Improvements in Electro Motors.
Year: 1892

page_text: Date of Application, 20th Dec., 1892
Complete Specification Left, 17th Oct., 1893-Accepted, 16th Dec., 1893
Improvements in Electro Motors.
HARRY THEODORE BARNETT M.I.E.E. Electrical Engineer 14 Narcissus
Road London, N.W. do hereby declare the nature of this invention to be as
follows:-
It is for the purpose of providing an electro motor smaller, lighter & more
efficient than is at present obtainable.
It is of that type of apparatus in which the two or more reacting magnets
revolve in opposite directions.
I may state that I am acquainted with the method of double driving obtained
by allowing the field magnet to revolve in a direction opposite to that of the
rotation of the so called armature. This method has many defects chief among
which being that the brushes necessarily rotating to follow the field magnet poles
cannot be adjusted while the machine is in motion.
As an improvement on this device I arrange two so called armatures provided
with suitable commutators spindle axle bearings &c. so that they are situated each
within the others magnetic field, the position at which the current enters & leaves
each of the same being determined by the special requirement involved but is of
course so regulated as to ensure their rotation.
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This rotation being due to a mutual action neither the term "field magnet" nor
armature can be properly applied to either magnetic portion of the apparatus
but the term commutation magnet may conveniently be substituted.
I prefer that all the brushes be situated approximately upon the same plane
& to this end I connect the commutator segments to the sectional winding of
the magnets not immediately opposite to them but to those by a sufficient distance
displaced to secure the desired difference of polar position of the said commutation
magnets.
This motor may be applied to any purpose for which double driving is required
& as its small size & weight & high efficiency may in some cases render its adoption
expedient when single driving only is necessary in such a case I arrange some
suitable device in connection therewith which shall cause the two rotating portions
to engage one with another so that while rotating as they do in opposite directions
yet each may take its share of the load which same may be put entirely upon
either one of the said rotating portions.
I also adopt this device when double driving is used & it is desired that both
commutation magnets should revolve at the same or a proportionally regular
speed.
For this said intergearing I prefer the arrangement obtained by providing each
of the said commutation magnets with a suitable gearing surface between which
& engaging with both is an intermediate wheel free to revolve upon a fixed axle or
bearing.
Dated this 18th day of December 1892.

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HARRY THEODORE BARNETT Mem. Inst. Elec. Engrs. 14 Narcissus Road
W. Hampstead London N.W. 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 is for the purpose of providing an electro motor smaller, lighter,
& more efficient than is at present obtainable.
It is of that type of apparatus in which two or more reacting magnets revolve
in opposite directions.
I may state that I am acquainted with the method of double driving obtained
by allowing the field magnet to revolve in a direction opposite to that of the
rotation of the armature:-The plan has many defects, chief among which being
that the brushes necessarily rotating to follow the field magnet poles cannot be
adjusted while the machine is in motion.
As an improvement on this device I arrange two so called armatures (provided
with suitable commutators, spindles or axles, bearings &c.) so that they are situated
each within the others magnetic field, the position at which the current enters each
of the same being determined by the special requirement involved but of course so
regulated as to ensure their rotation-this rotation being due to a mutual action
neither the term "field magnet" nor "armature" can be properly applied to either
magnetic portion of the apparatus, but the term "commutation magnet
" may
conveniently be substituted.
The motor as above constituted may be applied to any purpose for which double
driving is required but as its small size & weight & high efficiency renders its
adoption expedient where single driving only is necessary in such a case I arrange
some suitable device in connection there with which shall cause the two rotating
portions to engage one with the other, so that, while rotating as they do, in opposite
directions yet each may take its share of the load, which same load may then be
put upon or driven from the pulley or other power transmitting device directly in
connection with one or geared in connection with both of the rotating portions.
I also adopt this intergearing device even where double driving is used if it is
desired that both commutation magnets should revolve at the same or at a
proportionally regular speed. For this said intergearing prefer the arrangement
obtained by providing each of the said commutation magnets with a suitable
gearing surface, between & engaging with both of which is an intermediate wheel
free to revolve upon a fixed axle or bearing.
A convenient form of construction for an electro motor according to this
invention is illustrated by the accompanying drawings & may be described as
follows.
Fig. I is a diagram showing a convenient distribution of magnetic polarity upon
the commutation magnets.
Figs. II & III are sectional & end views of a complete motor.
Two ring armatures of the gramme or Pacinotti type A. A' are provided with
attached commutators F. F the spindles or axles C C¹ projecting at one end only-
the internal diameter of the outer commutation magnet is slightly greater than the
external diameter of the inner one. The armature or commutation magnet of
larger diameter A¹ is attached to its axle &c. by a carrier H. different to that usually
employed in that it does not enter the interior of the armature but is affixed to the
side thereof.
The armatures (or commutation magnets) are mounted by their axles in
bearings D. D¹ carried upon a bed plate. The distance between the bearings is
planned so that when the axles are placed in them (the armatures or commutation

page_text: magnets being between them) the said commutation magnet of smaller diameter is
contained within the one of larger diameter.
The commutators may be (upon the axle) either between the commutation
magnets & bearings or outside the bearings. In the latter case the connecting
wires may pass thro a longitudinal aperture thro' the shaft-which said shaft for
this purpose may be formed of tube.
The pulleys G. G' or other power transmitting devices are situated upon the
axles outside & beyond the commutators & bearings.
The electric current is led to & from the commutation magnets (preferably in
series) by brushes in the usual way. The position of the brushes of course being
regulated to produce that particular contiguity of the polar points necessary for
the production of the desired speed.
The amount of iron in each of the commutation magnets should be approxi-
mately equal & an approximately equal length of the same gauge of current
carrying conductor or wire should be upon each of the opposed faces of the
commutation magnets.
If it is desired that the speed of the two portions of the motor should be equal
or proportionally regular they may be intergeared by means of bevel friction rings
or cog wheels H H fixed to each of the axles or commutation magnets, both of
the said bevel friction rings or cog wheels engaging with I a fixed centre bevel
friction or cog wheel common to both.
It is obvious that in this arrangement the power may be transmitted from either
commutation magnet axle or from the intermediate gear wheel I as may be most
convenient.
If the motor is belt driving thro' or to a shaft the intergearing would not be
required as one of the belts could be crossed.
It should be understood that there are many ways of making motors in
accordance with this invention-the method of construction particularly specified
above has been used by me & found satisfactory.
Having now particularly ascertained & described what is the nature of my said
invention what I claim is as follows:-
Claim I. An electro motor consisting of two commutation magnets & their
appurtenances substantially as described.
Claims II. In an electro motor consisting of two commutation magnets & their
appurtenances the combination therewith of an intergearing device consisting of
a gear wheel attached to each commutation magnet and a third gear wheel
free to revolve upon a fixed bearing or axle substantially as & for the purpose
described.
Dated this 18th day of September 1893.
HARRY THEODORE BARNETT.