Improvements in Transformer Switches.
Year: 1898

page_text: Date of Application, 3rd Nov., 1898-Accepted, 23rd Dec., 1898
COMPLETE SPECIFICATION.
Improvements in Transformer Switches.
I, Prof. ALFRED SCHLATTER, of Külsö Vairi út 76, Budapest V, Hungary,
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:-
In the Specification to Patent No. 17470 of 1897 is described a transformer
switch for successively putting in or out of circuit the separate members of a
group of transformers, which switch is provided with a lever arm carrying a tube
partly filled with mercury, so that when the circuit is completed there is an
automatic diminution of the moment of the lever and an increase thereof when
the circuit is broken, an accurate make and break being thus secured.
By the present invention the same purpose is achieved by substituting for the
mercury tube a contact device such as is shewn diagrammatically at c in Figs. 1^,
I and II of the accompanying drawings.
The contact fork is attached to the lever h which turns about the fulcrum d,
and is held out of action in the position shewn in Fig. I by the weight g, or
it may be a spring, and stop a. The lever is a tube and carries at its fore end a
sliding pins which is urged outward by means of an internal spring and can be
pushed inwards by external end pressure. The mercury cup of the contact
fork is included in a short circuit of the winding of the electromagnet M, such
short circuit being ordinarily open.
The contact device works as follows: -
When a transformer is put into circuit by the action of magnet M on the
switch H the weighted lever arm G moves upwards and, in pressing the pin s
back until it passes the end thereof, assumes the position shown at Fig. I^.
In this position the play of the armature, described in the said Specification to
Patent No. 17470 of 1897, is completely prevented, as the moment of the weighted
lever arm G in consequence of the counter action of the weight can be corre-
spondingly automatically diminished. The putting into circuit is therefore
accurately and securely effected.
The same is the case when a transformer is cut out of circuit since the lever
arm G cannot descend without pressing down lever h and thereby short circuiting
at e the winding of the magnet M. The magnet, therefore, remains unexcited
until the lever arm G occupies its lowest position from which it can be moved
by magnet M only when the current has its maximum strength. This short
circuiting is however only temporary, that is to say, it lasts only until the lever G
has completed its downward motion, when its end will pass the end of the pin s,
whereupon the lever h will be raised by the action of its counterweight into
its original position at Fig. I^, thereby raising the fork and breaking the
short circuit.
The same effect as this short circuiting may also be obtained by providing the
magnet M with a
reverse winding whereby the core is demagnetised by the
development of an equal and opposite degree of magnetisation, the circuit of such

page_text: winding being closed and broken by the contact v; this arrangement is shewn in
Fig. II. This figure also shews more clearly the working of the device, indicating
the mode of engagement of the two levers H and h in the three phases.
In this figure the transformer T2 is in circuit, H is above the pins s of h
and is out of contact; T3 has just been cut out of circuit, H has pressed h
down, and has made contact; T is cut out, H has passed underneath the pin s
of h so that is raised out of contact by weight g.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. In an automatic switch for successively putting in and out of circuit the
separate members of a group of transformers the use of a contact device such
as hvc which is closed by the weighted arm G of the switch lever H while the
putting out of circuit is being effected, and either short circuits the winding of
the switch magnet M or closes the circuit of an equivalent counter-winding of the
said magnet, thus demagnetising it until the switch lever has arrived at its
lowest position, which contact device has a weight 9 (or a spring) that diminishes
the moment of lever arm G when the switch is closed and that also brings the
contact device back into its position for breaking contact when lever h escapes
from its engagement with arm G, substantially as described.
2. In an automatic switch of the kind herein referred to, the combination
with the weighted lever G connected to the switch H, of a weighted lever h with
contact vc for putting electromagnet M in and out of action, such lever having
a sliding spring pin s operating in such manner that when the switch H is in
the contact position the pin s presses upwards upon lever G so as to lessen its
moment, while when lever G moves downwards it first depresses pin s and
lever h, so as to cause contactc to put the electromagnet M out of action and
then in passing the pin s, allows lever h to rise again so as to break the contact vc
substantially as and for the purpose described.
Dated this 3rd day of November 1898.
ABEL & IMRAY,
Agents for the Applicant.