Improvements in Dynamo
Year: 1895

page_text: Date of Application, 2nd Mar., 1895
Complete Specification Left, 2nd Dec., 1895-Accented, 15th Feb., 1896
Improvements in Dynamo ECOIN PROTON
SEBASTIAN ZIANI DE FERRANTI, 27 Charterhouse Square, in the County of
London Electrician and Engineer, do hereby declare the nature of this invention
to be as follows :-
This invention relates principally to improvements in the class of alternating
current generators or motors in which standing or revolving armatures of disc form
are made up of flat bobbins without iron cores, with field magnets rotating on each
side, or the armature rotating between field magnets, for which latter form several
Patents have been granted to me.
According to my invention I make up the bobbins in pairs with a non-magnetic
holder on each side. This 1 insulate from the bobbins with a sufficient thickness
of insulation to stand the electro motive force generated by the pair of bobbins.
These holders are pressed together with the bobbins between under very
considerable pressure and are then rivetted or screwed tightly together under this
pressure. Upon these bobbin holders I form lugs on each side by means of which
they are held to the revolving wheel. The bobbin holders act as carriers of the
current from the centre of one bobbin to the centre of the next. The other ends
of the bobbin windings are connected to metal blocks carried within the holders
and by means of insulated rivets passing through them. These blocks have a
screwed projection from one side by means of which one block is connected to the
block in the adjacent pair of bobbins, and so the continuity of the circuit of the
armature is made up by mechanical means.
In some cases I also rivet or screw a pair of plates on the outer end of the
bobbins for the purpose of keeping the bobbins and their cores more rigidly true.
These outer bobbin holders are made of non-magnetic metal and are insulated, as
above described, from the bobbins and also from adjacent holders. They are
arranged so that they register into the next set of holders thus making a continuous
registration round about the outer periphery of the armature and thus preventing
any tendency to side movement,
In some cases I put up the bobbins singly between inner bolders or between
inner and outer bolders and hold each pair separately to the wheel. The bolts
which attach the armature sections to the wheel are by preference recessed down
for a portion of their length and are covered with an insulating tube of ebonite,
mica, porcelain, or any other suitable insulator. These bolts are threaded through
holes in the rim of the armature wheel and screw into nuts iu recesses in the rim.
These recesses containing the ants are filled in with sulphur compound or some
other suitable insulating cement so that the nuts may be insulated and held rigidly
in position thus securing the bolts in like manner upon which the bobbin holders
and bobbins are carried.
One advantage of this construction is that when first the armature bobbins are
put into the machine, and before the spring has been taken out of them by ordinary
work, they need not be drawn home fully into position, the tightening up being
done after the inachine has been worked, by means of the radial insulated bolts as
above described.
In some cases bolts are screwed or fixed in the rim of the armature wheel and
the bobbins are held upon them by means of insulating washers and ferrules. In
this case the insulator must be of such a kind that it will not crush under the
centrifugal strain.

page_text: In some cases where the field magnets revolve and the armature has to stand
I make up the bobbins between holders of the same nature excepting that they are
not fitted with side lugs. They are however held by means of bolts and nuts
passing through slots in the radial surface formed of projections from heavy nuts
fixed in the recesses in a standing holder by means of sulphur as above described.
Where the insulated nuts project from the standing bolder provision is made for
surface leakage by extending the length of the insulation on the nut by means of
casting or forming an ebonite or other insulating ring round about the projecting
part. Provision is also made for wedging up the hobbins together by means of
radial screws which draw the bobbin holders down the faces of the standing nuts
and when drawn into position they may be securely held there by the bolts through
the bobbin holders into the standing nuts. In this case 1 may also make all the
bobbins in pairs and by preference I clamp the projecting ends of pairs of bobbins
between non-magnetic holders as above described. Where the armature is standing
these holders 1 register from one to another by means of a slide or pin in order
that the armature when put together may have all its parts registered in such a
manner that a continuous and rigid disc is formed.
I may also construct the machines with standing armatures with the bobbin
holders insulated by means of washers and ferrules upon bolts fixed into the ring
frame round about the magnets. In this case the bobbins are tightened up by
screwing in the nuts on the aforesaid bolts.
The important feature in my invention is carrying the hobbins and their holders
upon supports which are insulated from the main frame so that the insulation
immediately surrounding the bobbins and their hollers has not to support a higher
electro motive force than that produced by auy pair of bobbins. The main
insulation of the machine being provided in the insulation of the supports to which
the bobbins and holders are bolted.
Dated this Second day of March 1895
Improvements in Dynamo Electrical Machines.
SEBASTIAN ZIANI DE FERRANTI, 27 Charterhouse Square, in the County of
London, Electrician and 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 :—
This invention relates principally to improvements in the class of alternating
current generators or motors in which standing, or revolving armatures, of disc
form are made up of flat bobbins without iron cores, with field magnets rotating on
each side (as shown on Sheets 3, 4, and 5) or the armature rotating between field
magnets (as shown on Sheets 1 and 2), for which latter form several Patents have
been granted to me.
According to my invention I make up the bobbins in pairs (6) with a non-
magnetic holder (h) on each side. This insulate from the bobbins with a
sufficient thickness of insulation (i) to stand the electro motive force generated by
the pair of bobbins. These holders (4) are pressed together with the bobbins (6)
between, under very considerable pressure and are then rivetted or screwed tightly
together under this pressure by the rivets (r) Sheet 1.

page_text: holder in section through A. B. and the other in elevation, on C. D.
Figure 2 being a side elevation of the same one half showing elevation with the
bobbin holders cut off.
Sheet 2. Figure 3 represents a section through armature wheel (w) with bolts
secured in the rim as described.
Figure 4 side elevation showing single bobbin and holder.
Sheet 3 & 4. represents a standing armature with a revolving field F. M.
Figure 5 being a section through the frame (F) showing nut (9) as described in
section.
Figure 6 represents a side elevation of the above one half showing a pair of
bobbins without holders (h & y).
Figure 7 is the same as Fig. 5 but shows more of the revolving field and also the
nut (9) in elevation.
Figure 8 represents a side elevation of frame with the bobbins removed one half
showing the nut (g) removed.
Sheet 5 represents a standing armature the section being held to frame by
bolts.
Figure 9 being a section through the frame showing one lug washer and ferrule
in section.
Figure 10 represents a side elevation of the same.
Upon these bobbins holdors (h) I may form lugs (4) on each side by means of
which they are held to the revolving wheel (w). The bobbin holders act as
carriers of the current from the centre (e) of one hobbin (6) to the centre of the
next. The other ends (e) of the bobbin windings are connected to metal
blocks (a) carried within the holders and by means of insulated rivets (r) passing
through them. These blocks (a) have a screwed projection from one side by
means of which one block is connected to (p¹) the block in the adjacent pair of
bobbins by metal strips (s) and so the continuity of the circuit of the armature is
made up by mechanical means.
In some cases I put up the bobbins singly between inner holders or between
inner and outer holders and hold each separately to the wheel Sheet 2. The
bolts (d) which attach the armaturo sections to the wheel (w) are by preference
recessed down for a portion of their length and are covered with an insulating
tube (t) of ebonite, mica, porcelain, or any other suitable insulator. These bolts
are threaded through holes in the rim of the armature wheel and screw into
puts (n) in recesses in the rim. These recesses (9) containing the nuts (n) are filled
in with sulphur compound or some other suitable insulating cement so that the nuts
may be insulated and held rigidly in position thus securing the bolts in like manner
upon which the bobbin holders and bobbins are carried.
One advantage of this construction is that when first the armature bobbins are
put into the machine, and before the spring has been taken out of them by ordinary
work, they need not be drawn home fully in position, the tightening up being done
after the machine has been worked, by means of the radial insulated bolts as above
described.
In some cases (Sheet 2) the bolts (d) are screwed or fixed in the rim of the
armature wheel (w) and the bobbins are held upon them by means of insulated
washers and ferrules (kk). In this case the insulator must be of such a kind that
it will not crush under the centrifugal strain.
In some cases (shown on Sheets 3 & 4) where the field magnets (FM) revolve
and the arinature has to stand, I make up the bobbins (b) between holders (A) of
the same nature excepting that they are not fitted with side lugs. They are,
however, held by means of bolts and nuts, or set screws, (m) passing through slots
in the radial surface (o) formed of projections from heavy nuts (9) fixed in the
recesses (9) in a standing holder (F) by means of sulphur as above described.
Where the insulated nuts (9) project from the standing holder provision is made
for surface leakage by extending the length of insulation on the nuts by means of

page_text: casting or forming an ebonite or other insulating ring (v) round about the
projecting part of the nut (g). Provision is also made for wedging the bobbins
together by means of radial screws (r) which draw the bobbin holders (1) down
the faces of the standing nuts and when drawn into position they may be securely
held there by the screws (m) through the bobbin holders into the standing nuts (q).
In this case I may also make all the bobbins in pairs and by preference I clamp the
projecting ends of pairs of bobbins between non-magnetic holders (y) as shown in
Sheets 3 & 4.
Where the armature is standing these holders 1 register from one another by
means of a slide or pin (2) in order that the armature when put together may have
all its parts registered in such a manner that a continuous and rigid disc is
formed.
I may also construct the machines (sec Sheet 5 Figures 9 & 10) with standing
armatures with bobbin holders insulated by means of washers and ferrules (kk)
upon bolts (d), fixed into the ring frame (F) round about the magnets. In this
case the bobbins are tightened up by sorowing in the nuts (n) on the aforesaid
bolts.
The important feature in my invention is carrying the bobbins (b) and their
holders () upon supports (d) which are insulated from the main frame (W & F) so
that the insulation (i) iminediately surrounding the bobbins and their holders has
not to support a higher electro motive force than that produced by any pair of
bobbins. The main insulation of the machine being provided in the insulation of
the supports (d) to which the bobbins and holders are bolted.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is :-
(1.) In alternating current generators, making up the bobbins of the armature
in pairs and holding them between metal plates which metal plates are forced
together under considerable pressure and secured by screws or rivets.
(2.) In alternating current generators in which the bobbins are held between
metal plates carrying the said plates on bolts insulated from the metal work of the
machine.
(3.) In alternating current generators in which the bobbins of the armature are
made up in pairs and held between plates connecting the inner ends of the bobbins
together by means of plates and rivets and the outer ends to terminal blocks also
held between the plates.
(4.) Carrying armatures upon bolts, screwed or fixed in nuts which are held and
insulated in the rim of the armature wheel or in the standing frame of the
machine.
(5.) Supporting armature sections upon insulated bolts which carry the metal
clamps in which the bobbins are secured.
(6.) Where armature sections are made up of bobbins clamped between plates
supporting same upon carriers which are secured to and insulated from the body of
the machine.
(7.) Where bobbins are clamped between plates which plates are carried upon
insulated bolts providing means for drawing down the armature gradually to its
position as it contracts with use.
(8.) Where bobbins are made up between clamping plates or holders registering
from holder to holder to increase the rigidity of the holder.
(9.) My improvements in dynamo electric machines substantially as described
and illustrated.