DYNAMO ELECTRIC MACHINES
Year: 1885

page_text: I JAMES SWINBURNE of 3 Fairfield Villas Chelmsford, Essex, Electrician do
hereby declare the nature of my invention for DYNAMO ELECTRIC MACHINES, to
be as follows: —
My invention relates to dynamos and motors with very intense fields between
poles of opposite polarity. According to my invention a dynamo has its poles
arranged as in the well known Hefner Alteneck or Ferranti alternating current
machines, but the armature and commutator are so arranged as to give direct
currents. The machine may have any convenient even number of pairs of poles:
If it has two pairs of poles it may have three or five coils. One set of ends of the
coils are joined together and the other ends are led to three or five segments
forming the commutator. Two brushes collect at opposite sides, and these brushes
are broad enough to bridge well over the insulation between the segments. By
this means generally two of the three coils are working in series & the third is
idle, but while the brush touches two segments two coils are in parallel with each
other, & together in series with the other. The brushes may be made broad enough,
or the commutator segments may be cut obliquely to prolong this. Five coils work
similarly.
If the machine has four pairs of poles, 5 is a good number of coils. Ten
segments are needed, with the brushes at right angles & the opposite segments
connected together so that four brushes are not needed. If the machine has a
large number of poles and coils the coils may be arranged in sets of three. Thus a
nine coil armature has three sets of coils, each coil of a set being 120° from the
others. Each set has then its own commutator, & brushes, & the sets may be thus
connected up in parallel or series, or used separately.
;
If the number of coils is even the coils may be arranged in continuous circuit
so that the armature is like an alternating machine armature with its circuit
completed.
The segments are connected to the joints of the ends of the coils. This
arrangement is only applicable when the numbers of coils and pairs of poles have
a small greatest common measure. It is best when the numbers differ by 2. It is
inapplicable to an odd number of armature coils, as every alternate coil must be
reversed; and an odd number of coils is preferable.
The pole pieces should be of suitable width, and the armaturè coils as numerous
as possible so as still to be as broad as the poles. The sides of two neighbouring
coils should be close, not separated an angular distance about equal to the angular
breadth of the coils.
Of course these arrangements are applicable to motors and magneto machines.
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page_text: I, JAMES SWINBURNE of 3 Fairfield Villas, Chelmsford, Essex do hereby declare
the nature of my invention for DYNAMO ELECTRIC MACHINES and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
My invention has for its object the practical making of dynamos with very
narrow armature coils moving in very strong fields between poles of opposite
polarity, so arranged as to give continuous currents.
I prefer to use as few poles as possible, so that the commutator may be simple
and the fields strong with small expenditure of power, and I prefer to make the
armature coils of strip copper wound into flat coils which are thus very narrow.
For most purposes I prefer to have four pairs of field poles. Thus the field
magnets are heavy and the poles are brought close together, and the pole pieces
are designed to make the fields between the poles as uniform as possible. The
armature consists of flat coils mounted on a hub so as to pass edgeways between
the poles. If three coils are used three of the six ends of the coils are connected
together and the other three are joined to a six part commutator, each end being
joined to two of the six segments. Two brushes are used. By this arrangement,
calling the coils 1, 2, & 3, the current goes, say, in at 1 & out at 2; then in at
1 & 3 in parallel and out at 2; then in at 3 & out at 2; then in at 3 & out at
2 & 1 in parallel, and so on.
Instead of 3 coils 5 may be used in the same way,
with 10 segments. For some purposes the dynamo may have only 2 pairs of poles
and 3 or 5 coils and segments. A 9 coil armature may be arranged in 3 sets of
3 coils with three commutators and. six brushes, so that the three sets are in
series.
In the accompanying drawings, which are meant to be diagrams only, Fig. 1
shews a three coil armature in a two pole dynamo. ab are the faces of the poles,
cde the coils, f, g, h the segments & ik the brushes. The best way to get a clear
idea of the action is to make a tracing of the armature & turn it round over a
sketch of the pole faces with arrows marked on to shew the direction of the
induction.
In fig. 2 a three coil armature is shewn in a four pole dynamo, that is to say a
dynamo with four pairs of poles. The opposite commutator segments are connected.
Fig. 3 is a five coil armature in a four pole dynamo.
Fig. 4 is a nine coil armature in an eight pole, machine. Only three of the nine
coils are shewn, the joined ends being connected as usual round the outside, and
the other ends to a 12 part commutator. There are three sets of coils, & three
commutators, which are connected in series. Fig. 5 shews a commutator, for a
nine coil armature, for connecting the coils in parallel.
Instead of shewing the cross connections the segments are numbered, those with
the same number being connected together.
Fig. 6 shews aithree coil armature for a two pole machine. a, b, c are the flat
coils and d is a strengthening rim.

page_text: The coils are held in recesses in the bosses e e, shewn in section in fig. 7. The
thick black lines represent insulating material.
Fig. 8 represents a 5 coil armature for a six pole machine.
Fig. 9 is a 3 coil armature for a four pole machine.
Fig. 10 is a 9 coil machine for high tension with 10 poles. Fig. 11 is another
view of it. a is the rim; b, c, d, e, f coils; g, h, i, j, k, l, magnet faces; m hub;
n,, 8 commutators; o, p, brushes; q connections coming through hollow shaft
t field coils.
;
Fig. 11 shews a method of rounding off the corners of the field magnets to prevent
Foucault currents when the armature coils are iron.
<<
By dynamo" in this specification I mean of course either a generator or
motor.
Having now particularly described & ascertained the nature of my said inven-
tion, and what manner the same is to be performed, I declare that what
I claim is
1. In a dynamo of the kind described an armature having one more coil than
there are pairs of poles.
2. In a dynamo of the kind described an armature having one coil fewer than
there are pairs of poles.
3. In a dynamo of the kind described with two pairs of field poles 3 or 5 coils
with one set of ends joined together and the others joined to a 3 or 5 part
commutator as described.
4. In a dynamo of the kind described with four pairs of field poles 3 or 5 coils
with one set of ends joined together and the others joined to a six or ten part
cominutator substantially as described.
5. A dynamo with 4 pairs of poles & 3 flat coils, of the kind described.
6. A dynamo with 4 pairs of poles & 5 flat coils, of the kind described.
7. A dynamo with 4 pairs of poles & 3 flat coils of which one set of ends are
joined together substantially as described.
8. A dynamo with 4 pairs of poles & 5 flat coils of which one set of ends are
joined together substantially as described.
9. A dynamo of the sort described with its coils in sets with their own commu
tators which can be connected up in series or parallel.
Dated this 22nd day of December 1885.