An Automatic Compensating Feed Electric Arc Lamp.
Year: 1889

page_text: Date of Application, 6th May, 1889-Accepted, 15th June, 1889
COMPLETE SPECIFICATION.
An Automatic Compensating Feed Electric Arc Lamp.
We, ALFRED UPTON ALCOOK of Corr's Lane in the City of Melbourne and Colony
of Victoria, Electrical Engineer, and HENRI GALOPIN of Temple Court Place,
Melbourne, Scientific Engineer, do hereby declare the nature of this invention, and
in what manner the sume is to be performed, to be particularly described and ascer-
tained in and by the following statement :-
This Invention of an automatic compensating feed electric arc lamp has been
designed to produce an are lamp composed of few moving parts and having, 1st. an
automatic feed device which imparts a practically continuous feed to the upper
carbon, such device being controlled by the electric current; and 2nd. an autoniatic
compensating balance for the upper carbon This lamp my either be arranged for
running in series or in parallel. The accompanying drawings illustrate two forms of
series lamp uz: differential and shunt.
In the differential lamp the feed device is located under the solenoid and upon the
end of a hollow soft iron core which is within the solenoid and through which core
the upper carbon supporting har passes. When the regulating coil is arranged as a
shunt only, then the feed device is securod upon the top of the soft iron core and
above the solenoid. Such fied device consists of a grip or friction pawl or clutch
between which and a rigid jaw the upper carbon supporting bar passes The pawl is
caused to release its grip of the bar when a pin or device attached to the pawl
makes contact with a rigid part of the lamp frame. This action takes place when the
upper carbon is being fed down.
The automatic compensating balance is constructed by suspending the upper carbon
supporting bar by a cord wire or other flexible support from a small barrel having
attached to its side a fusce from which is suspended (in an opposite direction to the
carbon bar cord) a balance of the requisite weight. As alternatives for the fusee
its cord and weight, a spiral spring may be combined with the barrel or a coiled
spring with its one end secured to a cord attached to the barrel and its other end
secured to the lamp frame.
In the accompanying drawings :-
Figs 1 and 2 shews views partly in section of the differential lamp taken at right
angles to one another, the lower frame work and carbons being omitted in Fig. 2.
Fig 3 is a plan looking upwards from the line a a in Fig 2, drawn to a larger
scale and cxhibiting the pawl or clutch mechanism
Fig 4 is a side view of Fig 3, and
Fig. 5 is a diagram of the differential lamp
Figs 6 and 7 are views at right angles to one another of the working parts of the
alternative construction of larp, and
Figs 8, 9 and 10 are enlarged details of its grip clutch and the compensating
balance.
In Figs 1 to 5 A is the sclenoid A' the lamp frame and P and N the terminals of
the lamp; B is the soft iron core having at its end the rigid block B' and the
pivoted pawl or clutch B the latter having an extended side arm B3 which is
arranged to stike a rigid bar Ax of the lamp frame; The arm B is furnished with
an adjustable weight B. C is the upper carbon supporting bar, and D the upper
carbon;
E is a counterbalance lever furnished with an adjustable weight E¹ and
having its inner bow end attached by pins to the core B; E is a sway support for
the lever E F is a brush forming a connection between the frame A¹ and the rod C;
Gis the lower carbon and H is the lower frame-work of the lamp; 1 is the cut out,
the purpose of which is to serve as a by-passage for the current through the lamp
shou'd the carbons be burnt out or any accident happen to the lamp mechanism
The

page_text: cut out consists of the resistance I¹ equal to arc, an electro-magnet I' and an
armature 1. The upper end of the rod C is attached by a flex.ble connection to a
small barrel J arranged and secured on the same spindle as a fusee J¹ the spindle
being supported at the upper end of the lamp frame A². The fusee J' supports by
another flexible connection a balance weight J and this weight acting upon the
variable diameter of the fusee at all times, counterbalances the weight of the upper
carbon D and also imparts a constant strain on the clutch feed device from the time
the lamp commences to burn until the carbon has burnt out.
In Figs. 6 to 10 which shew the shunt lamp, parts marked by letters herein before
referred to represent similar or corresponding parts. The clutch feed device and
the cut out being differently arranged will now be described. The pawl or cam B
has a pin B projecting from its side and under the pin there is arranged another
pawl B centred on a small bracket seated upon the solenoid A The lever E is
centred upon an arm extension from the solenoid, its outer end passing to under the
cut out I; the armature l' in this lamp is arranged upon and insulated from the
lever E and is connected to the resistance I' whose other end is connected to
the terminal N. K is a tension spring acting upon the lever E, and K' a screw hook
for adjusting the tension.
The course of the several currents in the lamp shewn in Figs. 1 to 4 will be best
understood by describing same with reference to diagram Fig. 5 in which the thick
wire is the main current and the fine wire c the shunt while the arrows indicate the
direction of the currents. Now, assuming the carbons to be in contact and no are
consequently existing the current entering at P will pass along the main wire b,
thence to the brush F, to the upper carbon D, and from the upper to the lower
carbon G, thence to the main wire b (or frame work H), through the solenoid and on
to the main wire leading to the terminal N. The shunt circuit or fine wire is
connected across from terminal to terminal and is of a suitably high resistance, say
about 180 to 200 ohms; the shunt current enters at P and passes through the
cut out therce around main solenoid in a reverse direction to it, and with a
considerably greater number of tuins, and thence out by the terminal N. Another
course for the main current is from P through the cut out and thence through the
wire leading to terminal N.
The action of the lamp is as follows -The current from P passes through the
carbons and thence through the main coil, which will then suck in the soft iron core
the clutch of which raises the upper carbon bar and its carbon so as to form the arc,
which, assuming the current to be constant, will take up a definite length.
The are having taken up this position will now continue burning until its length
will have slightly increased, causing a greater difference of potential at the terminals
and consequently a greater flow through the shunt thereby decreasing the power of
the main coil which consequently gradually lowers the clutch device, causing the arm
projecting from pawl to rest slightly on the lamp frame; this releases the carbon
holder bai and allows it to pass through until the arc has again assumed its normal
length. This cycle of actions is repeated until the carbons are burnt out.
The action of the cut out is as follows:-Suppose the iron core were to stick, or
the carbon holder bar to have fed its whole length, the are would then gradually
increase in length until an extra sti ong current would pass through the shunt coil
which also passes around the cut out and so increases the power of the electro-magnet
to attract the armature and short circuit the lamp. The current would then flow
through the re-istance and through the thick wire coil of the electro-magnet which
would then retain the armature so long as a current is passing. Again, if the iron
core were released and so allow the carbons to come together, then the currents would
divide and the electro-magnet would now become too weak to retun the armature
when the whole current would follow the original course, and the lamp would become
agun lighted
The action of the lamp shewn in Fig. 6 to 10 when it is switched into circuit is as
follows The current will take its course through the shunt coil A which sucks the
iron core B in, and causes the pin B5 on the pawl B² to engage with the pawl B,

page_text: when the latter, pressing under the pin B³, causes the pawl B' to rise, and allows the
upper carbon rod C to descend, until the two carbons come together. The contact of
the carbons will short circuit the shunt coil and allow the counterbalanced laver E and
the tension spring K to lift iron core B, and with it the rod C which is now clutched
between the grip jaws B1 and B2, and so the carbons are retuned at a sufficient
distance apart to form the arc. As the arc lengthens its resistance will increase and
so cause a greater flow through coil A, which in turn, sucking in the iron core B
until the pin B again bears on the pawl B, opens pawl B' to allow the rod C to
gradually descend until the arc is restored to its normal length.
Having now particularly described and ascertained the nature of our said Inven-
tion and in what manner the same is to be performed, we declare that what we
claim is
-
(1) In an electric arc lamp; an automatic clutch feed device for regulating the
descent of the upper carbon; constructed arranged and operated substantially as
herein before described with reference to the accompanying drawings
(2) In an electric arc lamp; an automatic compensating balance for the upper
carbon; constructed arranged and operated substantially as hereinbefore described
with reference to the accompanying drawings.
Dated this 2nd day of May A.D. 1889.
WILLIAM E. HEYS,
Agent for the Applicants.