Improvements in Electrical Contact Making and Breaking Devices.
Year: 1891

page_text: Date of Application, 5th Aug., 1891
Complete Specification Left, 4th May, 1892-Accepted, 4th June, 1892
PROVISIONAL SPECIFICATION.
Improvements in Electrical Contact Making and Breaking Devices.
We CHARLES FÉRY, and EUGENE DUCRETET, both of 75 Rue Claude
Bernard, Paris, in the Republic of France, Electricians, do hereby declare the
nature of this invention to be as follows:
The object of the present invention is to enable a dynamo having a variable
speed to be employed for the charging of accumulators; this variation of speed is
found chiefly when the steam engine or other motor which drives the dynamo, acts
on several other machines which require a variable power or when the motor
employed has itself a variable speed such as a wind-mill or the like.
The contact making and breaking device is designed to cut-out or break the
circuit when the charging current interrupted firstly because at this moment the
current would be reversed rapidly and the electricity accumulated in the secondary
battery would be lost and also that the intensity of this reversed current would be
such that the collector, brushes and other parts of the dynamo would be injured or
burnt.
The improved apparatus comprises an electro magnet which gives passage to the
exciting current from the dynamo either direct or by a derivation taken at the
brushes of the dynamo. In these two cases, the attraction is proportional to
the electric tension of the dynamo. The apparatus also comprises a second coil
through which all the current of the charge passes and which is arranged to
magnetize a soft iron contact lever movable about an axis; this piece of iron is
placed inside the second coil and operates the said lever.
When the electric machine is not running the said lever is in the position in
which a spring acting to lift the outer end of the said lever maintains a contact
point on the said outer end out of contact with a cup containing mercury the upper
face of the lever resting against a stop screw.
When the dynamo is started the electric tension increases gradually until at a
certain moment, it will be equal to that of the secondary battery. At this moment
the attraction of the electro-magnet will be sufficient to overcome the tension of
the spring and to cause the contact point to dip into the mercury and to enable the
battery to be charged.
The two coils are then in action for maintaining the lever in its new position and
the charging of battery is regular.
If the speed of the conducting machine is diminishing, the current from the
dynamo will decrcase but the charging current which is passing through the second
coil will increase more rapidly and when the electro motive force of the dynamo is
equal to that of the battery, the attraction of the first coil alone (the current in
the second coil being nill) will not be sufficient to maintain the lever in its new
position and the spring will break the circuit without sparking.
The one pole of the first coil being conical the attraction of the lever will be
independent of its position; the opposite pole can also be made conical, but this is
not necessary.
One of the terminals of the second coil is always connected to the lever by means
of a contact point which is continually in contact with mercury in a cup arranged
below the same.
It will be understood that when the improved apparatus above described is used
no steel magnets are required.
For very heavy currents, in order, not to have the apparatus too large, we may
arrange a small derivation of the principal current and to control with the contact

page_text: making and breaking device an auxiliary apparatus for the greatest part of the
current.
Dated this 5th day of August 1891.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electrical Contact Making and Breaking Devices.
We, CHARLES FÉRY and EUGÈNE DUCRETET of Rue Claude Bernard 75,
Paris in the Republic of France, 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 :-
The object of the present invention is to enable a dynamo having a variable
speed to be employed for the charging of accumulators, this variation of speed is
found chiefly when the steam engine or other motor which drives the dynamo acts
on several other machines which require a variable power or when the motor
employed has itself a variable speed such as a windmill or the like.
The contact making and breaking device is designed to cut-out or break the
circuit when the charging current is interrupted because at this moment the
current would be rapidly reversed and the electricity accumulated in the secondary
battery would be lost and also that the intensity of this reversed current would be
such that the collector brushes and other parts of the dynamo would be injured
or burnt.
In the accompanying drawing we have shown how our said invention may be
conveniently and advantageously carried into practice.
The improved apparatus constructed according to our invention comprises an
electro-magnet or coil A which gives passage to the exciting current from the
dynamo Y either direct or by a derivation taken at the brushes of the dynamo. In
these two cases, the attraction is proportional to the electric tension of the dynamo.
The apparatus also comprises a second coil through which all the current of the
charge passes and which is arranged to magnetize a soft iron contact lever M M₁
moveable about an axis o, this piece of iron is placed inside the second coil B and
operates the said lever N N' which is a prolongation of lever M M'.
When the electric machine is not running the said lever N M' is in the position
shown in the drawing in which the spring R maintains a contact point t on the said
outer end, out of contact with a cup D containing mercury the upper face of the
lever resting against a stop screw t.
When the dynamo is started the electric tension increases gradually until it is
equal to that of the secondary battery. At this moment the attraction of the
electro-magnet A will be sufficient to overcome the tension of the spring R and to
cause the contact point t to dip into the mercury and so complete the circuit and
enable the battery to be charged.
The two coils are then in action for maintaining the lever in its new position and
the charging of the battery is regular.
If the speed of the conducting machine is diminished the current from the
dynamo will decrease but the charging current which is passing through the second
coil B will decrease more rapidly and when the electro motive force of the dynamo
is equal to that of the battery the attraction of the first coil A alone (the current
in the second coil B being nill) will not be sufficient to maintain the lever in its
new position and the spring R will break the circuit without sparking.
The pole C of the first coil being conical the attraction of the lever M' will be
independent of its position; the opposite pole C¹ can also be made conical but this
is not necessary the form shown being quite sufficient.
The contact point t¹ is always in contact with the mercury in a cup D¹ arranged

page_text: below the same. It will be understood that when the improved apparatus above
described is used no steel magnets are required.
For very heavy currents in order, not to have the apparatus too large, we may
arrange a small derivation of the principal current and central with the contact
making and breaking device an auxiliary apparatus for the greatest part of the
current. We may if desired modify the details or arrangement of our device
without however departing from the nature of our invention.
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. A contact making and breaking device constructed and arranged substantially
as hereinbefore described and shown in the drawings for the purpose specified.
2. In a contact making and breaking device the employment of two coils A and B
having independent windings and appropriate functions the said coils being arranged
and operated as above described.
Dated this 4th dox of Mox 1909
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.