IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES
Year: 1886

page_text: Date of Application, 11th Mar., 1886.
Complete Left, 11th Dec., 1886.
Complete Accepted, 1st Feb., 1887.
I ROOKES EVELYN BELL CROMPTON of Mansion House Buildings Queen Victoria
Street in the City of London Engineer, do hereby declare the nature of my invention
for IMPROVEMENTS IN DYNAMO-ELECTRIC MACHINES to be as follows:-
My improvements relate to dynamo-electric machines more particularly when used
for the transformation of a current of electricity into motive power and relates more
especially to the convenient handling and manipulation of such electro dynamic motors
which I hereafter will call "motors." For convenience I also call the current
supplied to the motor by the Generator "nain current."
In the case of such motors as are required for hoisting purposes, working lifts and
training cannon where gradual starting and stopping is required and where the power
required is intermittent I so design and proportion the winding of the various parts of
the motor which I require to work with a supplied current of electro motive force
(which 1 hereafter abbreviate "E. M. F.") that the turning moment (which I here-
after call "torque ") is very great even when the main current is comparatively small.
In other words I wind both the armature and field magnets of the motor with a greater
number of turns of fine wire than has hitherto been used in dynamo machines used
as motors with a main current of the same E. M. F.
To determine how far I may go in the direction of obtaining a great torque by a
large number of convolutions of wire it is necessary for me to consider what is the
longest period the motor is likely to be required to work slowly or to stand fast
exerting this required maximum of torque.
At these times as the motor is generating little or no counter E. M. F. the current
passing through the motor will vary as its fixed resistance (consisting of that of the
armature and of the field magnets in series with it, or if the motor be compound
wound of the combined total resistance of the whole machine.)
In such cases where the maximum of torque is only required for a very few moments
for starting or stopping purposes I so proportion my resistance that the current passing
under the above mentioned circumstances may not exceed that amount which would
heat up the whole of the insulating coils on the machine to a dangerous degree in the
time during which this large amount of current will be passing.

page_text: To give an example-if it be found necessary to have the motor standing with
current on thus holding up the weight, or very slowly revolving for a period of one
minute I make the resistance such that the maximum of current which can pass would
not heat up the insulating coils to a dangerous degree in one minute.
Therefore for long lifts at a rapid rate with very short periods of slow movement for
starting and stopping at the end of each lift I can use finer wire and hence obtain a
greater number of convolutions and greater torque for a given size of machine than I
can do when my periods of slow movement at starting and stopping occur at more
frequent intervals and occupy a longer time.
The so proportioning of the number of convolutions and hence the safe size of wire
to the required periods of heavy current and subsequent periods wherein the wire can
cool down, enables me to arrange the controlling gear of the motors used in the above
mentioned manner in excessively simple fashion. That is to say I can start at slow
speed, increase to full speed, slow again gradually down till I stop, start again at slow
speed in the opposite direction increase the speed up to full speed in the opposite
direction and so on, with the one simple angular movement of the collecting brushes
round the commutator or collecting cylinder of any continuous current dynamo
machine or motor.
It will be seen that what is necessary to effect this in a convenient manner, is to
make the electrical connections from the brushes to the terminals or to the field
magnets by means of flexible connections of great length or what is still more
convenient to supply two rubbing connections consisting of two complete circles
insulated one from the other to one of which is attached the terminal which would be
naturally connected to one brush whilst the other terminal, or one end of the field
magnet circuit as the case may be, is attached to the other circle.
The brushes themselves are mounted in a frame so as to revolve concentrically with
the armature spindle and hence with the cylindrical surface of the commutator. Each
respective brush holder may be provided with a contact brush for the purpose of
making continuous contact with the two circles just mentioned.
One end of the frame carrying the brushes may be prolonged into the form of a
convenient lever and worked by the hand direct so as to obtain the above mentioned
desired range of motions of the motor.
Again when it is desired to move the brush frame from a distance this can be done
by a worm wheel and gearing or by a chain wheel and pitched chain or by any other
well known mechanical device.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London,
Agents for the said R. E. B. Crompton.

page_text: проспецию ш Dупато-1бито маслицев.
I ROOKES EVELYN BELL CROMPTON of Mansion House Buildings Queen Victoria
Street in the City of London 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 :-
My improvements relate to dynamo electric machines more particularly when used
for the transformation of a current of electricity into motive power and relates more
especially to the convenient handling and manipulation of such electro dynamic motors
which I hereafter will call "motors." For convenience I also call the current supplied
to the motor by the Generator "main current."
In the case of such motors as are required for hoisting purposes, working lifts and
training cannon where gradual starting and stopping is required and where the power
required is intermittent I so design and proportion the winding of the various parts of
the motor which I require to work with a supplied current of electro motive force
(which I hereafter abbreviate "E M F") that the turning moment (which I hereafter
call "torque") is very great even when the main current is comparatively small. In other
words I wind both the armature and field magnets of the motor with a greater number
of turns of fine wire than has hitherto been used in dynamo machines used as motors
with a main current of the same E M F.
To determine how far I may go in the direction of obtaining a great torque by a
large number of convolutions of wire it is necessary for me to consider what is the
longest period the motor is likely to be required to work slowly or to stand fast
exerting this required maximum of torque.
At these times as the motor is generating little or no counter E. M. F. the current
passing through the motor will vary as its fixed resistance (consisting of that of the
armature and of the field magnets in series with it, or if the motor be compound wound
of the combined total resistance of the whole machine).
In such cases where the maximum of torque is only required for a very few
moments for starting or stopping purposes I so proportion my resistance that the
current passing under the above mentioned circumstances may not exceed that amount
which would heat up the whole of the insulating coils on the machine to a dangerous
degree in the time during which this large amount of current will be passing.
To give an example-if it be found necessary to have the motor standing with
current on thus holding up the weight, or very slowly revolving for a period of one
minute I make the resistance such that the maximum of current which can pass would
not heat up the insulating coils to a dangerous degree in one minute.
Therefore for long lifts at a rapid rate with very short periods of slow movement
for starting and stopping at the end of each lift I can use finer wire and hence. obtain
a greater number of convolutions and greater torque for a given size of machine than
I can do when my periods of slow movement at starting and stopping occur at more
frequent intervals and occupy a longer time.
The so proportioning of the number of convolutions and hence the safe size of wire
to the required periods of heavy current and subsequent periods wherein the wire can
cool down, enables me to arrange the controlling gear of the motors used in the above
mentioned manner in excessively simple fashion. That is to say I can start at slow
speed, increase to full speed, slow again gradually down till I stop, start again at slow

page_text: speed in the opposite direction increase the speed up to full speed in the opposite
direction and so on, with the one simple angular movement of the collecting brushes
round the communicator or collecting cylinder of any continuous current dynamo
machine or motor.
It will be seen that what is necessary to effect this in a convenient manner, is to
make the electrical connections from the brushes to the terminals or to the field
magnets by means of flexible connections of great length or what is still more con-
venient to supply two rubbing connections consisting of two complete circles insulated
one from the other to one of which is attached the terminal which would be naturally
connected to one brush whilst the other terminal, or one end of the field magnet
circuit as the case may be, is attached to the other circle.
The brushes themselves are mounted in a frame so as to revolve concentrically with
the armature spindle and hence with the cylindrical surface of the commutator. Each
respective brush holder may be provided with a contact brush for the purpose of
making continuous contact with the two circles just mentioned.
One end of the frame carrying the brushes may be prolonged into the form of a
convenient lever and worked by the hand direct so as to obtain the above mentioned
desired range of motions of the motor.
Again when it is desired to move the brush frame from a distance this can be done
by a worm wheel and gearing or by a chain wheel and pitched chain or by any other
well known mechanical device.
I will now proceed to describe the manner of carrying my invention into practical
effect that is to say I construct my improved dynamo electric machine with a high
resistance armature, and a field so wound that when the four limbs are coupled in
parallel and put in series with the armature a high resistance motor is obtained.
The brushes are attached to a rocking bar or support which turns round the axis of
the armature, its position being controlled by a suitable lever or by other hand gear.
On the same support as the brushes is a commutating drum, the ends of the coils of
the field magnets being led to rubbing pieces. This commutator drum is the same in
principle as the well known Planté rheostat, and serves to connect the four coils either
all in series, two series two parallel, or all in parallel. It is so arranged that when the
brushes are in, position for full speed in either direction the coils areall parallel ;
at position for stopping they are all in series, being two series two parallel in the
mediate position. Thus when the motor has a large counter electromotive force it
has a low resistance, and when the counter electromotive force is low or nil the motor
has a high enough resistance to prevent its being injured.
but
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim is —
1. In a dynamo electric machine used as a motor the combination or arrangement
and use of a high resistance armature, high resistance field magnets of the character
described, moveable brush holder and field coupling arrangements together with the
ordinary accessory parts whereby the machine is enabled to bear the whole E. M. F.
of circuit even when at rest and is capable of regulation as to torque, speed and
direction of rotation in manner and for the purposes hereinbefore set forth.
2. In a dynamo electric machine used as a motor the combination or arrangement
and use of parts for facilitating the regulation of the machine by effecting the
coupling of the field magnet coils of the machine and the movements of the brushes
by one and the same movement given to a handle or equivalent operating part as
set forth
WM. BROOKES & SON,
55 & 56, Chancery Lane, London,
Agents for the Applicant.