Improvements in Dynamo Machines.
Year: 1890

page_text: Date of Application, 7th Oct., 1890
Complete Specification Left, 1st July, 1891-Accepted, 19th Sept., 1891
PROVISIONAL SPECIFICATION.
Improvements in Dynamo Machines.
I, WILLIAM FALCONER KING, of King Brown & Co., Rosebank Electric
Works, Edinburgh, in the County of Midlothian, North Britain, Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
:-
According to my invention the magnets and their excitation are so arranged that
the friction is reduced. For instance, in a four pole machine with vertical magnets
I make the field stronger at the top than at the bottom, so that the magnetic pull
counteracts the weight of the armature. This arrangement I especially prefer for
direct driving, as the lower magnets can then be made shorter, so that the centre
of the machine is lower, which is of considerable importance. If the armature is
wound so as to be in series, the vertical pull is obtained by using greater total
induction on the upper side of the armature; if the armature is wound parallel, as
usual, I use the same total induction above as used below, but I make the pole
surfaces smaller. As the force per square inch varies as the square of the induction,
I thus get the vertical pull without developing more electro-motive force on one
side of the armature than the other. When the magnets are horizontal instead of
vertical, I make the upper pole surfaces less than the lower, thus taking the weight
of the armature off the bearings.
I also, when advisable, arrange the excitation of multipolar machines so that I
get a long range for compounding. One or more of the magnets is designed so as
to be fairly saturated by the shunt excitation at no load, the other or others is or
are excited to a large extent by series winding. I thus avoid the tendency to
instability so common at light loads in machines which run at small speeds or
compound up much. This arrangement may be combined with the uneven field
disposition already described, being produced in the same way, or may be used
without unevenness of field at full load. A similar arrangement is useful in arc
light machines which are automatically regulated through large ranges.
magnet circuit is excited by the current proper, and another, or the others are
excited with a regulating resistance in shunt, so that the machine, even on a few
lamps, is not unstable.
Dated this 6th day of October 1890.
One
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.
COMPLETE SPECIFICATION.
Improvements in Dynamo Machines.
I, WILLIAM FALCONER KING, of King Brown & Company, Rosebank Electric
Works, Edinburgh, in the County of Midlothian, North Britain, 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 :-
According to my invention the magnets and their excitation are so arranged that
the friction is reduced. For instance in a four pole machine with vertical magnets
I make the field stronger at the top than at the bottom so that the magnetic pull
counteracts the weight of the armature. This arrangement I especially prefer for
direct driving, as the lower magnets can then be made shorter so that the centre of
the machine is lower which is of considerable importance. If the armature is
wound so as to be in series, the vertical pull is obtained by using greater total

page_text: induction on the upper side of the armature; if the armature is wound parallel, as
usual, use the same total induction above as used below, but 1 make the pole
surfaces smaller. As the force per square inch varies as the square of the
induction per square inch, I thus get the vertical pull without developing more
electro-motive force on one side of the armature than the other. When the magnets
are horizontal instead of vertical I make the upper pole surfaces less than the
lower, thus taking the weight of the armature off the bearings.
I also when advisable arrange the excitation of multipolar machines so that I
get a long range for compounding. One or more of the magnets is designed so as
to be fairly saturated by the shunt excitation at no load, the other or others is or
are excited to a large extent by series winding. I thus avoid the tendency to
instability so common at light loads in machines which run at small speeds or
compound up much. This arrangement may be combined with the uneven field
disposition already described being produced in the same way, or may be used
without unevenness of field at full load. A similar arrangement is useful in arc
light machines which are automatically regulated through large ranges.
magnet circuit is excited by the current proper, and another or the others are
excited with a regulating resistance in shunt, so that the machine even on a few
lamps is not unstable.
One
The drawing represents an elevation of the magnets of a four pole dynamo,
A, B, C, and D being the four magnets. The lower magnets A and B are made
shorter than the upper ones C and D, so that the field may be stronger above than
below the armature. The upward magnetic pull counteracts the weight of the
armature.
If the armature is wound parallel I make the pole surfaces smaller above than
below. This may be done by allowing the pole pieces above to terminate at the
dotted lines a, b, c, d.
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 a multipolar dynamo machine in which the armature is wound so as to
be in series the construction of the magnets so as to obtain greater total induction
above than below, as and for the purposes described.
2. In a multipolar dynamo machine in which the armature is wound parallel the
construction of the upper pole surfaces of smaller area, as and for the purposes
described.
3. In compound wound multipolar dynamo machines the construction of one or
more of the magnets so as to be fairly saturated by the shunt excitation at no load
while the other or others is or are excited to a large extent by the series winding,
as and for the purposes described.
Dated this 30th day of June 1891.
BOTTOMLEY & LIDDLE,
154, St. Vincent Street, Glasgow, Applicant's Agents.