Improvements in Electric Generators and Motors.
Year: 1892

page_text: COMPLETE SPECIFICATION.
Improvements in Electric Generators and Motors.
We WALTER THOMAS GOOLDEN, Electrical Engineer and LLEWELYN
BIRCHALL ATKINSON, Civil Engineer, both of Woodfield Works, Woodfield
Road, Harrow Road, in the County of London, 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 :-
Our invention relates to electric generators and motors particularly to those for
use in mines where they may work in explosive or inflammable atmospheres or
where the working parts of the machine have to be protected from dust, damp, or
mechanical injury from contact with foreign substances.
Our invention has for its object the special construction and arrangement of
covers over the armature, commutator, and brushes broadly according to the
description in Specification of Letters Patent No. 12676 dated 19th September 1887
granted to us but with special regard to means for removing the covers with great
facility for inspection and repairs, for adjusting and regulating the positions of the
brushes upon the commutator from the exterior and for keeping the enclosed
volume of gas or atmosphere within the case as small as possible, by the use of
pockets or recesses for containing the brushes.
In order that our invention invention may be the better understood we will now
proceed to describe the same in relation to the drawings hereunto annexed reference
being had to the letters and figures marked thereon. Like letters refer to like parts
in the various figures...
Figure 1 is a front elevation of a motor or generator with casings, the casing over
the commutator being broken away to show the brushes and brush carrier and
shewing the pockets or expanded portions of the cover containing the brushes.
Figure 2 is a plan of the same with commutator cover in section.
Figure 3 is an end view half in section half in full.
Figure 4 is an end view of the commutator casing showing part in section where
the handle engages through the casing with the brush carrier and showing the
expanded covering or pocket in the cover containing the brushes.
Figures 5 and 6 show modified means for fastening the detachable commutato:
casing together.
Our invention consists in the particular construction and arrangement of casings
and parts in connection therewith whereby the objects hereinbefore described are
carried.
To carry our invention into effect we attach rigidly to the pole pieces A of
the machine, a casing B having a projecting rim C (preferably cylindrical in
form) which covers over the outside of the right hand end of the armature D.
The commutator E is covered over by an oblong cover F which is made in halves
and jointed together by bolts for other suitable devices, being for the most part a
closely or nearly approaching fit to the commutator, but expanding into recesses
or.pockets to contain the brushes.
It has a cylindrical part G which fits tightly over the rim C so as to make a
flame tight joint therewith.
The right hand side of the casing F (Figure 2) is journalled pivotably upon the
bush or bearing brass H.
Windows J are arranged upon detachable doors K at the side of the casing F,
so that the brushes may be viewed through the windows, or if necessary the
detachable door can be removed.
In the cylindrical part G one or more slots g are provided through which screws <
having spring washers c¹ under their heads, penetrate and are screwed into the

page_text: part G; this tends to maintain the casing F in a fixed position against any tendency
to movement from vibration or other such causes.
The brush carrier L is made in halves and jointed by screws 1 and is journalled
upon an extension h of the bearing brass H, so as to turn thereon.
One of the arms of the brush carrier is adapted to extend up close to the interior
surface of the casing F and in this said arm, a handle M is screwed or otherwise
fixed, (which however first passing through the casing F) and thus joints the brush
carrier and casing together, so that in moving one by the handle M, the other is
moved also.
The object of this is, that when the casing is off, the brushes are properly
mounted and the machine will work without the case; and when the casing is on
it is necessary to adjust the position of the brushes, which is done through the casing
itself, by moving casing and brush carrier both together about an axis which is
preferably the axis of the shaft.
As in electrical machines which work for long periods continuously, it is
necessary to have access to the brushes and commutator very frequently,
probably three or four times a day, for the purpose of adjustment, inspection, and
repairs, the casing or parts thereof is made as light as possible and the means of
fastening such as can be operated with little trouble.
In Figures 1 and 2 the commutator casing is held together by only four bolts f
which can be quickly taken out, but in Figures 5 and 6 we show a hinged
fastening.
It will be seen from Figure 6 that on each half of the casing F two lugs N are
arranged, one pair being provided with holes and the other pair having round
spindles n which engage hinge like into the said holes of the first named
lugs N.
On the lower side of the casing F, one lug () is arranged on each half, and a
bolt P having two parts arranged eccentric to one another, engages with holes in
the said lugs O so that on the turning of the bolt P in the said holes, the two
parts of the casing are drawn together and locked in position.
It is obvious that by this arrangement the casing can be removed in a very short
space of time, and can be as quickly replaced.
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 :-
1st. In a dynamo electric generator or motor having a flame tight casing
completely surrounding the armature commutator and brushes, a casing covering
the commutator and brushes adapted to be capable of rotation about an axis and
making sliding gas tight joints with the fixed adjacent parts of the machine,
to permit of the adjustment of the lead of the brushes, the said casing fitting closely
to the contour of the armature and commutator with pockets or expanded recesses
for the brushes.
2nd. A casing covering the commutator and brushes in combination with a brush
carrier adapted to rotate about an axis, and a detachable handle connecting the
brush carrier and casing together, substantially as described.
3rd. In a dynamo electric generator or motor, casings covering the armature,
cominutator and brushes, substantially as described and illustrated in the accom-
nanying drawings.
4th. A casing covering commutator and brushes constructed in parts hinged
together, and with means for fastening same, substantially as described.
Dated this 17th day of June 1892.
FELL & WILDING,
1, Queen Victoria Street, London, E.C., Agents for the Applicants.