Improvements in Regulating Electric Motors.
Year: 1894

page_text: Date of Application, 9th Mar., 1894
Complete Specification Left, 10th Dec., .1894-Accepted, 9th Mar., 1895
PROVISIONAL SPECIFICATION.
Improvements in Regulating Electric Motors.
I JAMES GEORGE WILLCOX ALDRIDGE, of 9 Victoria Street, Westminster,
in the County of London, Civil Engineer, do hereby declare the nature of this
invention to be as follows:-
This invention for improvements in regulating electric motors has for its object
to automatically regulate the current to the motor according to the power to be
exerted by the motor, and consists essentially in causing the transmission of the
power from the motor to the work to be done to compress a spring and in causing
the compression or extension of the spring to actuate an electric switch arrangement
for regulating the current to the motor.
In applying this invention to an electric hoist, the spring actuates a switch
either regulating the sections of the field magnet coils in circuit or inserting or
taking out resistance coils from the circuit.
Dated this 9th day of March 1894.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Regulating Electric Motors.
I JAMES GEORGE WILLCOX ALDRIDGE, of 9 Victoria Street, Westminster,
in the County of London, Civil Engineer, 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 for improvements in regulating electric motors has for its object
to automatically regulate the current to the motor according to the power to be
exerted by the motor, and consists essentially in causing the transmission of the
power from the motor to the work to be done to compress a spring and to actuate
an electric switch arrangement for regulating the current to the motor corresponding
to the compression of the spring.
In applying this invention to an electric hoist, the spring actuates a switch
either regulating the sections of the field magnet coils in circuit or inserting or
taking out resistance coils from the circuit.
In the accompanying sheet of illustrative drawings:-
Fig. 1 is a sectional elevation showing an arrangement for transmitting the
resultant force on the loose pulley at the jib end of a crane to the governing
spring, and
Fig. 2 is a section showing an arrangement by which the fluid actuates the
governing spring and electric controlling switch, and Fig. 3 is a similar view to
Fig. 2 showing a modification.
Fig. 4 is a sectional elevation showing the governor spring adapted to be directly
compressed by the resultant force on the loose pulley at the jib end of a crane
and to actuate the controlling electric switch.
Fig. 5 is a longitudinal section showing the governor spring adapted to be
compressed by the tension of a hauling or lifting chain and mechanically connected
to the controlling electric switch and Fig. 6 is an end elevation of the same.

page_text: Fig. 7 is a vertical section showing the governor spring adapted to be
compressed by the resultant force acting on a guide pulley over which the hauling
or lifting chain passes and mechanically connected to the controlling electric
:switch.
Fig. 8 is a vertical section showing an arrangement for transmitting the resultant
force acting on a guide pulley over which the hauling or lifting chain passes to the
governor spring.
Fig. 9 is a longitudinal section showing the controlling spring adapted to be
compressed in proportion to the torsion of a shaft and communicate its motion to
the controlling electric switch, and Fig. 10 is an end view of the same.
Referring to Fig. 1 the ends of the slat frame a carrying the pulley bare
suitably formed to take into guides c fixed to the crane jib. The inner end of the
frame is fitted with a packing and acts upon a fluid contained in the cylinder d and
passage e so that the resultant force acting upon the pulley forces the fluid along
the passage e.
Referring to Fig. 2 the fluid forced along the passages e, Fig. 1 compresses the
spring and moves the contact piece into a position corresponding with the
resultant pressure on the jib pulley and the comparative strength of the spring f.
The movement of the contact piece g cuts out the resistances ZZZ until the E.M.F.
passed to the motor is sufficient to overcome the resistance of the load.
In Fig. 3, the fluid forced along the passages e Fig. 1 operates a Bourdon tube h
whose free end actuates the contact lever g cutting out the resistances Z.
In Fig. 4 the resultant forces on the jib pulley b compresses the spring f
proportionally to the applied load, giving a consequent corresponding movement
to the rod and the contact lever g of the electric controlling switch.
Referring to Figs. 5 and 6 the pull on the draw hook m compresses the spring f
and operates the contact lever g through the crosshead n and links o.
In Fig. 7 the resultant force of the guide pulley b compresses the spring and
actuates the contact lever g, and in Fig. 8 the resultant force forces fluid from the
cylinder d to a device similar to that shown in Fig. 2 or Fig. 3.
P
In the arrangement shown in Figs. 9 and 10 the pulley is free to turn on the
shaft for endwise motion is prevented by the collars r. The sleeves s can move
axially on the shaft g but cannot rotate on it. The pulley p and sleeves s have
helical projections engaging with one another and as the pulley p is rotated the
sleeves s are forced outwards according to the resistance to rotation of the shaft
against the springs f. The springs are retained in the sleeves by the lock nuts t.
The ring is loose on the left hand sleeves but moves axially with the sleeve.
The axial motion of the ring vis transmitted to the contact lever g of the electric
switch by the links 1, toothed quadrant 2, pinion 3, shaft 4, trundle wheel 5 and
quadrant 6 attached to the lever g. It will be seen that the bars of the trundle
wheel can oscillate to a considerable extent without operating the lever g so that
the contact lever is unaffected by vibration of the load.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare. that what I
claim is :-
1. Regulating electric motors by causing the transmission of the power from the
motor to the work to be done to compress a spring and to actuate an electric
switch arrangement corresponding to the compression substantially as described.
2. The arrangement for regulating electric motors substantially as described
with reference to the drawings.
Dated thie 8th day of December 1801 -
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.