Automatic Load Starting Apparatus applicable to Synchronous Alternating Current Motors.
Year: 1899

page_text: Date of Application, 11th Dec., 1899
Complete Specification Left, 6th Sept., 1900-Accepted, 27th Oct., 1900
PROVISIONAL SPECIFICATION.
Automatic Load Starting Apparatus applicable to Synchronous
Alternating Current Motors.
WE, CONRAD LUDVIG ROSENQVIST, ARTHUR BERGTHEIL, and HENRY WILSON
YOUNG, all of 12, Camomile Street, Bishopsgate Street Within, London, E.C.,
Electrical Engineers, do hereby declare the nature of this invention to be as
follows;-
This invention relates to automatic load starting apparatus applicable to
synchronous alternating current motors, and is designed by an electromagnetic
belt or clutch device coming only into full operation when the motor is running
synchronously to enable the motor to first start light until it is running in
synchronism and thereafter to throw on the load gradually and automatically.
It is known that in starting a synchronous alternating current motor under
full load, a greater amount of energy is required in so starting, than when the
motor does the same amount of work running in synchronism; it is also difficult
to make the motor armature attain synchronism when the load is great at
starting.
To remedy this, we connect the motor not direct to the shafting carrying the
load but through a counter shafting, by a belt and fast and loose pulley or through
any equivalent engaging or disengaging clutch
The engagement of the belt or clutch with the shafting carrying the main
load is effected by a shifting device, arranged so that when the motor is starting
it is free from the main shafting but as soon as synchronous speed has been
attained, the shifting device automatically moves over the belt or other clutch
to engage with the shafting carrying the main load.
The shifting device will maintain this connection with the main load, so long
as the motor is running in synchronism, and no longer; and when the motor
is stopped the disengagement of the motor to the main load shafting is effected
so as to be ready for re-starting light.
The automatic shifting device depends for its operation upon a solenoid or
coil of wire energized by a direct current, obtained from that part of the armature
circuit which is connected to the commutator, and such direct current is obtained
only when the motor is working synchronously.
When this solenoid is energized by a direct current it suffices to attract a
core against a weight or spring re-action and to move over the shifting device
to throw in the connection of the motor with the main load shafting.
When the motor is out of synchronism and only a alternate current is passing
in this solenoid the inductive force generated in the coil is so nearly equal to
that supplied, that no sufficient magnetisation is effected to operate the shifting
device.
When the direct current ceases or when the motor is stopped, the reaction
of a weight or a spring will cause the reverse movement of the shifting device
to normal breaking connection between the motor and the main load shafting,

page_text: and the motor is thus in a position to recover synchronism or to make a fresh
start light.
Dated this 11th day of December 1899.
FELL & JAMES,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.
Automatic Load Starting Apparatus applicable to Synchronous
Alternating Current Motors.
WE, CONRAD LUDVIG ROSENQVIST, ARTHUR BERGTHEIL, and HENRY WILSON
YOUNG, all of 12, Camomile Street, Bishopsgate Street Within, London, E.C.,
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 automatic load starting apparatus applicable to
synchronous alternating current motors, and is designed by an electromagnetic
belt or clutch device coming only into full operation when the motor is running
synchronously to enable the motor to first start light until it is running in
synchronism and thereafter to throw on the load gradually and automatically.
It is known that in starting a synchronous alternating current motor under
full load, a greater amount of energy is required in so starting, than when the
motor does the same amount of work running in synchronism; it is also difficult
to make the motor armature attain synchronism when the load is great at
starting:
To remedy this, we connect the motor, not direct to the shafting carrying the
load but through a counter shafting, by a belt and fast and loose pulley or through
any equivalent engaging or disengaging clutch.
The engagement of the belt or clutch with the shafting carrying the main
load is effected by shifting device, arranged so that when the motor is starting
it is free from the main shafting, but as soon as synchronous speed has been
attained, the shifting device automatically moves over the belt or other clutch
to engage with the shafting carrying the main load.
The shifting device will maintain this connection with the main load, so long
as the motor is running in synchronism, and no longer; and when the motor
is stopped the disengagement of the motor. to the main load shafting is effected
so as to be ready for re-starting light.
This automatic shifting device depends for its operation upon a solenoid or
coil of wire energized by a direct current. obtained from that part of the armature
circuit which is connected to the commutator, and such direct current is obtained
only when the motor is working synchronously.
When this solenoid is energized by a direct current it suffices to attract a
core against a weight or spring re-action, and to move over the shifting device
to throw in the connection of the motor with the main load shafting.
When the motor is out of synchronism and only an alternate current is passing
in this solenoid the inductive force generated in the coil is so nearly equal to
that supplied, that no sufficient magnetisation is effected to operate the shifting
device.
When the direct current ceases or when the motor is stopped, the reaction

page_text: of a weight or a spring will cause the reverse movement of the shifting device
to normal, breaking connection between the motor and the main load shafting,
and the motor is thus in a position to recover synchronism, or to make a fresh
start light.
And in order that our invention may be the better understood we now proceed
to describe the same with reference to the drawings hereto annexed and to the
letters and figures marked thereon.
Figure 1 is an elevation of our apparatus.
And Figure 2 is a plan of the same the over-head shafting being removed.
A is an electro-motor adapted to be operated by an alternating current and
self-exciting. The motor drives the main shafting or work through a counter
shaft B, (having upon it a fast and loose pulley C and D) by a band E, or by
any equivalent engaging or disengaging clutch.
F is a shifting device. applicable as shown, as a fork. for moving the band E
from the loose to the fast pulley of the counter shaft, or vice-versa, but it is obvious
that the movement of this shifting device may be utilised to move a clutch or
similar engaging or disengaging apparatus into or out of gear.
The shifting device F is operated by a bell cranked arm G provided with a core,
adapted to enter a solenoid coil H when the latter is energized, or to drop there-
from by its own weight, or an equivalent recoil spring, when the solenoid coil
ceases to be sufficiently energized to attract the core.
The solenoid coil is connected by the circuits K, L, to that part of the armature
circuit of the motor, which is connected to the commutator, and a direct current
is only obtained in such circuit when the motor is working synchronously.
Under these latter circumstances, the core G is attracted into the solenoid
coil H and the shifting device F moves the strap E on to the fast pulley of the
counter shaft, and throws the work on to the motor.
Should the motor fall out of synchronism, the strap is automatically shifted
to the loose pulley, and remains there, for re-starting or until the motor runs
in synchronism.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what we
claim is:
1st. In combination with an alternating current electro-motor; a solenoid
coil energized by a direct current obtained from that part of the armature circuit
which is connected to the commutator; and a core adapted to enter. against a
recoil weight or spring into the said solenoid coil, when energized by a direct
current, operating a device for shifting a strap, or for connecting and discon-
necting the motor from its main load, substantially as and for the purposes
set forth.
2nd. In combination; an alternating current electro-motor; means for electri-
cally attracting a core or armature, energized only when supplied with a direct
current from the said motor when running synchronously and means for the
connection or disconnection of the said motor to or from its work, operated by
the movement or recoil of the said core or armature.
3rd. The combination with an alternating current electro-motor of means for
automatically connecting and disconnecting the said motor from its work when
running synchronously or otherwise respectively, substantially as described and
illustrated herewith.
21
1
J
1
1
1000
FELL & JAMES,
1, Queen Victoria Street, London, E.C.,
Agents for the Applicants.