Improvements in and relating to the Governing of Engines used for Driving Electric Generators in Electric Distributing Systems.
Year: 1899

page_text: Date of Application, 11th May, 1899
Complete Specification Left, 12th Feb., 1900-Accepted, 14th Apr., 1900
PROVISIONAL SPECIFICATION.
Improvements in and relating to the Governing of Engines used for
Driving Electric Generators in Electric Distributing Systems.
I, HENRY ALEXANDER MAVOR, of 47, King Street, Mile End, Glasgow, in the
County of Lanark, Engineer, do hereby declare the nature of this invention to be
as follows:-
In electrical distributing systems in which dynamos are driven by steam
engines, it has heretofore been usual to govern each engine for constant speed
at all loads and to compensate for the fall in voltage of the dynamo either by
means of a hand regulated shunt resistance, or by the use of compound or over-
compound winding on the field magnets of the dynamo. Both of these methods
of governing are however objectionable in practice as the engine is kept running
at the same speed through all variations of load, and the economy of working is
not good at the lighter loads. With the object of attaining a better economy,
attempts have been made to vary the speed of the engine in direct proportion
to the load and for this purpose a solenoid arrangement has been directly applied
to the throttle valve of the engine in such a way that variation in the voltage
of the dynamo circuit varied the pull on the solenoid and thus operated the
throttle valve of the engine. Such attempts, however, have failed owing to the
arrangements adopted having produced what is known as "hunting" of the
governor.
Now according to this invention the speed of an engine driving a dynamo
is varied in proportion to the load by the action of an auxiliary centrifugal
governor that controls the supply of motive fluid to the engine and is driven by
a variable speed rotary electric motor supplied with current from the dynamo
circuit. By this means variations in the E.M.F. of the dynamo will immediately
produce corresponding variations in the speed of the electric motor and governor
whereby the supply of motive fluid and consequently the speed of the engine,
will be quickly varied in proportion to the load. It is found in practice that the
variations thus obtained are more dead beat" in their action than those obtain-
able with a solenoid which has a comparatively great inertia.
**
My improved method of governing may be applied in connection with motive
fluid engines of various kinds including steam, oil and gas engines, turbines
and water wheels.
In one arrangement according to this invention, the auxiliary centrifugal
governor is applied to the throttle valve or expansion valve of a steam engine
the position of which valve will be suitably varied by variation in the speed of
the electric motor and governor consequent upon variation in E.M.F. of the
circuit of the dynamo driven by the engine. The centrifugal governor, which is
preferably made as light as possible and to run say at 1500 revolutions a minute
and may be of any well known or suitable high speed type is mounted on the
spindle of the electric motor which should be of sufficient power to give a positive
motion and overcome all friction due to glands etc. The power of the motor will

page_text: depend upon the size of the engine but in any case should be large enough to
give a certain and positive action for every change of speed. In conjunction with
this governor mechanism, an ordinary or main centrifugal governor is provided,
such governor being set so as to prevent racing of the engine when the auxiliary
governor is not in operation.
In another arrangement, the auxiliary governor and electric motor are con-
nected to the adjusting spring of the main governor lever mechanism so that the
speed of the engine will be automatically increased to compensate for the drop in
E.M.F. due to the armature reactions and resistance losses in the dynamo. In
one arrangement of this kind, the range of adjustment can be limited by the
action of stops on the adjusting lever that is controlled by the auxiliary governor,
so that the variation in speed of the engine brought about by the auxiliary
governing device may be limited to any desired amount. For example, the main
governor may be set so that the engine will run at 400 revolutions per minute.
Usually the range of speed which can be brought about by hand adjustment is
about 100 revolutions per minute, and the range of speed change effected by the
electric motor may be limited to the same amount by the action of two fixed
stops acting upon one or other side of the link or lever through which the motor
driven governor automatically performs this operation.
This arrangement of governing apparatus is similar to that first herein referred
to except that the electric motor is applied to the adjusting mechanism of the main
governor through the adjusting spring and does not impart positive motion to the
throttle valve or expansion gear.
The electric motor in each arrangement follows by its variations in speed, the
variations in the E.M.F. of the dynamo circuit, and increases or decreases the
steam admission, directly in the first arrangement, and by changing the adjust-
ment of the main governor in the second arrangement.
. in
111
1
1000
Improvements in and relating to the Governing of Engines used for
Driving Electric Generators in Electric Distributing Systems.
I, HENRY ALEXANDER MAVOR, of 47, King Street, Mile End, Glasgow, in the
County of Lanark, 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:-
In électrical distributing systems in which dynamos are driven by steam
engines, it has heretofore been usual to govern each engine for constant speed
at all loads and to compensate for the fall in voltage of the dynamo either by
means of a hand regulated shunt resistance, or by the use of compound or over-
compound winding on the field magnets of the dynamo. Both of these methods
of governing are however objectionable in practice as the engine is kept running
at the same speed through all variations of load, and the economy of working is
not good at the lighter loads. With the object of attaining a better economy,
attempts have been made to. vary the speed of the engine in direct proportion
to the load and for this purpose a solenoid arrangement has been directly applied
to the throttle valve of the engine in such a way that variation in the voltage

page_text: of the dynamo circuit varied the pull on the solenoid and thus operated the
throttle valve of the engine. Such attempts, however, have failed owing to the
arrangements adopted having produced what is known as "hunting
governor.
of the
Now according to this invention the speed of an engine driving a dynamo
is varied in proportion to the load by the action of an auxiliary centrifugal
governor that controls the supply of motive fluid to the engine and is driven by
a variable speed rotary electric motor supplied with current from the dynamo
circuit. By this means variations in the E.M.F. of the dynamo will immediately
produce corresponding variations in the speed of the electric motor and auxiliary
governor whereby the supply of motive fluid and consequently the speed of the
engine, will be quickly varied in proportion to the load. It is found in practice
that the variations thus obtained are more dead beat" in their action than
those obtainable with a solenoid which has a comparatively great inertia.
The improved method of governing may be applied in connection with motive
fluid engines of various kinds including steam, oil and gas engines, turbines
and water wheels.
Fig. 1 shows, diagrammatically, one arrangement of governing means accord-
ing to this invention.
at m.
a a represents the centrifugal balls of a main governor which is rotated by a
shaft from the engine whose speed is to be regulated and which drives the
dynamo d. The balls a are connected together by a spring e and are carried by
rods that are pivoted at g and act through arms upon the endways movable
sleeve or rod which is connected to one end of a throttle valve lever pivoted
n, n, represent the centrifugal balls of the auxiliary governor which is
rotated by the shaft o from the electric motor p which is connected by leads
to the circuit of the dynamo d. The balls n are connected together by a spring s
and carried by rods t that are pivoted at u and act through arms upon the main
governor sleeve or rod k. The auxiliary governor n, which is preferably made
as light as possible and to run say at 1500 revolutions a minute, may be of any
well known or suitable high speed type. The electric motor p should be of
sufficient power to give a positive motion and overcome all friction of the parts
to which it is connected. The power of this motor will depend upon the size of
the engine c to be controlled, but in any case should be large enough to give a
certain and positive action for every change of speed. w is a throttle valve con-
nected to the lever and having its seat at, the said valve controlling the supply.
of motive fluid from the pipe y to the pipe leading to the engine c.
1 is an
adjusting spring connected to the throttle valve lever 7 and provided with a hand
wheel 2 whereby the load exerted on the said lever by the spring can be adjusted.
3 is a stop fixed to the engine framing to limit the extension of the spring 1, and
consequently the strain put upon it. The spring and stop must be so relatively
arranged as not to interfere with the closing of the valve in.
The centrifugal pull of the main governor a is so adjusted that when at its
maximum, which occurs when the speeds of the said governor and of the engine
have attained the highest limit permissible, it will close the throttle valve w
against the pull of the springs e, s and 1, so that the speed of the engine will be
controlled when there is no current on the motor driving the auxiliary
governor n.
The arrangement of the apparatus shown in Fig. 1 is such that on closing the
circuit of the dynamo d, the electric motor p will start running and as soon as
it and the auxiliary governor reach the desired speed, which is proportional
to the desired electromotive force of the dynamo, the auxiliary governor will
assist the mechanically driven governor a to control the throttle valve Thus
when the EM F of the dynamo rises beyond the desired amount, the auxiliary
governor will act to close the throttle valve w and so reduce the speed of the
engine c and dynamo d. When the load on the dynamo increases, the electro-
motive force tends to fall and also the speed of the electric motor p. so that the

page_text: auxiliary governor will then act to assist the mechanically driven main governor a
to open the throttle valve w..
Fig. 2 shows diagrammatically a modified arrangement wherein the auxiliary
governor n is connected by a rod 4 to the adjusting spring 1 connected to the
main governor lever mechanism so that as the EM F of the dynamo d rises
beyond the normal and the speed of the electric motor p consequently increases
the said auxiliary governor n will reduce the tension of the spring 1 and allow
the throttle valve w to be closed by the main governor, and when the E M F of
the dynamo falls below the normal and the speed of the motor is consequently
reduced, the auxiliary governor n will pull on the said spring 1 and assist the
main governor to open. the throttle valve so as to increase the speed of the
engine and thereby raise the EMF of the dynamo to the normal amount. The
range of the adjustment and motion of the spring 1 may be limited by the action
of two adjustable but normally fixed stops 3 and 3 which limit the movement of
projections 1 and 1b on the spring so as to prevent over extension of the spring
either by the adjusting serew, or by the auxiliary governor, the said stops being
so arranged that they will not prevent either the opening or closing of the valve.
By suitable adjustment of the spring 1 between the strips 3, 3ª, and of the strength
of the springs e, s and 1, the amount of variation in the speed of the engine e can
be limited to any desired amount. For example, the main governor can be
set so that the engine will run at say 400 revolutions per minute. Usually the
range of speed which can be brought about by hand adjustment is about
100 revolutions per minute, and the range of speed change effected by the electric
motor can be limited to the same amount by the action of the two stops 3, 3ª.
is
As will be seen the modified arrangement of governing apparatus shown in
Fig. 2 is similar to that shown in Fig. 1 except that the electric motor
applied to the adjusting mechanism of the main governor a through the adjusting
spring 1 and does not impart positive motion to the throttle valve c.
The electric motor in each arrangement follows by its variations in speed, the
variations in the E.M.F. of the dynamo circuit, and thereby increases or decreases
the steam admission, directly in the first arrangement, and by changing the
adjustment of the main governor in the second arrangement.
The apparatus instead of controlling a throttle valve may in like manner con-
trol an expansion valve.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is:-
-
1. Varying the speed of an engine driving a dynamo in proportion to the load
on the dynamo by the action of an auxiliary centrifugal governor that controls
the supply of motive fluid to the engine and is driven by a variable speed rotary
electric motor supplied with current from the dynamo circuit, substantially as
herein before described.
2. In apparatus for governing the speed of an engine driving a dynamo, the
combination with a main governor driven from the engine and adapted to pre-
vent racing thereof, and a valve connected to said governor and adapted to con-
trol the supply of motive fluid to the engine, of an auxiliary governor driven by
a variable speed rotary electric motor supplied with current from the dynamo
circuit, the said auxiliary governor being arranged to directly assist the main
governor in controlling the position of the said valve in accordance with the load
on the dynamo, substantially as herein before described with reference to Fig. 1
of the accompanying drawings.
3. Apparatus for governing the speed of an engine driving a dynamo wherein
an auxiliary governor driven by a variable speed rotary electric motor supplied
with current from the dynamo, is connected to the adjusting spring of the main
governor lever mechanism that controls the valve governing the supply of motive
fluid to the engine, the arrangement being such that variations in the speed of the

page_text: electric motor due to variations in the load on the dynamo, will vary the action
of the said adjusting spring and indirectly assist the main governor to open and
close the said valve, substantially as described.
4. For governing engines driving electric generators in electric distributing
systems, apparatus constructed arranged and operating substantially as herein
before described with reference to and shown in Fig. 1, and in Fig. 2 of the
drawings annexed.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C., Chartered Patent Agent.