Improvements in Self Regulating Dynamo Electrio Generators and Motors.
Year: 1893

page_text: Date of Application, 28th Jan., 1898
Complete Specification Left, 28th Oct., 1893-Accepted, 2nd Dec., 1893
PROVISIONAL SPECIFICATION.
[Improvements in Self Regulating Dynamo Electrio Generators and
Motors.
We ILLIUS AUGUSTUS TIMMIS of No. 2 Great George Street, Westminster
London, S.W. Civil Engineer and ALFRED IVOR SMITH of Guilford Road,
Fleet, Hants Electrician, do hereby declare the nature of this invention to be as
follows:
:-
The objects of our invention are to provide a dynamo which shall give a constant
current with varying speeds.
With these objects in view we provide a dynamo with two fields, wound in opposite
directions, i.e. prinary & secondary. This secondary coil may consist of one or
more sections wound in parallel or series the object being to send a proportional
varying reverse current to counteract the effect of the varying current in the
primary coil due to varying speeds. The current in the secondary coil proceeds
from the dynamo itself and not from any.outside source and the number of turns
and the size of the wire in the secondary coil may be such that the main current
itself produces the necessary counter excitation to regulate the current and produce
a constant output at varying speeds or it may be regulated by means of suitable
resistances which may be operated by a governor either mechanically worked from
the prime mover or the dynamo itself or by an electrical governor worked by the
main or shunt current.
The reversal of the current is effected by a small reversing or tumbling contact
switch on or operated by the armature shaft and the reversal of the brushes may
be effected by hand or by the motion of the dynamo itself.
Dated this 28th day of January 1893.
.
I. A. TIMMIS.
ALFRED IVOR SMITH.
COMPLETE SPECIFICATION.
Improvements in Self Regulating Dynamo Electric Generators and
Motors.
We ILLIUS AUGUSTUS TIMMIS of No. 2 Great George Street, Westminster
London S.W. Civil Engineer and ALFRED IVOR SMITH of Guilford Road,
Fleet, Hants, Electrician 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 objects of our invention are to provide a dynamo which shall give a constant
current with varying speeds.
With theso objects in view we provide a dynamo with two fields, wound in
opposite directions, i.e. primary and secondary. This secondary coil may consist of
one or more sections wound in parallel or series the objects being to send a
proportional varying reverse current to counteract the effect of the varying current
in the primary coil due to varying speeds. The current in the secondary coil
proceeds from the dynamo itself and not from any outside source and the number
of turns and the size of the wire in the secondary cell may be such that the main
current itself produces the necessary counter excitation to regulate the current and
produce a constant out-put at varying speeds or it may be regulated by means of
suitable resistances which may be operated by a governor either mechanically

page_text: worked from the prime mover or the dynamo itself or by an electrical governor
worked by the main or shunt current, or by hand.
The reversal of the current is effected by a small reversing or tumbling contact
switch on or operated by the armature shaft and the reversal of the brushes may
be effected by hand or by the motion of the dynamo itself.
The dynamo may be wound with the fine wire shunt on one leg, with or without
a variable resistance and the main current wire on the other wound in a reverse
direction, the fine shunt may be divided on the two legs, and the main wire as well,
or it may be wound with the fine shunt on one leg and the main wire on the other-
and with a fine auxiliary shunt on same leg as main wire, with or without an
adjustable resistance operated either automatically by the speed of the train or by
hand, the reversing of the brushes is effected by hand or by the movement of the
dynamo itself while the reversal of the current is effected by a switch on or operated
by the shaft of the dynamo.
Fig. 1. a is the main circuit + wiro, b the negative main circuit wire, c the
shunt or exciting wire, d the resistance, e the armature, the brushes.
The circuit a is wound round one leg of the magnet in a reverse direction to the
exciting circuit c and the circuit a is closed only when the E.M.F. induced by cis
at the determined point, the further increase of voltage caused by e owing to the
increase of speed is counteracted by the demagnetizing power of a acting against c,
a variable resistance d may be inserted to assist or regulate the voltage which may
be worked automatically or by hand.
Fig. 2. shows a modification of Fig. 1. where thore is an auxiliary demagnetizing
shunt g with or without variable resistance & worked as before.
The reversing of the whole of the currents necessary when the direction of
rotation of the armature is reversed is effected by a reversing switch operated by
hand or by a switch operated on or by the spindle of armature.
In either Fig. 1, or Fig. 2, the shunts and main circuits may be wound one on
cach leg as shown or may be divided ou both.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
In dynamo electric generators and motors working at varying speeds the method
of regulating the same with the object of providing a constant out-put by means of
reverse currents circulating in separato coils on the field magnets substantially as
described, and shown.
DL:- no 1000