IMPROVEMENTS IN THE MEANS OR APPARATUS FOR REGULATING THE PRODUCTION OF ELECTRICITY
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by John Clayton Mewburn at the Office
of the Commissioners of Patents on the 28th June 1882. Communicated to
him from abroad by Fernand Rigaud of Paris Franco
JOHN CLAYTON MEWBURN of 169 Fleet Street in the City of London, Patent
Agent and Consulting Engineer "IMPROVEMENTS IN THE MEANS OR APPARATUS
FOR REGULATING THE PRODUCTION OF ELECTRICITY Communicated to him
from abroad by Fernand Rigaud of Paris France.
23
In the distribution of electricity it is important to obtain constancy of the
current notwithstanding variations in the number of apparatus actuated by the
current, either by maintaining constant the difference of potential at the two
extremities of the circuit, or by preserving in the current itself the same intensity,
according to the arrangement of the apparatus in relation to the general-circuit,
in derivation or in tension
Various proposals have already be made to obtain this constancy of the current
but they have objections they modify the speed of the engine which works the
electric generator.
By means of the present invention the speed of the engine is kept constant
and the electrical condition of the machine which generates the current is never
modified. The invention consists in principle in modifying the speed of the
electric generator according to the state of the current so as to keep constant the
difference of potential or the intensity of the current, and this without changing
the speed of the engine. This result is obtained automatically by apparatus which
acts upon the parts which transmit the motion; this modifies, according to
circumstances in the one sense or the other, the relation of the speeds of the engine
and of the dynamo machine or other electric generator.
The Invention can be carried out in various ways some of which I will now
explain.
In a mechanical point of view the transmission of the motion can be effected by
means of a disc driven by the engine and producing by frictional contact the
rotation of a roller koyed on the shaft of the electric generator, and movable along
this shaft; the position of the roller on its shaft is controlled by the electric
current so that it approaches the centro of the disc when the current increases

page_text: and moves away from the centre when the current diminishes. Or the transmission
can be effected by means of a strap passing over two cones on parallel axes and of
the same angle and pointing in opposite directions; the fork of the strap is
controlled by the electric current so as to move the strap towards the apex of the
driving cone when the current increases and away from it when the current
diminishes. Other arrangements such as a spherical roller running on a revolving
surface properly calculated may also be adopted.
As regards the electrical means for altering the position of the roller, fork, or
other device as above mentioned, it can be arranged on two distinct bases. The
electrical agent can be required to produce a displacement calculated so that it
restores the relative speed to a suitable point; this method requires special
calculation for each particular case. Or the current may be required to cause a
throwing of parts into and out of gear when it varies and to keep them in this
position until the relative speed has become what it ought to be. This method is
quite general; it requires very little electric power, and in this point of view it
appears preferable; I will therefore refer to it further.
According to one arrangement for carrying it into effect, the fork, roller, or
other device is controlled by a rack worked by a pinion keyed on a shaft which is
common to two bevel wheels; a third wheel on a shaft at right angles to the other
shaft rotates between them. This second shaft passes through a bearing which is
kept in equilibrium between a spring or counterweight and an electro magnet.
This electro magnet is traversed either through a short wire by the whole of the
current when it is wished to maintain the intensity constant (apparatus in tension)
or by a derivation through a long fine wire when it is wished to maintain the
potential constant (apparatus in derivation). The spring being adjusted for the
normal state, if the current increases the bearing is attracted and the rotating
whicel is moved into gear with one of the other two wheels and the rack is moved,
thereby slackening the speed of the electric generator until the current falls a
little below the normal state; the spring then draws back the bearing, the rotating
wheel moves out of gear while the rack preserves its position. A decrease of the
current on the other hand allows the spring to pull the rotating wheel into gear
with the other of the two wheels so that the rack is moved in the opposite
direction. Stops limit the displacement to the minimum quantity necessary and
it is well to cover these stops with caoutchouc to avoid shocks. Except when there
are great alterations in the circuit the parts are in a state of equilibrium and the
slightest variations of current will be translated into a slight displacement of the
rack in the proper direction.
The above arrangement which is given as an example is capable of being varied
without departing from the principle. For instance the intermediate parts can be
simplified by substituting for the rack a rod placed between two rollers turning in
the same direction, contact with the ono or the other of them being produced by
the action of an electro magnet. Or the electric contact can bo controlled by a
ball governor turning under tho action of a small electric machine whoso current is
taken from the whole circuit (in derivation or in tension) and the variations of whose
speed produce the movement of the hall, and the contact of the bevel wheel on
the one side or the other. Or instead of moving the single level wheel by tho
action of the letra amagat as for described the magnet can be made to move
the two bevel wheel, which are on the other shaft.