Improvements in or relating to Armatures for Dynamo Electric Machines, Electric Transformers, and the like.
Year: 1893

page_text: Date of Application, 28th Mar., 1893
Complete Specification Left, 29th Jan., 1894-Accepted, 28th Mar., 1894
PROVISIONAL SPECIFICATION.
Improvements in or relating to Armatures for Dynamo Electric
Machines, Electric Transformers, and the like.
I, JOHN GRICE STATTER, of 68 Victoria Street, Westminster, in the County
of Middlesex, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
My invention relates to improvements in armatures employed in what are known
as dynamotors, motor-dynamos or continuous current transformers, but which I
shall hereinafter refer to as transformers.
The present approved practice in building dynamo machines of the drum
armature type is to make the armature shorter than was formerly the rule and to
provide a space between the spindle and the discs (so called) for the purpose of
ventilation.
With such armatures the requisite amount of sectional area of iron is readily
obtained even with a considerable internal space, so that a modern drum armature
core somewhat resembles a ring armature core of unusual radial depth of ring. It
would be impracticable to wind such an armature core in the usual ring (Gramme)
fashion, because the internal periphery of the ring is small as compared with the
external; and even by resorting to placing more layers of wire internally than
externally not more than about half the conductor which could be got comfortably
upon the external surface could be accomodated in the internal space. Such cores
are therefore in practice wound in drum fashion, that is to say in the Sturgeon, or
as it is more frequently termed the Siemens, method of winding in which the
conductors pass across the ends of the armature and appear on the side opposite to
that upon which their winding was commenced.
By winding in this manner considerable space is taken up at both ends of the
armature and the distance between the bearings of the armature has to be con-
In the manufacture of
siderably greater than for Gramme wound armatures.
transformers this length of spindle (or in other words of armature) between
bearings is important since there are two commutators to be provided for.
If the armture is wound on the Siemens plan it becomes impracticable to design
a bed-plate which shall properly accomodate at will either a drum armature dynamo
or a transformer with drum armature, since a bed-plate suitable for the latter
On the other
would be too long for the former by the length of a commutator.
hand a bed plate designed to accomodate a ring wound transformer armature might
be too short for a drum wound dynamo armature.
To overcome this difficulty and at the same time to obtain an armature wherein
the primary and secondary coils are more effectually insulated from one another
than has heretofore been the case I wind my primary coils in Gramme fashion
and my secondary coils in Sturgeon or Siemens fashion (or vice versa) upon the
same core.
Those coils which are wound in Siemens fashion only take up half the space
lengthways at the ends which is taken up by the Sturgeon or Siemens winding of
the same core wound as a dynamo, and the space so saved is enough for the extra
commutator required.
By means of this invention I am enabled to design a machine with magnets, bed-
plate, bearings and armature core which can be adapted for the purpose of serving

page_text: efficiently either as a dynamo or as a motor or as a continuous current transformer,
according mainly as the said armature core may be wound.
Dated this 27th day of March 1893.
J. G. LORRAIN, M. Inst. E.E., M. Inst. M.E.,
Norfolk House, Norfolk Street, Strand, London, W.C.,
Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improvements in or relating to Armatures for Dynamo Electric
Machines, Electric Transformers, and the like.
I, JOHN GRICE STATTER, of 68 Victoria Street, Westminster, in the County
of Middlesex, Electrical 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 invention relates to improvements in armatures employed in what are known
as dynamotors, motor-dynamos or continuous current transformers, but which I
shall hereinafter refer to as transformers.
The present approved practice in building dynamo machines of the drum
armature type is to make the armature shorter than was formerly the rule and to
provide a space between the spindle and the discs (so called) for the purpose of
ventilation.
With such armatures the requisite amount of sectional area of iron is readily
obtained even with a considerable internal space, so that a modern drum armature
core somewhat resembles a ring armature core of unusual radial depth of ring. It
would be impracticable to wind such an armature core in the usual ring (Gramme)
fashion, because the internal periphery of the ring is small as compared with the
external; and even by resorting to placing more layers of wire internally than
externally not more than about half the conductor which could be got conveniently
upon the external surface could be accommodated in the internal space. Such
cores are therefore in practice wound in drum fashion, that is to say in the Sturgeon
or as it is more frequently termed the Siemens method of winding in which the
conductors pass across the ends of the armature and appear on the side opposite to
that upon which their winding was commenced.
By winding in this manner considerable space is taken up at both ends of the
armature and the distance between the bearings of the armature has to be con-
siderably greater than for Gramme wound armatures. In the manufacture of
transformers this length of spindle (or in other words of armature) between
bearings is important since there are two commutators to be provided for.
If the armature is wound on the Siemens plan it becomes impracticable to
design a bed-plate which shall properly accommodate at will either a drum
armature dynamo or a transformer with drum armature, since a bed-plate suitable
for the latter would be too long for the former by the length of the commutator.
On the other hand a bed-plate designed to accommodate a ring wound transformer
armature might be too short for a drum wound dynamo armature.
To overcome this difficulty and at the same time to obtain an armature wherein
the primary and secondary coils are more effectually insulated from one another
than has heretofore been the case I wind my primary coils in Gramme fashion
and my secondary coils in Sturgeon or Siemens fashion (or vice versa) upon the
same core.
Those coils which are wound in Siemens fashion only take up half the space
lengthways at the ends which is taken up by the Sturgeon or Siemens winding of
the same core wound as a dynamo and the space so saved is enough for the extra
commutator required.

page_text: By means of this invention 1 am enabled to design a machine with magnets, bed--
plate bearings and armature core which can be adapted for the purpose of serving
efficiently either as a dynamo or as a motor, or as a continuous current transformer
according mainly as the said armature core may be wound.
In the accompanying drawings I show one way of carrying my invention into.
effect.
Figure 1 is a diagrammatic view of an armature core as seen end on with only a
few turns of wire upon it.
Figure 2 is an elevation partly in section of a rotary transformer armature and
commutators.
A is the armature shaft and B, B' are the two commutators. b, b₁ are commutator
bars. C shows a part of the armature core in section. D is the ring winding and
E the drum winding. F indicates the insulation covering the ring winding and
eud connections.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:
1. In an armature for dynamo-electric machinery the combination of a ring and.
a drum winding substantially as set forth.
2. The method of economising space in connection with an armature substantially
as set forth.
3. In the armature of a rotary transformer the combination of a Gramme
primary winding and a Sturgeon secondary winding, or vice versa a Sturgeon
primary winding and a Gramme secondary winding substantially as set forth.
Dated this 29th day of January 1894.
For the Applicant,
J. G. LORRAIN, M.I.E.E., M.I. Mech. E.,
Norfolk House, Norfolk Street, Strand, London, W.C.,
Chartered Patent Agent,