silk-weaving machines
constructed by Benninger Freres; six weaving machines from the Ruti
works, near Zurich; and one knitting machine exhibited by Edward
Dubied & Co., of Couvet.
The dynamo and motor are connected to the main cable by switches of
the type shown in Fig. 5. These are specially designed to destroy the
extra current on breaking circuit by the formation of an arc which
gradually increases the resistance till the break occurs, rendering it
less sudden. One wire passes through the handle and makes contact with
the springs, and the other is attached to the clamp in which the
carbon rod is held. The current is made to enter at the carbon rod, so
that the arcs formed cause consumption of the carbon. A magnetic
cut-out--Fig. 6--is also provided to each machine; this consists of an
electro-magnet, through which the main current passes, provided with
side pole pieces. A flat soft iron plate armature is hinged so as to
come up against the pole pieces when attracted. When the current is
not sufficiently strong to cause the plate to be attracted, a hole in
the center of the latter engages over a small projection in the top of
a weighted arm hinged in the center of the board, and keeps it
upright. If now the current exceeds the limits of safety to the
machine, due to a too heavy load being thrown on, the armature is
attracted and releases the vertical arm, which falls over and enters
with considerable force between the two spring contacts below. These
contacts are connected to the field terminals, which are, therefore,
short-circuited, and prevent the dynamo generating any current. A
retractile spring can be adjusted to cause cut-off at any required
current. These details are indicated in our illustrations mounted on
their respective switch boards.
Since the erection of plant by these works at Solothurn for
transmitting 50 horse power five miles distant, which attracted so
much interest some time ago, several important works have been carried
out. Among these we may mention a 280 horse power transmission at 11/2
kilom. distance to a cotton mill at Derendingen in Switzerland, a 250
horse power transmission at 1/2 kilom. distance, carried out for Gaetano
Rossi at Piovene in Italy, and a 300 horse transmission at 6 kilom.
distance installed for Giovanni Rossi, in which the power is given off
at two different stations.--_The Engineer._
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THE ADER FLOURISH OF TRUMPETS.
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