IMPROVEMENTS IN MEANS AND APPARATUS FOR PREVENTING EXCESSIVE HRAT IN DYNAMO ELECTRIC MACHINES
Year: 1883

page_text: LETTERS PATENT to Henry Roberts, Engineer, of Pittsburgh, in the County of
Allegheny and State of Pennsylvania, one of the United States of America for
an Invention of "IMPROVEMENTS IN MEANS AND APPARATUS FOR PREVENTING
EXCESSIVE HRAT IN DYNAMO ELECTRIC MACHINES"
PROVISIONAL SPECIFICATION left by the said Henry Roberts at the Office
of the Commissioners of Patents on the 24th April 1883.
"E
HENRY ROBERTS, Engineer, of Pittsburgh, in the County of Allegheny and
State of Pennsylvania, one of the United States of America, IMPROVEMENTS IN
MEANS AND APPARATUS FOR PREVENTING EXCESSIVE HEAT IN DYNAMO ELECTRIC
MACHINES"
I have conceived and successfully reduced to practice a plan of cooling the parts
of a dynamo machine which tend to become intensely heated, by providing one or
more strong currents of air generated by a suitable blower, and directing it or
them upon the heated parts with liberty to be spread and distributed therefrom
in all directions. In what I esteem the most complete form of the invention, I
blow on the field magnets, and also on the revolving armature with three strong
blasts.
The dynamo machine may be of the Brush style, with its revolving armature,
field magnets, and helices for the latter. I'blow upon them with one nozzle from
above, and with two nozzles from opposite sides, all directed radially inward
towards the axis... The blast for the whole is produced by a single blower, and is
led through a trunk pipe and three branches therefrom, one branch leading to each
nozzle. The temperature is, in consequence, maintained at.a low. point.
The invention contributes to the uniformity of generation of electricity, and
especially to the production of the required quantity of current, with a moderate
velocity of rotation of the armature.. The invention saves the parts from the
destructive effects due to the ordinary high temperature.

page_text: •
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Henry Roberts in the Great Seal Patent Office on the 23rd October
1883.
HENRY ROBERTS, Engineer, of Pittsburgh, in the County of Allegheny, and
"IMPROVEMENTS IN
State of Pennsylvania, one of the United States of America,
MEANS AND APPARATUS FOR PREVENTING EXCESSIVE HEAT IN DYNAMO ELECTRIC
MACHINES"
I have conceived and successfully reduced to practice a plan of cooling the parts
of a dynamo machine which tend to become intensely heated, by providing one or
more strong currents of air generated by a suitable blower, and directing it or
them upon the heated parts with liberty to be spread and distributed therefrom
in all directions. In what I esteem the most complete form of the invention, I
blow on the field magnets, and also on the revolving armature with three strong
blasts.
The dynamo machine may be of the Brush style, with its revolving armature,
field magnets, and helices for the latter. The motion of the armature generates
electricity which is desired, and is usefully disposed of. In addition to that, it
generates heat which is not desired, and which it is the object of my invention to
dispose of.
Ordinarily, the heat accumulates in the parts until it reaches a temperature at
which it will escape by radiation, and by natural convection to the surrounding
air which is at rest except the slight motion induced by the revolution of the
armature.
It has been proposed, and I believe attempted, to cool the parts by currents of
water circulated through pipes and passages in the revolving armature, and also in
the field magnets. Such plan is objectionable for many reasons.
I blow on the field magnets, and also on the revolving armature in sufficiently
strong blasts, and so distributed that the temperature is maintained at a low point
under all conditions.
My invention contributes to the uniformity of the generation of electricity, and
especially to the production of the required quantity of current with a moderate
velocity of rotation of the armature. The uniformity of current saves the carbons;
the reduction of the velocity saves the brushes, and the direct cooling by the blast
of air applied to the revolving armature saves this part of the apparatus, especially
the spools, from the destructive effects of high temperature.
The following is a description of what I consider the best means of carrying out
the invention. The accompanying drawings form a part of this specification.
Figure 1 is a perspective view, and
Fig. 2 a plan.
Similar letters of reference indicate like parts in both the figures. The drawings
represent the novel parts, and so much of the ordinary parts as is necessary to
indicate their relation, thereto. The ordinary parts need not be described
minutely.
A is the fixed frame-work, B the field magnets, and D the revolving armature
mounted on a shaft, and powerfully revolved at the proper speed by the aid of a
belt, not represented, running on the pulley D. All these parts may correspond
exactly with the ordinary arrangement in the Brush Dynamo Machine.
M is a rotary fan-blower driven at the required high velocity by the same
power which drives the dynamo, or by any other. It receives atmospheric air at
the ordinary temperature, and blows it through a pipe P to the immediate vicinity

page_text: It is represented as being led across the principal portion of the room. Other
situations may serve.
One
Three branches P1, P2, P³, extend from this pipe P, and lead the air in smoothly
directed currents, and direct them upon the parts liable to be heated.
pipe, P', blows the air upon the revolving armature D in the radial direction.
Another branch, Ps, leads the current down between the helices, and projects the
current of air against the revolving armature in a direction nearly or quite parallel
to the axis. The third, P³, correspondingly directs a blast against the opposite
side of the armature D. The streams projected by the branches P2 and P3 should
not be in the same line, but in lines parallel to each other in opposite directions,
as indicated in Fig. 2.
Modifications may be made in the details.
The invention may be applied to other dynamo machines than those of the
Brush pattern.
The pipe P may be conveniently placed over-head, as shown, when the
mechanisin is already completed and in place. But for new machinery, the pipes
may be beneath the floor, the branches P1, P2, P3, coming up through the bed-plate
in suitable positions to blow, substantially as shown.
Parts of the invention may be used without the whole.
I claim as my invention :-
1st: The combination with a dynamo electric machine, of a blowing machine M,,
and provisions for directing one or more currents of air therefrom upon the parts
which are likely to be heated, and which are un-enclosed, whereby the heated air
is allowed to escape freely in all directions from the heated surfaces, substantially
as herein specified.
2d: The revolving armature D, field magnets B, blast nozzles P1, P2, P³, trunk
pipe P, and blower M, combined and arranged for joint operation, as herein
specified.
°
In witness whereof, I, the said Henry Roberts, have hereunto set my hand and
seal, the Twenty fith day of September, One thousand eight hundred and eighty-
three
Witnesses.
WILLIAM HENRY ROBERTS
JOHN BOOTH
HENRY ROBERTS (L.S.)