Improvements in Regulators for Dynamo-electric Machines.
Year: 1892

page_text: Date of Application, 7th Oct., 1892
Complete Specification Left, 5th Aug., 1893-Accepted, 9th Sept., 1893
PROVISIONAL SPECIFICATION.
Improvements in Regulators for Dynamo-electric Machines.
We, THOMAS REGINALD ANDREWS and THOMAS PREECE, of the Firm of
Andrews and Preece, Limited, Borough Mills, Bradford, in the County of York,
Electrical Engineers, do hereby declare the nature of this invention to be as
follows:-
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This invention relates to improvements in regulators for dynamo-electric machines
and its object is to provide a simple arrangement adapted in the case of a "series
wound" dynamo to maintain a constant current with a varying electromotive force,
and in the case of a "shunt" or a compound" wound dynamo to maintain a
constant electromotive force at the terminals of the dynamo with a varying current.
For this purpose we employ the core of a solenoid to operate a plunger within a
cup or vessel containing mercury for the purpose of varying the height of the
mercury therein and in the manner herein described increase or decrease the
resistance of the circuit in which the apparatus is placed. The resistance is created
in the circuit by a resistance box, rheostat or its equivalent placed in series with
the circuit and the wire coils of the resistance box are each connected to a thin
metal plate. These plates are placed one above the other but are each insulated
and they have a concentric hole forming the above mentioned cup or vessel of
mercury or the upper part of the walls of said vessel are formed by said plates.
By this arrangement when the said plunger is operated by the solenoid the mercury
metallically connects a greater or less number of said plates and so decreases or
increases the resistance.
In the case of a "series" wound dynamo the solenoid is wound with similar wire
to that of the field magnets and is in series there with and the core of the solenoid
is so balanced, counterweighted or arranged that when the current varies from the
normal it is raised or lowered thereby operating the plunger and altering the
resistance. The resistance may be placed as a "shunt" circuit across the brushes
of the dynamo thereby increasing or decreasing the current round the coils of the
field magnet.
"
To maintain a constant electromotive force with a varying current in a
"compound or
"shunt" wound dynamo the solenoid of the regulator is formed of
"shunt"
fine wire having sufficient resistance to allow it to be coupled up as a
circuit connecting the terminals of the dynamo. And the resistance box or its
circuit of the dynamo
equivalent is arranged in series with the ordinary "shunt"
or it may be placed in a second "shunt" circuit off the "shunt" circuit of the
dynamo. The core of the solenoid is so arranged that when the electromotive force
varies from the normal the resistance is decreased or increased and a greater or
less current passes through the coils of the field-magnets of the dynamo.
Dated this 6th day of October 1892.
· DRACUP & NOWELL,
Bradford, Agents..
COMPLETE SPECIFICATION.
Improvements in Regulators for Dynamo-electric Machines.
We, THOMAS REGINALD ANDREWS and THOMAS PREECE, of the Firm of
Andrews and Preece, Limited, Borough Mills, Bradford, in the County of York,
Electrical Engineers, 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 :-
This invention relates to improvements in regulators for dynamo electric machines

page_text: and its object is to provide a simple arrangement adapted in the case of a " series
wound" dynamo to maintain a constant current with a varying electromotive force,
and in the case of a "shunt"
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or a compound" wound dynamo to maintain a
constant electromotive force at the terminals of the dynamo with a varying current.
For this purpose we employ the core of a solenoid to operate a plunger within a
cup or vessel containing mercury for the purpose of varying the height of the
mercury therein and in the manner herein described increase or decrease the
resistance of the circuit in which the apparatus is placed.
The resistance is created in the circuit by a resistance block rheostat or its
equivalent placed in series with the circuit and the wire coils of the resistance 'box
are each connected to a thin metal plate. These plates are placed one above the
other but are each insulated and they have a concentric hole forming the above
mentioned cup or vessel of mercury or the upper part of the walls of said vessel are
formned by said plates. By this arrangement when the said plunger is operated by
the solenoid the mercury metallically connects a greater or less number of said
plates and so decreases or increases the resistance.
In the case of a " series
wound dynamo the solenoid is wound with similar wire
to that of the field magnets and is in series therewith and the core of the solenoid
is so balanced, counterweighted or arranged that when the current varies from the
normal it is raised or lowered thereby operating the plunger and altering the
resistance. The resistance may be placed as a "shunt" circuit across the brushes
of the dynamo thereby increasing or decreasing the current round the coils of the
field magnet.
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دو
To maintain a constant electromotive force with a varying current in a
compound" or shunt" wound dynamo the solenoid of the regulator is formed of
fine wire having sufficient resistance to allow it to be coupled up as a
"shunt
circuit connecting the terminals of the dynamo. And the resistance box or its
equivalent is arranged in series with the ordinary "shunt" circuit of the dynamo.
The core of the solenoid is so arranged that when the electromotive force varies
from the normal the resistance is decreased or increased and a greater or less
current passes through the coils of the field-magnets of the dynamo.
Reference is to be had to the accompanying sheet of drawings forming a part of
this Specification in which similar letters of reference indicate corresponding parts
in each of the figures.
Figure 1. represents a plan view of the regulator.
Figure 2, is an elevation of the same. .
Figure 3, is a vertical section.
The resistance coils numbered 1 to 24 are mounted between the discs A and A¹
of non-conducting material connected together by the central pillar B. The coils 1
to 24 are connected in series and preferably increase in conductivity from the first
to the last that is to say the wire forming the coil marked 24 is a considerably
better conductor or is of a larger guage than the wire forming the coil marked 1 and
there may be a little difference in this respect between each coil.
Besides being connected in series the resistance coils are each connected to one
of the 24 thin metallic plates C, by the connecting wires D, and the plates Care
thoroughly insulated from each other by a piece of non-conducting material E
introduced between each of the plates. The plates C and non-conduction material E
are clamped between the end plates F and F by the bolts G and are mounted on
the top of the pillar B over the disc A and the cylindrical hole H. The hole H is
formed in the pillar B and is filled with mercury and a concentric hole J is formed
through the whole of the plates to admit the plunger K of non-conducting material
to the mercury. The plunger K is connected to the core L of the solenoid M' and
the latter is mounted upon the annular block or spacing piece N fixed on the top
of F¹
When the electric current is passed through the solenoid the core L is more or
less raised according to the strength of the current thereby raising the plunger L
to a similar extent and this displacement of the plunger correspondingly lowers the

page_text: height of the mercury in J. As the mercury falls the metallic connection between
the plates C is severed one at a time thereby introducing the resistance of one coil
at a time until assuming the plunger is sufficiently raised to lower the mercury
clear of the plates the full resistance of the whole of the 24 coils is introduced. An
annular balance weight P surrounding the casing R is connected to the top of the
core L by the cords S, S, passing over the pulleys T mounted in the cap U and
this weight is provided to assist the magnetic force of the solenoid to raise the core.
But this weight is not sufficient to prevent the core returning to the normal position
shown in the drawings when the current is switched off the solenoid and its magnetic
force is not in action.
The solenoid is constructed and arranged and the apparatus is placed in circuit
with the dynamo by means of the couplings O, O (respectively connected to the
top and bottom plates of the series of plates C) as above described according to the
type of dynamo to which it is applied.
It will be readily understood that as the magnetic force of the solenoid varies
with the current passing through it, and also as its power to move the core depends
upon the position of the latter, more or less resistance is introduced into the circuit
in which the apparatus is placed as the current in such circuit fluctuates and in this
manner a constant current or electromotive force is maintained according to the
type of dynamo to which the regulator is applied.
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:
A dynamo regulator consisting of a rheostat the resistance of which is adapted
to be increased or decreased by the core of a solenoid fitted with a plunger arranged
to regulate the level of a cup of mercury and thereby reduce or increase the
resistance of the circuit in which the rheostat is placed, substantially as herein
shown and described.
Dated this 4th day of August. 1893
DRACUP & NOWELL,
Bradford, Agents.