burning, or of the pressure of steam, or of other outside causes.
I employ a solenoid or equivalent electrical arrangement through the coils of
which either a part, or it may be the whole of the current from the machine
passes.
+
I so arrange this solenoid that its iron core is acted on by two forces, in the
one direction by the current tending to draw the core further into the coils as
it increases in strength and in the other direction by a spring acting to draw
the core further out of the coils when from any cause the current becomes weaker
as for instance if the steam pressure falls or more lamps are connected.
I so adjust the apparatus that any where within certain limits in the position of
the core a given current-viz the current I desire to maintain balances as nearly as
may be the pull on the core caused by the opposing spring, i.e. with this strength
of current the core of the solenoid may be moved within certain limits without
affecting the balance of forces, and it will remain wherever it may be placed.
I so arrange the throttle valve or expansion valve that the movement of the core

page_text: of this solenoid causes an increase or diminution of the steam supplied to the
engine
The core of the solenoid actuates a small piston or other valve which supplies.
water, steam or other fluid under pressure to a cylinder in which a piston,
connected by suitable mechanism with the throttle valve or expansion valve works.
I prefer to employ a piston valve for this purpose because of the small power
required to work it and the consequently greater delicacy of the action of the
current on it but other forms of valve way in some cases be used.
The piston working the throttle valve and the valve worked by the solenoid are
so arranged with relation to each other that when the piston working the throttle
valve moves its motion compensates for the movement of the piston valve caused
by the action of the core of the solenoid upon it.
The above result may be attained in one way, by placing. the small piston valve
inside the piston working the throttle or expansion valve.
Figure 1 shews such an arrangement. A. A are the coils of the solenoid. B the
iron core connected by the rod R with the piston valve P working inside the
piston P¹ which works in the cylinder X. The hollow piston rods N and N' pass
through the ends of the cylinder X and the hollow piston rod N' is connected by
the rod F with the throttle or expansion valve of the engine.,
The piston P¹ has an annular space round it M into which water or other fluid
pressure is admitted by the pipe S. By a suitable passage G the annular space M
communicates with an annular space between the two pistons forming the piston
valve P.
A passage K leads from the lower piston of the piston valve P to the upper end
of the cylinder X.
ל
A similar passage K¹ leads from the upper piston of the piston-valve P to the
lower end of the cylinder X.
:
The core B of the solenoid is lifted and drawn further into the coils when the
current is increased in strength, when the current is weakened the spring C acting
upon it in the other direction draws it out again.
The action is as follows.
In the position shewn the current is supposed to be constant and the mechanism
is at rest. If the current be increased the piston valve P is lifted by the core of
the solenoid. Pressure is admitted to the bottom of the piston P¹ by the passage K₁
which is uncovered by the upper piston of the piston valve. The water or other
fluid above the piston escaping by the passage K and the hollow, piston rod N¹.
This causes the piston P¹ to rise and, as it rises it closes the throttle valve by
means of the rod F at the same time weakening the current by reducing the speed
of engine and stopping the motion of the core B. The piston P¹ continues to rise
until the passages K and K', are closed when the mechanism is again ät rest. If
the current is weakened the action is reversed.
In cases where lamps are arranged in parallel circuit the solenoid may take the
place of the lamp or lamps on one of the bridges between the main wires.
In cases where the lights are arranged in series or in cases where the current is
used for any purpose in which it is desired to maintain a constant strength of
current against varying resistances the whole of the current may be taken through
the coil of the solenoid.
+

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
·
by the said Peter William Willans in the Great Seal Patent Office on the
5th September 1883.
"
PETER WILLIAM WILLANS of Thames Ditton in the County of Surrey:
"IMPROVEMENTS IN APPARATUS FOR REGULATING THE SPEED OF ENGINES USED
FOR DRIVING DYNAMO MACHINES FOR ELECTRIC LIGHTING AND OTHER PURPOSES
This invention has for its object the better regulation of the speed of engines
driving dynamo machines so as in the case of electric lighting to ensure as far as
possible the maintenance of a constant current in the lamps independent of the
number of lamps burning or of the pressure of steam or of other outside causes.
I
I employ a solenoid or equivalent electrical arrangement through the coils of
which either a part, or it may be the whole, of the current from the machine
passes.
I so arrange this solenoid that its iron core is acted on by two forces, in the
one direction by the current, tending to draw the core further into the coils as
it increases in strength and in the other direction by a spring acting to draw
the core further out of the coils when from any cause the current becomes weaker
as for instance if the steam pressure falls or more lamps are connected.
The core of the solenoid I connect to a piston or other valve which I cause to
control the supply of water, steam or other fluid under pressure to a cylinder in
which works a piston connected by suitable mechanism with the throttle valve or
expansion valve of the engine so that the movement of the core of the solenoid
causes an increase or diminution of the steam supplied to the engine.
I prefer to employ a piston valve for this purpose because of the small power
required to work it and the consequently greater delicacy of the action of the
current upon it but other forms of valve may in some cases be used.
Preferably also I arrange the mechanism in such manner that the piston working
the throttle valve and the valve worked by the solenoid are so arranged in relation
to each other that when the piston working the throttle valve moves, its motion
compensates for the movement of the piston valve caused by the action of the core
of the solenoid upon it, that is, that into whatever position the valve may be moved
the piston follows it and comes to rest when it overtakes the valve.
The above result may be attained in one way, by placing the small piston valve
inside the piston working the throttle or expansion valve.
I so adjust the apparatus that at any point within certain limits of the travel of
the core a given current i.e. the current I desire to maintain balances to a sufficient
extent the pull on the core. caused by the opposing spring so that with a given
strength of current the core may be moved through the above mentioned length of
travel without materially affecting the balance of forces but as an exact balance
throughout the whole travel is difficult to arrive at and is not absolutely
necessary I prefer so to arrange the strength of the spring in relation to the
current that with the desired strength of currents the core has a tendency to come
to rest at the centre of its travel rather than in any other position-I prefer to
employ that part of the travel of the core in which the greater part is exterior to
the helix and in which the pull (with a constant current) strengthens as the core is
drawn further into the coils as in this case it can be conveniently balanced by a
spiral or other form of spring-but in cases where it may be desirable to use the
inner portion of the travel i.e. the portion in which the greater part of the core is
within the coils and in which the pull strengthens as the core is drawn outwards.
I employ an arrangement of compensating lever and weight so as to obtain the
above described balance of forces.
17.
J
F

page_text: In cases where the electrical arrangement takes the form of an electro magnet in
place of a solenoid, a magnet of the form known as a horse shoc magnet may be
used. In this case I suspend the armature of the electro magnet by links in such
manner that it may be made to traverse through a comparatively long stroke in a
direction transverse to the axes of the core of the magnet.
7
At Figure 1 I have shewn one way in which the apparatus may advantageously'
be constructed.
1
:
A A are the coils of the solenoid. B the iron core connected by the rod R with
ther piston valve. P.working, inside the piston P' which works in the cylinder, X.
The hollow, piston rods N and N pass through the ends of the cylinder X and the
hollow: piston rod. N' is connected by the rod F with the throttle or expansion;
gear of the engine as for example to the quadrant of the ordinary link motion.
The piston' P¹ has an annular space round it M into which water or other fluid
pressure is admitted by the pipe. S. By a suitable passage G the annular space M
communicates with an annular space between the two pistons forming the piston
valve P.
A passage K leads from the lower piston of the piston valve P to the upper end
of the cylinder X.
A similar passage K₁ leads from the upper piston of the piston valve P to the
lower end of the cylinder X.
The core B of the solenoid is lifted and drawn further into the coils when the
current is increased in strength, when the current is weakened the spring C acting
upon it in the other direction draws it out again. If the apparatus is set vertically
the weight of. the iron core and piston valve may be balanced by a balance weight
as shown. If the apparatus is placed horizontally this balance weight will not be
required.
The action is as follows:- :
In the position. shewn the current is supposed to be constant and the mechanism
is at rest. If the current be increased the piston valve P is lifted by the core of
the solenoid. Pressure is admitted to the bottom of the piston P¹ by the
passage K¹ which is uncovered by the upper piston of the piston valve.
The water or other fluid above the piston escaping by the passage K and tho
hollow piston rod N¹. This causes the piston P¹ to rise and as it rises it closes the
throttle valve by means of the rod F at the same time weakening the current by
reducing the speed of engine and stopping the motion of the core B. The piston Pl
continues to rise until the passages K and K' are closed when the mechanism is
again at rest. If the current is weakened the action is reversed.
Another way of attaining the same result is to connect the piston working throttle
valve and the core of the solenoid and the piston valve to different points in a bar.
Figure 2 shews an arrangement.of this kind
A A are the coils of the solenoid, B the iron core connected by the rod R to the
bar X. C is the spring. To this bar is connected the piston valve P. This bar X
is jointed at another point to the rod S which connects the piston P¹ to the throttle
valve T of the engine. This throttle valve is shown as a piston working in a
cylinder and so arranged that as it moves it covers or uncovers holes in the side of
the cylinder and 'so admits less or more steam to the engine..
+
When the spring overpowers the current and the piston valve P is raised by the
rod R water or fluid pressure is admitted from the pipe c by passage K to the
upper side of the piston P₁ and the throttle valve T is opened. When the current
overpowers the spring and the valve P is lowered the fluid pressure passes in like
manner by passage K¹ to the underside of piston Pl and the throttle valve T closes.
As the rod S moves it moves the bar ✗ with it and consequently the piston
valve P until by its motion it has closed the passages K K' leading to the cylinder
in which the piston P¹ works, when'tlie mechanism is at rest.
The weight W balances the weight of core B, rod R and piston valve P
The way in which the inner portion of the travel of the core of a solenoid may
be made use of is shewn in Figure 3.

page_text: A is the core of the solenoid C the coils of the same-L' is a lever arm to
which the core A and the rod of a piston or other valve is connected. L is
another arm of the same lever carrying a weight W. The lever L L¹ turns on a
fixed centre at F.
Figure 3 shows the core of the solenoid in such a position that with a given
current, the pull or tendency of the core to be drawn further into the coils,
decreases until it becomes nothing when the centre of core coincides with centre
of coils and reaches its maximum when the core is about half inside and half
outside the coils.
.
The weight W acting through levers L L' balances the pull on the core A in the
position shewn in Figure 3.
When A is further out and the pull greater the weight W will have greater
effect when core A is further in and pull less, weight W will have less effect.
Figure 4 shows how an electro magnet may be used in place of the solenoid.
A is an electro magnet B its armature carried by links C. D is a rod passing to
a piston or other valve-E is a spring acting in opposition to the pull of the
magnet
In cases where lamps are arranged in parallel circuit the solenoid or electro
magnet may take the place of the lamp or lamps on one of the bridges between
the main conductors and this bridge need not necessarily be between points in
the main conductors in or near the engine room but the conductors may be tapped
if desired at very distant points and thus maintain a constant current in the bridge
and hence a constant difference of potential between the conductors at these distant
points.
In cases where the lights are arranged in series or in cases where the current is
used for any purpose for which it is desirable to maintain a constant strength of
current against varying resistances the whole of the currents may be taken through
the coils of the solenoid.
Having thus described the nature of my invention and the manner of performing
the same I would have it understood that I claim-
First, The combination of a solenoid or electro magnet with a valve arranged
to control the supply of water or other fluid to the opposite ends of a cylinder in
which is a piston coupled to the throttle valve or expansion gear of the steam
engine employed for driving the dynamo electric machine used for producing the
current substantially as described.
Second. The combination of a solenoid or electro magnet with a valve arranged
to control the supply of water or other fluid to the opposite ends of a cylinder in
which is a piston coupled to the throttle valve or expansion gear of the steam
engine employed for driving the dynamo electric machine used for producing the
current and in which the piston follows the valve and comes to rest when it
overtakes the valve substantially as described.
Third. The combinations of apparatus substantially as herein before described
and illustrated in the Drawings annexed.
In witness whereof I the said Peter William Willans have hereunto set my hand
and seal this 29th day of August in the year of our Lord One thousand eight
hundred and eighty three.
P W WILLANS (L.S.)