IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Francis Heron Relph at the Office of
the Commissioners of Patents on the 19th January 1883. A Communication
to him from abroad by Joseph Olmste[a]d of the City and County of New
York State of New York United States of [North] America.
FRANCIS HERON RELPH of Basinghall Street in the City of London:
"IMPROVEMENTS IN DYNAMO ELECTRIC MACHINES." A Communication to him
from abroad by Joseph Olmste[a]d of the City and County of New York State of
New York United States of [North] America:
This Invention relates to Improvements in Magneto and Dynamo Electric
Machines whereby a very high Electro Motive force is obtained with machines of
great compactness lightness and durability.
One of the objects of this invention is to so construct the field magnets of the
machines that the armature may be readily and easily mounted in the machine or
removed for purposes of inspection or repair.
Another object of the invention is to provide an armaturo for Dynamo Electric
Machines having a number of coils wound in such manner as to give the maximum
Electro Motive force.
Another object of the invention is to increase the capacity of a Machine whereby
it is capable of producing two independent currents with a great saving of
power.
This invention consists of a bed plate or base upon which the machine is
mounted The field magnet cores and bearings for the armatures are supported by
standards which are clamped to the bed plate, four soft iron cores are mounted in
these standards in pairs. The lower pair have curved pole pieces but they are
secured in such a manner that they may be turned about said cores-Suitable
clamping bolts are used to lock the pole picces upon the cores to prevent their
being moved.
The cores are wound with coils of insulated wire, two of said coils being wound
on each core the direction of winding or the plan of connection being such as to
produce consequent poles of unlike magnetic polarity on opposite sides of the
inachine.
In the standards I arrange journals made in two parts so that the upper half
may be removed or clamped to the lower half at will.

page_text: To mount an armature in a machine thus constructed the upper portion of the
bearings are removed, the clamping bolts loosened and the upper pole pieces raised
from the lower pole picces. The pole pieces having been raised sufficiently for
swinging them around on the cores, the armaturo is mounted in position and the
pole pieces swung back into place and clamped. A great saving of time and
expense is thus effected. The Armature employed in the above described field is
cylindrical in shape and provided with a shaft of proper length, said shaft carries
one or more commutators.
The mode of winding is as follows.
A cylindrical core is wound longitudinally with five independent coils and the
inner or starting ends of said coils connected together or to the saine mass of metal,
An armature core thus wound contains 10 divisions so that in applying the coils
the most convenient plan of getting the five free ends in their proper positions
about the core is to skip one division after winding the first, skip in the same
manner another division after winding the second and so on until all the divisions
are full.
I employ in connection with said armatures a suitable commutator containing
two insulating rings or two sets of two rings in said rings or sets of rings are set
metal plates by means of which the current is taken off. On the first ring is
clamped or set a metal strip nearly or quite equal in length to half the cir-
cumference of the ring.
Lapping this on the third ring is set a similar metal strip, lapping the last
mentioned metal strip is another strip on one of the rings and also lapping the
last mentioned strip is another strip and so on to the last or outer ring.
On each pair of rings two collecting brushes press but it is evident from the
character and position of said strips that there will be a time during the revolution
of the rings that one of the brushes will not be in contact with any strip. To
prevent the break which would thus occur another strip is divided between snid
rings'so that there will always be at least one metal strip under each brush said
strips are connected together. The inner end of the coil is connected to one of
the rings and its outer end to one of the metal. strips and so on through the whole
series of strips and rings. By this arrangement the current is taken from said
rings.
This machine has therefore an electro motive force due to two full coils and
gives two currents of equal strength since the strips are in contact with the
brushes during that part of the revolution in which the coils corresponding thereto
are generating useful currents. Of the two currents thus produced one may be
used for exciting the field magnets and the other may be used for any purpose
such as running electric lamps or motors.
Instead of employing five coils as herein stated, ten or any multiple of five
may be used and wound as herein before described but five will be found the most
desirable number, this being the smallest number possible in a machine of
this kind.