Improvements in or relating to Commutators for Electric Machines.
Year: 1887

page_text: [Communicated from abroad by GEORGE WESTINGHOUSE, Junior, of Pittsburg, County
of Alleghany, State of Pennsylvania, United States of America, Engineer.]
[Communicated from abroad by GEORGE WESTINGHOUSE, Junior, of Pittsburg, County
of Alleghany, State of Pennsylvania, United States of America, Engineer.]
Improvements in or relating to Commutators for Electric Machines.
I, WILLIAM PHILLIPS THOMPSON, F.C.S. M.I.M.E. of the Agency for Foreign
Patent Solicitors 6 Lord Street Liverpool and 6, Bank Street, Manchester both in the
County of Lancaster and 323 High Holborn, in the County of Middlesex, Civil
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 :-
The object of the invention is to provide suitable means for commutating a fractional
portion of the total current derived from an alternate-current generator, for the
purpose of maintaining the magnetic field of the generator.
It is evident that if non-alternating currents are to be supplied to the field-magnets
of such a generator and derived from the alternating impulses delivered by the
armature, then the commutator must be so constructed as to reverse the connections
through the field-magnets at each reversal of the current. This is most conveniently
accomplished by placing the commutator directly upon the shaft of the armature, for
then its revolutions must necessarily coincide with those of the armature.
In the accompanying drawings, Figure 1 is a longitudinal vertical section of an
apparatus embodying the invention, and Figure 2 is a sectional view on line 2, 2, of
Figure 1, of a commutator and collecting plates embodying certain details of the
invention.
Referring to the figures, A represents the shaft of an alternate-current generator
and B', B, the two collecting rings for the two brushes b¹ b'.
These two rings are mounted upon the shaft A upon opposite sides of the
commutator C. They are insulated from the shaft by suitable non-conducting
material, such as vulcanized fibre, as shown at dd. The collecting rings are
constructed with flanges e respectively through which screws ffl and extend
into the plates c¹of the commutator C. The separate plates or divisions of the
commutator C are insulated from each other as shown at g g¹ (figure 2). They are
held in position by two projecting rings h¹ h³, which are preferably made to dove-tail
Price 621

page_text: with the plates and the sections of insulating material, and are carefully insulated
from the plates by sheets of non-conducting material as shown at i, 2. The end of
the shaft A is preferably reduced in diameter and carries a nut H by which the
rings h¹h are firmly clamped in position between the shoulder a upon the shaft and
the nut H. Each alternate-plate as c¹³, of the commutator is respectively connected
by the conducting screws ff and ƒ with the rings B₁ B². These screws serve thus
both to form the circuit connections and to secure the several parts in their proper
positions..
The contact-brushes 66 are supported in any convenient or well-known manner
from arms n' and n³ so as to bring their respective ends in contact with the
corresponding collecting rings B¹ and B².
The brushes k¹k of the commutator C are likewise supported in any convenient
manner from independent arms o' and o³. The four arms n³n, o' and o² are preferably
carried upon a frame N which is in itself adjustable as to its angular position upon
the shaft by means of a screw 0, or other equivalent mechanism.
The brushes k¹ and k² should be so set that one has the lead of the other to the
extent of one plate or division of the commutator, so that currents of opposite polarity
will be simultaneously collected by the brushes respectively.
The rectified currents from the brushes k¹k will all be of like polarity and may be
employed in any convenient manner for maintaining the magnetism of the field magnets
of the generator, or for other purposes.
It is designed that the brushes 61 and 62 shall receive their currents from the usual
collecting rings carried upon the shaft A either directly by conductors connected with
the brushes applied thereto, or through an electric converter reducing the potential of
the currents. The field is included between the brushes k¹ and k³.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me
by my foreign correspondent, I declare that what I claim is :-
--
1st. The combination with the collecting rings of an alternate-current generator, of
contact-rings receiving a portion of the current therefrom, a rectifying commutator
having its plates or sections connected alternately with the respective contact rings,
and contact brushes receiving a continuous current from the commutator.
2nd. The combination with the shaft and collecting rings of an electric generator,
said shaft having a shoulder formed upon it, of a commutator clamped against said
shoulder, and two contact-rings secured to the respective sides of said commutator.
3rd. The combination of a rectifying commutator, the shaft of an electric machine
carrying the same, two contact rings respectively placed upon opposite sides of the
commutator, flanges formed upon said rings adjacent to said commutator and screws
for clamping and connecting the respective flanges to the alternate plates of the
commutator.
4th. The combination with the shaft of an electric generator, of two contact-rings,
a commutator, contact-brushes for said ring and commutator, and a support carrying
all of said brushes, which is adjustable in its angular position with reference to
said shaft.
1
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1007
WM. P. THOMPSON & Co.,
Agents for the Applicant.