July 26, 1932.
1,869,187
H. DREGHQRN
COMMUTATOR TYPE DYNAMO ELECTRIC MACHINE
Filed Feb; 26, 1950
él‘lIV/HIIH
59
A?
‘ Inventoh‘ 1
Herbert Dr-eghorn,
‘b9
His-'Attomeg. v
Patented July 26, 1932
1,869,187
‘_ UNITED starts PATENT curios ‘
1 HERBEBT~DREGHORN, OF RUGBY, ENGLAND, ASSIGNOR '1‘0 GENERAL
ELE'cTnrc' com:
PANY, A ‘CORPORATION OF NEW‘YORK 7
COMMUTATOR TYPE‘DYNAMO ELECTRIC MACHINE.
" Application ?led February 26, 1930,» Serial No. 431,598,‘and in Great Britain March 5,‘ 1929.
The object of‘ my invention isto improve commutation sparking but it also has the
disadvantage that‘it requires expensive and
chines employing commutated windings and complicated'meansto vary its excitation and
the commutation of dynamo electric ma
the principal object of my invention is to thus vary its speed. The brush shifting mo
tor has the advantage that its speed is varied
by simply shiftingits brushes but‘it has the ~
rent commutator motors.
‘
It is well known to those skilled in the art disadvantage that stationary interpoles can
that the usual multiplexor simplex direct not be used to reduce commutation sparking.
current armature winding consists of a plu Compared with an equal make and physical
10 rality of closed coils and there are several size of non-brush shifting motor employing 6.0
- 5 improve the commutation of alternating cur
coils in series between any two consecutive interpoles, the brush shifting motor employ- : .1'
commutator brushes having opposite polarity ing the usual armature winding must‘ reduce
and the voltages of these several coils aid the magnetic ‘flux density per pole so as ‘to
each other in making up the voltage existing reduce the commutation sparking to an ac
16 between those two brushes. The voltage be ceptable degree, thus reducing the‘ horse
tween any two adjacent commutator seg power output per pole and resulting in an .
ments will be the voltage of one of its coils uneconomical motor construction. It is
and with the full pitch or usual fractional therefore desirable to combine the advan
pitch windings this coil will consistof con tages of both‘ types of motor‘so as tosecure
90 ductors lying in two armature core slots un
a motor whose speed is varied by shifting
der the in?uence of opposite magnetic polari: its brushes and which may be operated with t
ties and hence the ‘voltages in these conduc the same or nearly the same magnetic flux ‘
tors aid each other in making up the voltage density per pole as the non-brush shifting
between two adjacent commutator ‘segments. motor employing interpoles and hence with
’ 25 The usual direct current machine has a sta
the same or nearly‘the same horse power out 75
tionary magnetic ?eld and stationary com put per pole. This combination is highly
mutator brushes, thus permitting the placing desirable in high speed, high horse power out
of the brushes so that the slot conductors of put alternating current commutator motors
‘the coils short circuited by the brushes will since these motors necessarily have few poles
'3O‘Qb'e in‘the weakest magnetic field possible, and due to their high horse power output
80
namely, about half way between the main must have a high magnetic flux density per 1.;
‘poles, thereby reducing the ‘voltage between pole and especially desirable is this combi
the adjacent commutator segments short cir nation where these motors require only a
cuited by the‘brushes and reducing commuta narrow speed regulation, thus not warrant
35 tion sparking, and in addition this also per~ ing the use of the non-brush shifting motor 35
‘mits the use of interpoles to further reduce with its expensive and complicated speed
changing means. Examples of high speed,
commutation sparking.
Alternating current commutator motors
are of two general classes, the brush shifting
.' to type and the non-brush shifting type. The
alternating current ‘commutator motor has
a rotating magnetic ?eld and if'the usual
armature winding is employed the voltage
‘high horse power output motors with nar
row speed regulation are those motors which
drive centrifugal boiler feed pumps whose 90
speed is varied only in proportion to ?uctua- .
tions in the boilersteam pressure.‘
To provide the desired combination, it has
between the two adjacent commutator seg-' hitherto been proposed to employ an arma
' '45 ments short circuited by a brush will be the ’ ture winding in which the voltages of the coils 9
full voltage of one of the coils, thus tending in series between two consecutive brushes. a.‘
to I produce commutation‘ sparking‘. -' The having opposite polarity will aid each other
non~brush shifting motor has the advantage in making up the voltage between the two
that its brushes are stationary, thus permit brushes, whereas the voltage between the two
" ‘ 5° tint1r
use of inter
,
b the
,
v
P oles to
g
reatlv
reduce
.
adjacent commutator segments short circuit
100
1,869,187
ediby a brush is the difference between the maining ends of the coils connected together.
nearly equal voltages of two coils in series, Each coil has-at least two active conductors,
thus giving very low voltages between the two and the corresponding conductors of the coils
adjacent commutator segments. This results having different winding pitches are so ar 70
’ in greatly reduced commutation sparking ranged on the core that the voltage between
which permits the operation of the brush adjacent commutator segments is the differ
shifting motor with high magnetic flux ence between the voltages of two active con
,
density per pole and consequently with high ductors.
My invention will be best understood from
horse power output perpole. The need for
my invention and the advantages thereof will the following description when considered in
be better understood after reading the follow connection with the accompanying drawing
10
75
ing brief description of vthestructure and op~' while the features of my invention which are
believed to be novel and atentable are point
eration of vthe two forms of commutated ar
ed out in the appended c aims'
mature winding hitherto proposed. First, a
'
The single ?gure of the drawing represents
plurality of spaced apart conductors are
80
laced on the armature core with the front a development of a portion of a drum type
end of each conductor connected tothe com simplex armature winding arranged in ac
mutator,-and the back ends of the conductors cordance with my invention. In the single
connected together. Second, a ring winding figure shown, 10 represents an armature core,
consisting of spaced apart coils, each coil hav.~ 11 represents the armature core slots ‘12 and
13 represent two brushes resting on t 'e com
mutator 14}, which consists in part of spaced
20
ing at least two active conductors, with one
end of each coil connected to the commutator
and the other ends of the coils connected to
gether; or a drum winding consisting of coils
segments 15 to 24, inclusive. Some of the ar
mature coils are represented by 40 to 51 inclu~
having equal winding pltches w1th each COll sive and to assist in the explanation of my in
having at least one turn and with one end of vention I have represented the coil 40 as hav
each coil connected to the commutator and ing the slot conductors 52 and 53, the coil 41 as
25
the other ends of the coils connected together. having the slot conductors 541 and 55, the
As between the two winding forms, all fac coil 49 as having the slot conductors 56' and
tors being equal, the first has the advantage 57, the back. end connections are represented
of giving the smaller voltage between ad] a by 58 and the front end connections are rep
cent commutator segments, because this volt resented by 59. A conductor 39 connects to
age is the difference between the voltages gen— qgether a corresponding end of each coil, While
erated in two adjacent conductors, but it has the remaining corresponding ends of the coils
the disadvantage of not being adapted for are connected to the commutator 14 by the
'30
35
90
95
100
use on commercial voltages because each coil. _' front end connections 59. As the motor has
has only one active conductor. The second a rotating magnetic ?eld, therefore N and‘ S
form has the advantage of being adapted for represent some of thefexciting poles of‘ the
use on commercial voltages because each coil motor in a certain relationship to the arma
has at least two active conductors, but it has
40
7 ture coils at a certain instant.
The drawing shows any armature having
the disadvantage of giving a higher voltage
between adjacent commutator segments be coils of two diiferent winding pitches with
cause the ‘voltage generated in each active each pair of coils of different winding'pit'ches
conductor of a coil connected to one segment
45
having corresponding slot conductors lying
I10
is lower than the voltage generated in the cor in a common core slot andv the other corre-‘
responding conductor of a coil connected to sponding slot conductors lying in adjacent
slots. For E‘JXELIIIPlEACOllS 40 and- 41 have
theadjacent segment. It was, therefore, de core
different
winding pitches with their corre
- sirable to provide a commutated armature
50
55
winding which has the advantages of both
of the winding forms referred to without hav
ing their disadvantages, because such a wind
ing will operate on commercial voltages with
reduced commutation sparking for a given‘
horse-power output, thus improving the mo—
tor operation, or for a given degree of com
sponding slot conductors 52 and 5,45 lying in
a common core slot andv their other corre-'
sponding slot conductors 53.and 55 lying in
adjacent core slots. Equal‘ voltages will‘ be
generated in slot conductors 52 and 54‘ be
cause they lie in the same core slot, and the
same Willbe true of slot conductors 53‘ and 56. 120
mutation sparking the armaturev winding Also, equal voltages will be generated in slot
will‘ operate with a higher magnetic ?ux conductors 52, 54 and 57 because they are cut
‘ density, and: consequently a higher. horse ting equal values of magnetic ?ux, and the
power output per pole, thus decreasing the same will be true of slot conductors 53, 55'andvv 125
cost of the motor for a given horse-power. 56. But at the instant represented, the volt
This desired commutated armature winding’ age generated in slot conductors‘ 52,54 and
1s provided for by my inventlon, which con- 57 will be slightly higher than the voltage
sists of an armature winding having. coils of generated in slot conductors 53, 55 and 56,
unequal'winding pitcheswith one endof'each because thevalue of'the magnetic ?ux cut by,’ - 130
the former is slightly higher than that cut by
65 0011 connected to the commutator and the re
1,869,187
3
the latter. The directions of the voltages tion with a simplex drum type armature‘
generated in these slot conductors at the ‘as winding having one turn per coil with each
sumed instant may be represented by the ar coil consisting of two slot conductors but it
rowheads shown on them. The voltages gen will be evident that my‘ invention is applic
erated in the two slotconductors of each coil able to any form of commutated winding
aid each other. The voltage between brushes irrespective of the number‘ of turns per coil
12 and 13 is the sum of the voltages generated or slot conductors per turn. Accordingly I
in coils 40 and 49. p This may be seen by desire to have it understood that the embodi
10
starting from brush 12 and tracing through ‘ments shown are only illustrative of my in-_
front end connection 59, slot conductor 52, vention and that such other modl?catlons of
backend connections 58, slot conductor 53, my invention as come within its true spirit
conductor 39, slot'conductor 57, back end con and scope are intended to be included withi
'
nections 58, slot conductor 56, and front end the scope of the appended claims.
' connection 59, to brush 13.
It is seen that the
What I claim as new and desire to secure
80
voltages in slot’ conductors 52, 53, 57 and 56 by Letters Patent of the United States, is:
1. In a dynamo electric machine, the com
aid each other. If the coils were of equal
pitches and were placed on the core in accord bination with an armature core and a com
ance with the prior art, then every two corre mutator having all of its segments insulated
sponding slot conductors of a pair of coils from each other, of an armature winding
20
would lie in adjacent slots; hence, slot con comprising a plurality of separate coils hav
ductors 52 and 54 would lie in adjacent slots, ing a plurality of different pitches, said
85
and slot conductors 53 and 56 would lie in, winding being mounted on said core so that
adjacent slots. The voltage generated be the axes of coils with different pitches fol
tween brushes 12 and 13 would be only low each other in consecutive order around
slightly higher than that with the coils ar said core, means for connecting together a ‘
ranged in accordance with my invention as corresponding end of each of said coils, and
shown‘ in the drawing, and, therefore, my means for connecting the remaining ends of
armature winding is suitable for operation on said coils to consecutive commutator seg
the same voltage as the armature windings ments in the order in which the axes of the
30 of the prior art.
1
coils are located around said core.
’
95
2. In a dynamo electric machine, the com
But the important di?erence between the
prior art armature windings and my arma bination with an armature core having a plu
ture winding is in their respective voltages rality of slots and a commutator having all
between adjacent commutator segments. In of its segments insulated from each other, of
35
the prior art armature winding there is a an armature winding comprising a plurality ~
voltage diiference between every two corre of separate coils each containing at least two
sponding slot conductors of the coils having slot conductors, the slot conductors of said?
an end connected to adjacent commutator coils being disposed in said slots, so that the
segments, because every two corresponding pitch of one-half of said coils di?'ers from the
4-0
slot conductors lie in adjacent core slots, and, pitch of theother half of said coils by the
therefore, the voltage between adjacent com width between adjacent slots of said core and
mutator segments is the sum of the two volt with each slot containing corresponding slot
age differences of the two sets of correspond conductors of acoil having one pitch and a
45
50
ing slot conductors. In my armature wind
ing there is no voltage difference between two
of the corresponding slot conductors of the
coils having an end connected to adjacent
commutator segments, because they lie in the
coil having the other pitch, means for con
necting together a corresponding end of each
105
110
of said coils, and means for connecting the I
remaining ends of said coils to consecutive
commutator segments in the order in which
same slot, and, therefore, the voltage between the axes of the coils are located around said
adjacent commutator segments is only the core.
115
In witness whereof, I have hereunto set my
responding slot conductors lying in adjacent hand this 11th day of February, 1930.
HERBERT DREGHORN.
slots. It follows that in my armature wind
voltage di?erence between the other two cor
ing the voltage between adjacent commutator
segments will be one-half of thatin the prior
art armature winding. The same will be
true of the voltage between any two adjacent
commutator segments since the coils con
nected to them have slot conductors lying in
60
a common slot and slot conductors lyingin
two diiferent slots. It is evident. that the use
of my armature winding will result in a re
120
125
duction of commutation sparking with an in
85
crease of its attendant advantages.
I have described my invention in connec
130