Method or Means of Regulating Motor-dynamos or Continuous Current Transformers.
Year: 1889

page_text: Date of Application, 27th Sept., 1889
Complete Specification Left, 27th June, 1890-Accepted, 16th Aug., 1890
PROVISIONAL SIECIFICATION,
Method or Means of Regulating Motor-dynamos or Continuous
Current Transformers.
I, WILHELM LAHMEYER, Electrical Engineer, of Aix-la-Chapelle, in the German
Einpire, do hereby declare the nature of this invention to be as follows:-
If, in a motor-dynamo, that is to say, in a continuous current transformer, the
motor winding and the movable current generator winding are mounted on the
same armature, owing to. which arrangement a single machine frame only need
be used, certain advantages are obtained as regards the self-induction of the armature
conductors, the useful effect and the cost of construction of the machine.
However, this construction is suitable only for motor-dynamos, the two halves of
which work symmetrically; that is, either with the same quantity of current, or with
the same tension, and consequently hitherto only in conjunction with cumbersome and
complicated regulating arrangements which employ artificial resistances.
The case which I have in view is that of motor dynamos working in parallel and
with a secondary circuit of constant tension. For the sake of brevity I will designate
the motor dynamo with M D. The difficulty which the necessary regulation
encounters in this case, will appear from the following considerations ;-The tension
at the primary terminals of the M D is given. The counter electro-motive force of
the motor winding of the armature should slightly diminish from the working without
load, to the working of the machine with full load, in order that the current of the
armature in question may increase proportionately to the load, and if under these
conditions, the number of revolutions is required to remain constant, the diminution
of this electro-motive force must be produced by a corresponding decrease of the active
magnetism. On the other hand, in the motor dynamo, the winding of the armature
that supplies the current, requires, as in all machines with constant potential, that the
electro-motive force shall increase when the load increases.
Now, as the two electro-motive forces are always proportional, their inverse varia-
tion cannot be produced by varying their magnetism. By using suitable resistance
regulators, either in the primary or in the secondary circuit of the M 1, the tension
may be equilibrated as required, but regulators of this system do not act with certainty
and precision, and none of them is economical.
According to my invention, I employ, (instead of these regulating resistances) the
electro-motive force of a special dynamo, which, owing to a suitable method of winding
keeps the tension automatically in equilibrium.
For the sake of brevity I will call this regulating dynamo R D. Its armature may
be driven from the shaft of the motor-dynamo, either directly or by intermediate
gear or from any other moving part. The field magnet winding of the R D is
included in one of the circuits starting from the collectors of the current generator
winding of the motor dynamo; and its armature may also be included in
one of these generator circuits, so as to produce a tension which assists the current in
this circuit; or its armature may be placed in series with the motor winding of
the main arinature so as to produce a tension that assists the tension supplied to the
motor, in order to regulate the tension at the terminals of, the secondary winding of
the motor-dynamo.
In a machine such as that described above, that is a motor-dynamo for working
in parallel, in which the motor winding and the current generator winding are
mounted on the same ring, the circuit of one of the two windings may include
the winding of a second armature ring smaller than the main ring, and mounted.
on the same shaft; this second armature being influenced by a magnetic field, the
coils of which are included in the main circuit of the current generating half o.

page_text: the machine, in such a manner that the tension produced in this auxiliary ring
increases the tension that is supplied to the inetor winding if the latter controls the
ring; or that the tension produced in this ring assists the tension supplied by the
current generator winding, if this latter tension controls the ring, in order to regulate
the secondary tension at the terminals of the dynamo.
Dated this 27th day of September 1889.
W. LAHMEYER.
By Fairfax & Wetter,
Agents.
COMPLETE SPECIFICATION.
Method or Means of Regulating Motor-dynamos or Continuous
Current Transformers.
1, WILHELM LAHMEYER, Electrical Engineer, of Aix-la-Chapelle, in the German
Empire, do hereby declare the nature of this invention and in what manner the same
is to be performed, to be particularly described in and by the following statement:-
If, in a notor-dynamo, that is to say, in a continuous current transformer, the
motor winding and the movable current generator winding are mounted on the same
armature, owing to which arrangement a single machine frame only need be used,
certain advantages are obtained as regards the self-induction of the armature
conductors, the useful effect and the cost of construction of the machine.
However, this construction is suitable only for motor-dynamos, the two halves of
which work symmetrically; that is, either with the same current, or with the same
pressure, and consequently hitherto only in conjunction with cumbersome and com-
plicated regulating arrangements which employ artificial resistances.
The case, which I have in view, is that of motor dynamos working in parallel and
with a secondary circuit of constant tension. For the sake of brevity, I will designate
the motor dynamo with M D. The difficulty which the necessary regulation
encounters in this case, will appear from the following considerations;-The tension
at the primary terminals of the M D is given.. The counter electro-motive force of
the motor winding of the arinature should slightly diminish from the working without
load, to the working of the machine with full load, in order that the current of the
armature in question may increase proportionately to the load, and if under these
conditions, the number of revolutions is required to remain constant, the diminution
of this electro-motive force must be produced by a corresponding decrease of the active
magnetism. On the other hand, in the motor dynamo, the winding of the armature
that supplies the current, requires, as in all machines with constant potential, that the
electro-motive force shall increase when the load increases.
Now, as the two electro-motive forces are always proportional, their inverse variation
cannot be produced by varying the magnetism of the M. D. By using suitable
resistance regulators, either in the primary or in the secondary circuit of the M D, the
tension may be equilibrated as required, but regulators of this system do not act with
certainty and precision, and none of them is economical.
According to my invention, I employ, (instead of these regulating resistances) the
electro-motive force of a special dynamo, which, owing to a suitable method of winding,
keeps the tension automatically in equilibrium.
For the sake of brevity, I will call this regulating dynamo R D.
Figs. 1 shows a M D'with this kind of regulation. The two concentric circles A, A.,
represent the armature with motor winding and current generator winding. The field
winding is shown as a shunt n from the motor terminals I, II. But the arrangement
is not essential, as I may employ any field winding adapted to work a parallel motor
at an approximately constant number of revolutions.
It is evident, that the electro motive force produced in A. decreases with the load
on the motor-dynamo, whereas the contrary ought to take place. To obtain the
necessary compensation of pressure, I place a series-wound auxiliary dynamo R D in
one of the generator circuits, as shown by the drawing, and drive it from the shaft

page_text: of the M D or from another suitable source of power at a constant speed (as constant
as possible) and in such a direction, that its electro motive force will be added to that
of the generator winding A.. By means of a suitable winding and speed of the R D,
I can therefore easily ensure, that the secondary tension of the M D, namely that at
the terminals III and IV, remains constant, provided that the pressure supplied to the
terminals I and II remains constant.
The armature RD may be mounted on the shaft of the main armature, in which
case no separate brushes or collectors are required for the R D, as the current generator
winding may be continued directly over the armature of the RD, without having a
collector or commutator between the two armatures. Fig. 2 shows this arrangement.
A is the main armature, R the regulating armature.
The field winding e belonging
to the latter lies behind one of the secondary collectors in one of the lighting circuits.
The motor winding of the armature is indicated by dotted lines, and the current
generator winding by full lines. The other letters, and the method of action corre-
spond exactly to those described in reference to Fig. 1. Also in this case, the large
field magnets may be wound differently.
The method of regulation may be modified as follows:-Instead of increasing the
tension of the current generator winding by means of an auxiliary tension, as the load
increases, I may reduce the counter electro-motive force of the motor winding, as the
load increases, by the tension of a regulating armature acting in the opposite sense.
By this means, the current in this winding is increased, the armature of the M D runs
faster, without requiring any reduction of its magnetism.
I therefore arrange the different parts in such a manner, that in consequence
of this action, or, while keeping the speed constant, by an increase of this magnetism,
the MD is regulated for constant tension at the secondary terminals.
Fig. 3 shows this arrangement with an independent R D. The meaning of the
letters corresponds to that adopted in the previous figures. The regulating armature
is placed in series with the motor winding A¹ of the main armature between the
terminal I and II, at which the motor is supplied with constant electric tension. In
the same sense as this tension, acts also the tension of the armature R, but A¹ generates
a counter tension. Now, as the field of the R D is excited by a winding ee situated
in one of the circuits starting from the brushes of the current generator winding A₁,
the auxiliary tension in R, and consequently the current of the motor winding A,
increases as the load on the M D increases, which is necessary for the purpose of
regulation. The R D would therefore have to be driven from the shaft of the M D,
as in Fig. 1, or from any other suitable source at a constant speed (as constant as
possible).
If the armature R is mounted on the same shaft as the armature of the
windings A, and A₂, the notor winding may also in this case be carried directly over
both armatures.
This arrangement is represented by Fig. 4, in which the letters correspond to those
of the previous figures.
The inotor winding, which in this case extends over R and A, is again represented
by dotted lines, and the generator winding by full lines. The auxiliary tension pro-
duced in the armature R acts in this case, as mentioned above, against the tension of
the same winding produced in the armature A, that is to say, in the direction of the
tension supplied to the terminals I and II. The field magnets belonging to R are
again excited by a direct winding ee of the lighting circuit, so that, with the load on
the M D increasing, the motor winding of the armature receives more current, as is
required, without necessitating a decrease of the magnetism of the large field magnets,
the same as has been described with reference to Fig. 3.
In the arrangements represented by Figs. 3 and 4, the manner of exciting the field
of the M D may also be varied. In all cases it is possible, to employ a direct winding
of the current generator half of the machine.
In Figs. 3 and 4 this winding may be arranged to act in the same sense as n, in
Figs. 1 and 2, it would act in the opposite direction.
It is also possible, to excite the field of the M D by a third and separate winding of

page_text: the large armature, or by a separate dynamo. All these modifications would not affect
the principle of the invention. The regulation may also be modified in the following
manner:
Supposing that an M D with both windings on the same armature, produces, when
fully loaded, exactly the desired secondary tension.
In this case the latter increases beyond the desired limits when the load decreases.
We may now arrange an R D in such a manner, that the regulating armature absorbs
this excess of tension. In this case, the effect of the R D would correspond to the
action of a dynamo with differential winding, as described in my patent specification
No. 18,7841888. The R D would likewise have a constant shunt winding acting
as exciter and a demagnetising direct winding. I may also arrange the RD with
differential winding and motor action in the circuit of the motor winding of the main
armature, so that, when the load on the M D decreases, the rise of its magnetism
causes its counter tension to increase and thereby the motor current to decrease as is
required. In these two cases, the tension of the RD would therefore be opposite to
that described above, but owing to the differential winding, it would decrease as the
load on the M D decreases.
Having now particularly described the nature of my invention, and in what manner
the same is to be performed, I declare, that I claim :-
:—
1. In combination with a motor-dynamo for working in parallel, having a motor
winding and a current generator winding on the same armature: a regulating dynamo
driven from the shaft of the motor dynamo directly or by means of intermediate gear,
or from another suitable source of power, and having a field winding inserted either
in the direct primary or in the direct secondary main circuit, and an armature winding
inserted in the same or in the other of these circuits, for the purpose of regulating the
secondary tension of the motor dynamo.
2. In a motor dynamo for working in parallel, having a current generator winding
and a motor winding on the same armature: a small auxiliary armature mounted on
the same shaft and wound with a conductor which forms the continuation of one of
the said main armature windings, the small armature being placed in. a magnetic
field, the exciting coils of which are inserted in one of the main circuits, in such a
manner, that the tension produced in this armature increases the tension supplied to
the motor winding, in case the latter is continued over the armature, or that the tension
of this armature increases the tension produced by the current generator winding, in
case the latter is continued over the armature, for the purpose of regulating the
secondary tension of the motor dynamo.
r
1000
W. LAHMEYER.
By Fairfax & Wetter,
433, Strand, London, Agents.