IMPROVEMENTS IN CURRENT-GOVERNORS FOR DYNAMO-ELECTRIC MACHINES
Year: 1881

page_text: LETTERS PATENT to. Herbert John Haddan, of the firm of Herbert and
Company, Solicitors of Patents, of 67 Strand, in the City of Westminster,
Civil Engineer, for an Invention of IMPROVEMENTS IN CURRENT-GOVERNORS
FOR DYNAMO-ELECTRIC MACHINES communicated to him from abroad by
Charles F. Brush of Cleveland, State of Ohio, United States of America.
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at
the Office of the. Commissioners of Patents on the 28th April 1881.
HERBERT. JOHN HADDAN, of the Firm of Herbert and Company, Solicitors of
Patents, of 67, Strand, in the City of Westminster, Civil Engineer, IMPROVEMENTS
IN CURRENT-GOVERNORS FOR DYNAMO-ELECTRIC MACHINES a communication to
me from abroad by Charles F. Brush of Cleveland, State of Ohio United States of
Amci ica.
The invention consists in a current-governor constructed to operate in con-
nection with a dynamo-electric machine, of an electro-magnet excited by two
helices, one helix included within the main circuit and the other within a shunt-
circuit, within which said shunt-circuit is placed an adjustable resistance. Also the
combination, in an electric-current governor, of an adjustable or variable resistance
mechanism to vary said resistance, and a dash pot or equivalent, for modifying the
motion of said resistance-varying mechanism. Also in a current-governor constructed
to operate in connection with a dynamo-electric machine, of a dash pot or any equi-
valent device or mechanism that shall interpose a retarding influence or action in one
direction only Also in a current-governor constructed to operate in connection with
a dynamo-electric machine, of an arm or lever in combination, first, with an adjustable
resistance constructed to be varied through the movement of said lever; second,
with an electro-magnet, through the influence of which motion is imparted to said
arm or lever; and third, with any suitable mechanism (such as the dash-pot or its
equivalent) for governing or modifying the movements of said arm or lever-
Also in a current-governor constructed to operate in connection with a dynamo-
electric machine, of two or more resistance piles, or their equivalents, electrically
connected in series, and a device associated with each pile for varying its' electrical.
resistance.
The piles may be of carbon or other suitable material-The helices of wire one
located in the shunt circuit and the other in the main circuit.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Haddan in the Great Seal Patent Office on
the 25th October 1881.
HERBERT JOHN HADDAN of the firm of Herbert and Company, Solicitors of
Patents, of 67 Strand in the City of Westminster, Civil Engineer. IMPROVEMENTS
IN CURRENT GOVERNORS FOR DYNAMO-ELECTRIC MACHINES, a communication to me
from abroad by Charles F. Brush, of Cleveland, State of Ohio, United States of
America.
The invention relates to dynamo-electric machines, and has for its object the
adaptation of such machines to variable external conditions without variation of
the speed at which their armatures are rotated, but by variation of the intensity.
of the magnetic field, and this by means not directly depending on the volume
of current circulating in the external circuit.
I shall assume that the broad principle of shunting away a portion of the current
employed to excite the field-magnets of a dynamo-electric machine for the purpose
of weakening the magnetic field has been sufficiently well enunciated.
Figure 1 of the drawings shows modifications of and additions to old devices.
Fig 2 shows a form of apparatus wherein a pile of carbon plates, H or similar
resistance is employed in a manual apparatus. Fig 3 represents my present device
as connected and applied to a dynamo-electric machine.
In Fig 1 of the drawings, H H are piles of carbon or other suitable plates,
inclosed loosely within glass, porcelain, or other suitable insulating tubes or
supports. The piles rest upon blocks of carbon or metal electrically connected,
carried by a bar of wood or metal, which is pivoted to and supported by the
lever D. The upper ends of the insulating-tubes are loosely closed by plugs of
carbon or metal supported by the frame of the apparatus and insulated from each
other. Obviously three or more piles, H may be employed all connected in series
as are the two shown, and this is advisable when a compact apparatus of high
resistance is required. The tubes or supports inclosing the piles H may be of
metal (to absorb and radiate the heat generated) lined with mica or other
insulator.
The magnet-helix E consists of two separate coils of wire, one located in the
shunt circuit the other in the main circuit, both as shown. These two coils or
helices may be arranged in various manners in relation to each other. Either may
occupy the outer position, or may cover exclusively one line of the spool. Two
compound helices, E, with corresponding cores of iron, may be employed to increase
the effect.
Within the helix E is a movable iron core pivoted to the lever D.
This lever,
pivoted at one end as shown, also carries a movable and therefore adjustable
weight, c. (An adjustable spring may be substituted.) The free end of the lever D
also carries the body of a dash-pot If, and a thumb screw, dby which the downward
movement of the lever is adjusted. The piston of the dash-pot F is attached to
the frame-work of the apparatus by means of its rod, as shown, and is provided
with a valve opening downward. When the dash-pot is filled with glycerine or
other suitable liquid, its piston and valve allow the lever D to move downward
freely, but retard its upward movement. The valve in the piston is not essential,
but is desirable, as will be shown later.
The operation of the whole device is as follows: The binding posts pn forming
the terminals of the shunt-circuit, are connected with the field-magnets of a dynamo-
electric machine in the manner explained in the previous Letters Patent referred
tio. The course of the shunt-circuit is then from the post p through the
piles H H, outer portion of helix E, to post n. The binding posts P N are put

page_text: in the main or working circuit of the machine, as was also explained in my said
prior patent, but in such a manner that the main current shall pass through the
helix E in the same direction as the shunt-circuit. The weight c is so adjusted
that when the machine is working to its full capacity, and the normal working.
current is passing through its portion of the helix E, the inclosed iron core, lifted
by the axial magnetism developed in the helix, shall just sustain the lever D, and
parts connected therewith, while subjecting the piles H to little or no pressure.
Since in this condition of affairs the piles H H perform no function, the circuit
through them may be entirely broken by dropping the lever D sufficiently. This
however is not essential. The office of the thumb-screw d is now apparent.
If
now the resistance of the working circuit of the dynamo-machine be lessened from
any cause, the current will he correspondingly increased in the helix E, and the
enclosed core will be drawn upward, raising the lever D and subjecting the resistance-
piles H to a pressure corresponding to the increase of current in the main circuit.
Current will then be shunted from the field-magnets of the dynamo-machino until
the main current is reduced to nearly its original strength. Some increase of
current strength is however required in order to maintain a suitable pressure in the
piles H H. It is in order to render this necessary excess of main current as small
as possible that the shunted current is made to pass through a portion of the helix E.
The shunted current thus assists in maintaining a suitable pressure on the resistance-
piles H H, and the apparatus is thereby enabled to respond to very much smaller
variations in the strength of the main current than it otherwise could do. When
the carbon piles H H are subjected to pressure their conducting power increases
less rapidly than the pressure applied. Hence the apparatus is not liable to get
into the condition of "unstable equilibrium."
The office of the dash-pot F has already been described; but the function of
the valve in its piston has not been indicated. Suppose a number of voltaic-arc
lamps are operated in the main circuit, and the latter, as often occurs in practice,
becomes for an instant broken then owing to the valve in the piston-rod of the
dash-pot, the lever D drops at once, and the shunt resistance increases, so that when
the carbons in the lamps have come together and completed the main circuit again
the full power of the-dynamo-machine will be available to separate the carbons in
the lamps, and owing to the slow upward motion of the lever D allowed by the
dash pot, sufficient time is given for the carbons in the lamps to become fully
separated before the shunt can act; but if the lever D had not been allowed to fall
materially during the instant the main circuit was broken, the abnormally-great
current developed when the circuit was closed, and before the carbons in the lamps
had time to separate, would further raise the lever D and unfit the dynamo-machine
for developing its normal current. An appreciable length of time would then be
required for the resistance apparatus and the lamps tō again adjust themselves.
Again if the resistance of the main circuit is suddenly increased, the valve in the
dash-pot allows the lever D to fall at once, and thus the dynamo-machine is quickly
adapted to the new condition of circuit. Instead of the piles of carbon plates H H
other forms of resistance capable of being varied by the movement of the lever D
may be employed, also in place of the helix E, and movable core, an ordinary
electro-magnet, with fixed core & movable armature may be used, with or without
the compound helix or helices.
Fig 2 shows a method whereby a pile of carbon plates H or similar resistance
may be employed in a manual apparatus. Pressure is applied to the pile by
means of a screw actuated by the lever D, as shown. This lever moves over a
graduated circle, and acts as an index of the pressure applied to the carbon pile H,
so that a pressure suitable for a given condition of external resistance having been
once determined, it may be found again without experimenti.
A spring S may be interposed between the screw and the pile as shown, to
allow greater movement of the screw than might otherwise be admissible.
Obviously more than one pile H may be employed in this apparatus, as is done
in Fig 1

page_text: From its function in determining and governing the current evolved by a
dynamo-electric machine I will call the device herein referred to a
governor."
What I claim is :-
current-
1. In a current governor constructed to operate in connection with a dynamo-
electric machine, an electro-magnet excited by two helices, one helix included
within the main circuit and the other within a shunt circuit, within which said
shunt-circuit is placed an adjustable resistane [sic] substantially as shown.
2. The combination in an electric-current governor, of an adjustable or variable
resistance mechanism to vary said resistance, substantially as specified, and a dash-
pot, or equivalent, for modifying the motion of said resistance-varying mechanism,
substantially as shown.
3. In a current governor constructed to operate in connection with a dynamo-
electric machine as shown, a dash-pot or any equivalent device or mechanism that
shall interpose a retarding influence or action in one direction only, substantially
as shown.
4. In a current-governor constructed to operate in connection with a dynamo-
electric machine, an arm or lever D, in combination first, with an adjustable
resistance constructed to be varied through the movement of said lever; second,
with an electro-magnet, through the influence of which motion is imparted to said
arm or lever; and third, with any suitable mechanism (such as the dash-pot or its
equivalent) for governing or modifying the movements of said arm
substantially as shown.
or lever
.5. In a current-governor constructed to operate in connection with a dynamo-
electric machine, two or more resistance piles H or their equivalents, electrically
connected in series, and a device associated with each pile for varying its electrical
resistance, substantially as shown.
In witness whereof I the said Harbort John Haddan have hereunto set my hand
and seal this twentyfifth day of October A.D. 1881.
1.I
I LADYANT
LITLA TYDYA NE
MŁATYDAN