IMPROVEMENTS IN ELECTRIC GOVERNORS
Year: 1884

page_text: COMPLETE SPECIFICATION.
We, ANDREW JAMIESON C.E., F.R.S.E., Principal of The Glasgow College of
Science and Arts, Glasgow, in the County of Lanark, North Britain, and STEPHEN
ALLEY, of The Sentinel Works, Polmadie, in the County of Renfrew, North
Britain, Engineer, do hereby declare the nature of our said invention for
"IMPROVEMENTS IN ELECTRIC GOVERNORS" and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:-
Our said Invention has for its object to provide apparatus whereby the action
of a combined motor and dynamo-electric machine may be automatically governed
or regulated notwithstanding variations produced accidentally or otherwise in the
resistance to, or work to be done by the electric current generated. Thus for
example, if the dynamo-electric machine is used for actuating a number of
incandescent lights arranged in multiple arc, our improved electric governor will
bring about a suitable adjustment of the throttle valve of the steam engine or of
the equivalent part of any other motor, whenever the action of one or more of the
lights is stopped or renewed.
In carrying out the Invention a disk of metal and by preference of copper, made
to rotate by the motor, is placed so that its outer part moves through a magnetic
field or fields induced by one or more electro magnets excited by means of coils of
insulated conducting wire which forms a shunt to the main circuit from the
dynamo-electric machine. The same shunt circuit may be that which is used to
excite, or to assist in exciting the field magnets of the dynamo-electric machine ;
or it may be a separate or distinct shunt circuit used only for exciting the governor
magnets. The governor disk is connected to the shaft or spindle which carries
and turns it by a volute spring or other suitable spring, and in rotating it
experiences resistance in passing between the poles or pole pieces of the governor
magnets. When one or more of the lights are stopped the strength of the current
passing through the shunt circuit becomes increased and by intensifying the
magnetic field increases the resistance to the rotation of the disk, and this resistance
is additionally increased because of an increase which simultaneously takes place
in the speed of the motor. The increased resistance causes a relative movement
between the disk and its shaft and this movement is by suitable mechanism made
to bring about the adjustment of the throttle valve or equivalent part of the

page_text: .
motor. When the action of one or more of the lights is renewed the strength of
current through the shunt, circuit and the rotatory velocity of the disk become
diminished so as to lessen the resistance to the disk's rotation; and the volute
spring then causes a reversed relative movement of the disk which brings about
the readjustment of the throttle valve or equivalent part of the motor.
Whilst the improved governor is extremely simple in its construction and action,
it has the important practical advantages, that in its operation there are no changes
of electric contacts for putting resistances into circuit or for taking out resistances
or for other purposes; and that there are no sliding or frictional contacts through
which electric currents have to pass.
And in order that our said Invention and the manner of performing the same
may be properly understood we hereunto append two sheets of explanatory
drawings to be hereinafter referred to and representing our improved electric
governor.
Figure, 1, on sheet, 1, of the accompanying drawings is a plan of the governor,
figure, 2; on sheet, 2, is a sectional elevation, and figure, 3, is a longitudinal vertical
section. In these drawings the same reference letters are used to mark the same
or like parts wherever they are repeated.
The governor is carried on a base plate, B, having fixed on it standard bearings, b1,
which carry a horizontal shaft or spindle, a, having fast on it a pulley, P, for
receiving a driving cord from the steain engine or other motor. The pulley, P, is
shown as made with two grooves of different diameters, and it might be made
with more of such grooves, to suit different ratios of speed between the governor
and the driving pulley of the motor. A copper disk, D, made with a thickened
rim is fixed to a brass centre, C, which is made with a boss fitted loosely on the
shaft, s. The centre, C, is also made with a rim, 7, on one side of it forming a
shallow circular box in which there is placed a volute spring, V, having its centre
or inner end fixed, like that of a watch spring, to the shaft, 8, whilst its outer
end is fixed to the rim, r, of the disc, centre, C. The outer side of the volute
spring, V, is covered by a small disk, d, and a collar, c, fixed on the shaft, 8, after
the disk centre, C, is in place, prevents this centre from moving along the shaft.
The boss of the disk centre, C, has a screw thread formed on it to work in an
internal screw formed in the end of a sleeve or tube, t, which is fitted loosely on
the shaft, 8, and can move along it, whilst it is made to turn with it by screws, K,
acting as keys in longitudinal grooves formed in the shaft. Additional grooves
are provided at suitable parts round the shaft to facilitate the adjustment of the
parts. The tube, t, is made with bevil surfaces, 7, to act as frictional bevil wheels;
and to engage with one or other of them there is arranged a frictional bevil
wheel, L, on a vertical spindle, W, carried in bearings, 62, 63, and formed with a
worm or tangent screw, w, which gears with a toothed sector, Q, fixed on a rocking
shaft, R. When the tube, t, is in its middle position neither of its bevil surfaces, 7,
is in contact with the bevil wheel, L; but when from an alteration taking place
in the resistance experienced by the disk, D, the disk centre, C, moves faster or
slower than the shaft, 8, then the screwed boss of the disk centre, C, causes the
tube, t, to move along the shaft, 8, and to put one or other of its bevil surfaces, 7,
into contact with the bevil wheel, L; and on this occurring the bevil wheel, L, is
turned with its shaft W, and the worm, w, acts on the sector, Q, and through it
moves the rocking shaft, R. The rocking shaft R, is carried in bearings of which
one, 64, is shown and may be connected in any convenient way to the throttle
valve or equivalent part of the motor..
Two pairs of electro-magnetic poles, M, are arranged to act on the copper
disk, D, being placed with their pole pieces N, S, N, S, at diametrically opposite
positions at about the level of the shaft, 8. The cores of the magnets, M, with the
bottom connecting pieces, m of the two pairs, are fixed by screws to the base
plate, B, and the pole pieces, N, S, N, S, are bolted to the tops of the magnet cores,
and are placed with their inner ends or faces very near to but not touching the
copper disk, D, adjusting screws, as, being provided for setting them at suitable

page_text: distances from the disk. The insulated wire for conducting the shunt current for
exciting the electro-magnets, M, is coiled on the cores in the usual way being
continued from one pole to another in succession, and having its ends, T + and T
connected in any suitable manner to the dynamo-electric machine.
-
It is obvious that the details of the apparatus may be considerably modified to
suit different circumstances and requirements. The difference in the current
through the shunt circuit does not itself directly shift the throttle valve or
equivalent part of the motor; but it simply effects an adjustment of the governor
details requiring little force, in consequence of which adjustment the power
communicated from the motor to the governor is made to effect the adjustment of
the throttle valve or equivalent part; and with this arrangement the governor is
made much more sensitive than it could otherwise be. The rocking shaft, R, may
itself directly shift the throttle valve or equivalent part or it may be arranged to
move the valve of a steam cylinder or the like which will shift the throttle valve
or equivalent part.
Having thus particularly described the nature of our said Invention and in
what manner the same is to be performed we proceed to ascertain the distinctive
features of novelty thereof by declaring that what we claim is:-
J
The arranging or combining together of parts to form an electric governor
substantially in the improved manner hereinbefore described; and more particularly
the arranging of a copper or other suitable metallic disk to rotate between magnetic
poles excited by the electric current in a shunt circuit from the dynamo-electric
machine, the changes in the resistance to the disk's rotation and produced by
changes in the current and in the rotatory velocity being made to bring about the
required adjustments of the throttle valve or equivalent part of the motor.
Dated this fifth day of February 1884